critical thinking in fallacies

Unit 1: What Is Philosophy?

LOGOS: Critical Thinking, Arguments, and Fallacies

Heather Wilburn, Ph.D

Critical Thinking:

With respect to critical thinking, it seems that everyone uses this phrase. Yet, there is a fear that this is becoming a buzz-word (i.e. a word or phrase you use because it’s popular or enticing in some way). Ultimately, this means that we may be using the phrase without a clear sense of what we even mean by it. So, here we are going to think about what this phrase might mean and look at some examples. As a former colleague of mine, Henry Imler, explains:

By critical thinking, we refer to thinking that is recursive in nature. Any time we encounter new information or new ideas, we double back and rethink our prior conclusions on the subject to see if any other conclusions are better suited. Critical thinking can be contrasted with Authoritarian thinking. This type of thinking seeks to preserve the original conclusion. Here, thinking and conclusions are policed, as to question the system is to threaten the system. And threats to the system demand a defensive response. Critical thinking is short-circuited in authoritarian systems so that the conclusions are conserved instead of being open for revision. [1]

A condition for being recursive is to be open and not arrogant. If we come to a point where we think we have a handle on what is True, we are no longer open to consider, discuss, or accept information that might challenge our Truth. One becomes closed off and rejects everything that is different or strange–out of sync with one’s own Truth. To be open and recursive entails a sense of thinking about your beliefs in a critical and reflective way, so that you have a chance to either strengthen your belief system or revise it if needed. I have been teaching philosophy and humanities classes for nearly 20 years; critical thinking is the single most important skill you can develop. In close but second place is communication, In my view, communication skills follow as a natural result of critical thinking because you are attempting to think through and articulate stronger and rationally justified views. At the risk of sounding cliche, education isn’t about instilling content; it is about learning how to think.

In your philosophy classes your own ideas and beliefs will very likely be challenged. This does not mean that you will be asked to abandon your beliefs, but it does mean that you might be asked to defend them. Additionally, your mind will probably be twisted and turned about, which can be an uncomfortable experience. Yet, if at all possible, you should cherish these experiences and allow them to help you grow as a thinker. To be challenged and perplexed is difficult; however, it is worthwhile because it compels deeper thinking and more significant levels of understanding. In turn, thinking itself can transform us not only in thought, but in our beliefs, and our actions. Hannah Arendt, a social and political philosopher that came to the United States in exile during WWII, relates the transformative elements of philosophical thinking to Socrates. She writes:

Socrates…who is commonly said to have believed in the teachability of virtue, seems to have held that talking and thinking about piety, justice, courage, and the rest were liable to make men more pious, more just, more courageous, even though they were not given definitions or “values” to direct their further conduct. [2]

Thinking and communication are transformative insofar as these activities have the potential to alter our perspectives and, thus, change our behavior. In fact, Arendt connects the ability to think critically and reflectively to morality. As she notes above, morality does not have to give a predetermined set of rules to affect our behavior. Instead, morality can also be related to the open and sometimes perplexing conversations we have with others (and ourselves) about moral issues and moral character traits. Theodor W. Adorno, another philosopher that came to the United States in exile during WWII, argues that autonomous thinking (i.e. thinking for oneself) is crucial if we want to prevent the occurrence of another event like Auschwitz, a concentration camp where over 1 million individuals died during the Holocaust. [3] To think autonomously entails reflective and critical thinking—a type of thinking rooted in philosophical activity and a type of thinking that questions and challenges social norms and the status quo. In this sense thinking is critical of what is, allowing us to think beyond what is and to think about what ought to be, or what ought not be. This is one of the transformative elements of philosophical activity and one that is useful in promoting justice and ethical living.

With respect to the meaning of education, the German philosopher Hegel uses the term bildung, which means education or upbringing, to indicate the differences between the traditional type of education that focuses on facts and memorization, and education as transformative. Allen Wood explains how Hegel uses the term bildung: it is “a process of self-transformation and an acquisition of the power to grasp and articulate the reasons for what one believes or knows.” [4] If we think back through all of our years of schooling, particularly those subject matters that involve the teacher passing on information that is to be memorized and repeated, most of us would be hard pressed to recall anything substantial. However, if the focus of education is on how to think and the development of skills include analyzing, synthesizing, and communicating ideas and problems, most of us will use those skills whether we are in the field of philosophy, politics, business, nursing, computer programming, or education. In this sense, philosophy can help you develop a strong foundational skill set that will be marketable for your individual paths. While philosophy is not the only subject that will foster these skills, its method is one that heavily focuses on the types of activities that will help you develop such skills.

Let’s turn to discuss arguments. Arguments consist of a set of statements, which are claims that something is or is not the case, or is either true or false. The conclusion of your argument is a statement that is being argued for, or the point of view being argued for. The other statements serve as evidence or support for your conclusion; we refer to these statements as premises. It’s important to keep in mind that a statement is either true or false, so questions, commands, or exclamations are not statements. If we are thinking critically we will not accept a statement as true or false without good reason(s), so our premises are important here. Keep in mind the idea that supporting statements are called premises and the statement that is being supported is called the conclusion. Here are a couple of examples:

Example 1: Capital punishment is morally justifiable since it restores some sense of

balance to victims or victims’ families.

Let’s break it down so it’s easier to see in what we might call a typical argument form:

Premise: Capital punishment restores some sense of balance to victims or victims’ families.

Conclusion: Capital punishment is morally justifiable.

Example 2 : Because innocent people are sometimes found guilty and potentially

executed, capital punishment is not morally justifiable.

Premise: Innocent people are sometimes found guilty and potentially executed.

Conclusion: Capital punishment is not morally justifiable.

It is worth noting the use of the terms “since” and “because” in these arguments. Terms or phrases like these often serve as signifiers that we are looking at evidence, or a premise.

Check out another example:

Example 3 : All human beings are mortal. Heather is a human being. Therefore,

Heather is mortal.

Premise 1: All human beings are mortal.

Premise 2: Heather is a human being.

Conclusion: Heather is mortal.

In this example, there are a couple of things worth noting: First, there can be more than one premise. In fact, you could have a rather complex argument with several premises. If you’ve written an argumentative paper you may have encountered arguments that are rather complex. Second, just as the arguments prior had signifiers to show that we are looking at evidence, this argument has a signifier (i.e. therefore) to demonstrate the argument’s conclusion.

So many arguments!!! Are they all equally good?

No, arguments are not equally good; there are many ways to make a faulty argument. In fact, there are a lot of different types of arguments and, to some extent, the type of argument can help us figure out if the argument is a good one. For a full elaboration of arguments, take a logic class! Here’s a brief version:

Deductive Arguments: in a deductive argument the conclusion necessarily follows the premises. Take argument Example 3 above. It is absolutely necessary that Heather is a mortal, if she is a human being and if mortality is a specific condition for being human. We know that all humans die, so that’s tight evidence. This argument would be a very good argument; it is valid (i.e the conclusion necessarily follows the premises) and it is sound (i.e. all the premises are true).

Inductive Arguments : in an inductive argument the conclusion likely (at best) follows the premises. Let’s have an example:

Example 4 : 98.9% of all TCC students like pizza. You are a TCC student. Thus, you like pizza.

Premise 1: 98.9% of all TCC students like pizza

Premise 2: You are a TCC student.

Conclusion: You like pizza. (*Thus is a conclusion indicator)

In this example, the conclusion doesn’t necessarily follow; it likely follows. But you might be part of that 1.1% for whatever reason. Inductive arguments are good arguments if they are strong. So, instead of saying an inductive argument is valid, we say it is strong. You can also use the term sound to describe the truth of the premises, if they are true. Let’s suppose they are true and you absolutely love Hideaway pizza. Let’s also assume you are a TCC student. So, the argument is really strong and it is sound.

There are many types of inductive argument, including: causal arguments, arguments based on probabilities or statistics, arguments that are supported by analogies, and arguments that are based on some type of authority figure. So, when you encounter an argument based on one of these types, think about how strong the argument is. If you want to see examples of the different types, a web search (or a logic class!) will get you where you need to go.

Some arguments are faulty, not necessarily because of the truth or falsity of the premises, but because they rely on psychological and emotional ploys. These are bad arguments because people shouldn’t accept your conclusion if you are using scare tactics or distracting and manipulating reasoning. Arguments that have this issue are called fallacies. There are a lot of fallacies, so, again, if you want to know more a web search will be useful. We are going to look at several that seem to be the most relevant for our day-to-day experiences.

Inappropriate Appeal to Authority : We are definitely going to use authority figures in our lives (e.g. doctors, lawyers, mechanics, financial advisors, etc.), but we need to make sure that the authority figure is a reliable one.

Things to look for here might include: reputation in the field, not holding widely controversial views, experience, education, and the like. So, if we take an authority figure’s word and they’re not legit, we’ve committed the fallacy of appeal to authority.

Example 5 : I think I am going to take my investments to Voya. After all, Steven Adams advocates for Voya in an advertisement I recently saw.

If we look at the criteria for evaluating arguments that appeal to authority figures, it is pretty easy to see that Adams is not an expert in the finance field. Thus, this is an inappropropriate appeal to authority.

Slippery Slope Arguments : Slippery slope arguments are found everywhere it seems. The essential characteristic of a slippery slope argument is that it uses problematic premises to argue that doing ‘x’ will ultimately lead to other actions that are extreme, unlikely, and disastrous. You can think of this type of argument as a faulty chain of events or domino effect type of argument.

Example 6 : If you don’t study for your philosophy exam you will not do well on the exam. This will lead to you failing the class. The next thing you know you will have lost your scholarship, dropped out of school, and will be living on the streets without any chance of getting a job.

While you should certainly study for your philosophy exam, if you don’t it is unlikely that this will lead to your full economic demise.

One challenge to evaluating slippery slope arguments is that they are predictions, so we cannot be certain about what will or will not actually happen. But this chain of events type of argument should be assessed in terms of whether the outcome will likely follow if action ‘x” is pursued.

Faulty Analogy : We often make arguments based on analogy and these can be good arguments. But we often use faulty reasoning with analogies and this is what we want to learn how to avoid.

When evaluating an argument that is based on an analogy here are a few things to keep in mind: you want to look at the relevant similarities and the relevant differences between the things that are being compared. As a general rule, if there are more differences than similarities the argument is likely weak.

Example 7 : Alcohol is legal. Therefore, we should legalize marijuana too.

So, the first step here is to identify the two things being compared, which are alcohol and marijuana. Next, note relevant similarities and differences. These might include effects on health, community safety, economic factors, criminal justice factors, and the like.

This is probably not the best argument in support for marijuana legalization. It would seem that one could just as easily conclude that since marijuana is illegal, alcohol should be too. In fact, one might find that alcohol is an often abused and highly problematic drug for many people, so it is too risky to legalize marijuana if it is similar to alcohol.

Appeal to Emotion : Arguments should be based on reason and evidence, not emotional tactics. When we use an emotional tactic, we are essentially trying to manipulate someone into accepting our position by evoking pity or fear, when our positions should actually be backed by reasonable and justifiable evidence.

Example 8 : Officer please don’t give me a speeding ticket. My girlfriend broke up with me last night, my alarm didn’t go off this morning, and I’m late for class.

While this is a really horrible start to one’s day, being broken up with and an alarm malfunctioning is not a justifiable reason for speeding.

Example 9 : Professor, I’d like you to remember that my mother is a dean here at TCC. I’m sure that she will be very disappointed if I don’t receive an A in your class.

This is a scare tactic and is not a good way to make an argument. Scare tactics can come in the form of psychological or physical threats; both forms are to be avoided.

Appeal to Ignorance : This fallacy occurs when our argument relies on lack of evidence when evidence is actually needed to support a position.

Example 10 : No one has proven that sasquatch doesn’t exist; therefore it does exist.

Example 11 : No one has proven God exists; therefore God doesn’t exist.

The key here is that lack of evidence against something cannot be an argument for something. Lack of evidence can only show that we are ignorant of the facts.

Straw Man : A straw man argument is a specific type of argument that is intended to weaken an opponent’s position so that it is easier to refute. So, we create a weaker version of the original argument (i.e. a straw man argument), so when we present it everyone will agree with us and denounce the original position.

Example 12 : Women are crazy arguing for equal treatment. No one wants women hanging around men’s locker rooms or saunas.

This is a misrepresentation of arguments for equal treatment. Women (and others arguing for equal treatment) are not trying to obtain equal access to men’s locker rooms or saunas.

The best way to avoid this fallacy is to make sure that you are not oversimplifying or misrepresenting others’ positions. Even if we don’t agree with a position, we want to make the strongest case against it and this can only be accomplished if we can refute the actual argument, not a weakened version of it. So, let’s all bring the strongest arguments we have to the table!

Red Herring : A red herring is a distraction or a change in subject matter. Sometimes this is subtle, but if you find yourself feeling lost in the argument, take a close look and make sure there is not an attempt to distract you.

Example 13 : Can you believe that so many people are concerned with global warming? The real threat to our country is terrorism.

It could be the case that both global warming and terrorism are concerns for us. But the red herring fallacy is committed when someone tries to distract you from the argument at hand by bringing up another issue or side-stepping a question. Politicians are masters at this, by the way.

Appeal to the Person : This fallacy is also referred to as the ad hominem fallacy. We commit this fallacy when we dismiss someone’s argument or position by attacking them instead of refuting the premises or support for their argument.

Example 14 : I am not going to listen to what Professor ‘X’ has to say about the history of religion. He told one of his previous classes he wasn’t religious.

The problem here is that the student is dismissing course material based on the professor’s religious views and not evaluating the course content on its own ground.

To avoid this fallacy, make sure that you target the argument or their claims and not the person making the argument in your rebuttal.

Hasty Generalization : We make and use generalizations on a regular basis and in all types of decisions. We rely on generalizations when trying to decide which schools to apply to, which phone is the best for us, which neighborhood we want to live in, what type of job we want, and so on. Generalizations can be strong and reliable, but they can also be fallacious. There are three main ways in which a generalization can commit a fallacy: your sample size is too small, your sample size is not representative of the group you are making a generalization about, or your data could be outdated.

Example 15 : I had horrible customer service at the last Starbucks I was at. It is clear that Starbucks employees do not care about their customers. I will never visit another Starbucks again.

The problem with this generalization is that the claim made about all Starbucks is based on one experience. While it is tempting to not spend your money where people are rude to their customers, this is only one employee and presumably doesn’t reflect all employees or the company as a whole. So, to make this a stronger generalization we would want to have a larger sample size (multiple horrible experiences) to support the claim. Let’s look at a second hasty generalization:

Example 16 : I had horrible customer service at the Starbucks on 81st street. It is clear that Starbucks employees do not care about their customers. I will never visit another Starbucks again.

The problem with this generalization mirrors the previous problem in that the claim is based on only one experience. But there’s an additional issue here as well, which is that the claim is based off of an experience at one location. To make a claim about the whole company, our sample group needs to be larger than one and it needs to come from a variety of locations.

Begging the Question : An argument begs the question when the argument’s premises assume the conclusion, instead of providing support for the conclusion. One common form of begging the question is referred to as circular reasoning.

Example 17 : Of course, everyone wants to see the new Marvel movie is because it is the most popular movie right now!

The conclusion here is that everyone wants to see the new Marvel movie, but the premise simply assumes that is the case by claiming it is the most popular movie. Remember the premise should give reasons for the conclusion, not merely assume it to be true.

Equivocation : In the English language there are many words that have different meanings (e.g. bank, good, right, steal, etc.). When we use the same word but shift the meaning without explaining this move to your audience, we equivocate the word and this is a fallacy. So, if you must use the same word more than once and with more than one meaning you need to explain that you’re shifting the meaning you intend. Although, most of the time it is just easier to use a different word.

Example 18 : Yes, philosophy helps people argue better, but should we really encourage people to argue? There is enough hostility in the world.

Here, argue is used in two different senses. The meaning of the first refers to the philosophical meaning of argument (i.e. premises and a conclusion), whereas the second sense is in line with the common use of argument (i.e. yelling between two or more people, etc.).

Henry Imler, ed., Phronesis An Ethics Primer with Readings, (2018). 7-8. ↵
Arendt, Hannah, “Thinking and Moral Considerations,” Social Research, 38:3 (1971: Autumn): 431. ↵
Theodor W. Adorno, “Education After Auschwitz,” in Can One Live After Auschwitz, ed. by Rolf Tiedemann, trans. by Rodney Livingstone (Stanford: Stanford University Press, 2003): 23. ↵
Allen W. Wood, “Hegel on Education,” in Philosophers on Education: New Historical Perspectives, ed. Amelie O. Rorty (London: Routledge 1998): 302. ↵

LOGOS: Critical Thinking, Arguments, and Fallacies Copyright © 2020 by Heather Wilburn, Ph.D is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License , except where otherwise noted.

Share This Book

147 Logical Fallacies: A Master List With Examples

Logical fallacies are irrational arguments made through faulty reasoning common enough to be named for its respective logical failure.

A Complete Logical Fallacies List With Examples For Critical Thinking

contributed by Owen M. Wilson , University of Texas El Paso

A logical fallacy is an irrational argument made through faulty reasoning common enough to be named for the nature of its respective logical failure.

The A Priori Argument

Also: Rationalization; Dogmatism, Proof Texting

A corrupt argument from logos, starting with a given, pre-set belief, dogma, doctrine, scripture verse, ‘fact’ or conclusion and then searching for any reasonable or reasonable-sounding argument to rationalize, defend or justify it. Certain ideologues and religious fundamentalists are proud to use this fallacy as their primary method of ‘reasoning’ and some are even honest enough to say so.

Example: Since we know there is no such thing as ‘evolution,’ a prime duty of believers is to look for ways to explain away growing evidence, such as is found in DNA, that might suggest otherwise.

The opposite of this fallacy is the Taboo.

Have a language expert improve your writing

Check your paper for plagiarism in 10 minutes, generate your apa citations for free.

Knowledge Base
Logical Fallacies | Definition, Types, List & Examples

Logical Fallacies | Definition, Types, List & Examples

Published on April 20, 2023 by Kassiani Nikolopoulou . Revised on October 9, 2023.

A logical fallacy is an argument that may sound convincing or true but is actually flawed. Logical fallacies are leaps of logic that lead us to an unsupported conclusion. People may commit a logical fallacy unintentionally, due to poor reasoning, or intentionally, in order to manipulate others.

Because logical fallacies can be deceptive, it is important to be able to spot them in your own argumentation and that of others.

Logical fallacy list (free download), what is a logical fallacy, types of logical fallacies, what are common logical fallacies, logical fallacy examples, other interesting articles, frequently asked questions about logical fallacies.

There are many logical fallacies. You can download an overview of the most common logical fallacies by clicking the blue button.

Logical fallacy list (Google Docs)

A logical fallacy is an error in reasoning that occurs when invalid arguments or irrelevant points are introduced without any evidence to support them. People often resort to logical fallacies when their goal is to persuade others. Because fallacies appear to be correct even though they are not, people can be tricked into accepting them.

The majority of logical fallacies involve arguments—in other words, one or more statements (called the premise ) and a conclusion . The premise is offered in support of the claim being made, which is the conclusion.

There are two types of mistakes that can occur in arguments:

A factual error in the premises . Here, the mistake is not one of logic. A premise can be proven or disproven with facts. For example, If you counted 13 people in the room when there were 14, then you made a factual mistake.
The premises fail to logically support the conclusion . A logical fallacy is usually a mistake of this type. In the example above, the students never proved that English 101 was itself a useless course—they merely “begged the question” and moved on to the next part of their argument, skipping the most important part.

In other words, a logical fallacy violates the principles of critical thinking because the premises do not sufficiently support the conclusion, while a factual error involves being wrong about the facts.

There are several ways to label and classify fallacies, such as according to the psychological reasons that lead people to use them or according to similarity in their form. Broadly speaking, there are two main types of logical fallacy, depending on what kind of reasoning error the argument contains:

Informal logical fallacies

Formal logical fallacies.

An informal logical fallacy occurs when there is an error in the content of an argument (i.e., it is based on irrelevant or false premises).

Informal fallacies can be further subdivided into groups according to similarity, such as relevance (informal fallacies that raise an irrelevant point) or ambiguity (informal fallacies that use ambiguous words or phrases, the meanings of which change in the course of discussion).

“ Some philosophers argue that all acts are selfish . Even if you strive to serve others, you are still acting selfishly because your act is just to satisfy your desire to serve others.”

A formal logical fallacy occurs when there is an error in the logical structure of an argument.

Premise 2: The citizens of New York know that Spider-Man saved their city.

Conclusion: The citizens of New York know that Peter Parker saved their city.

This argument is invalid, because even though Spider-Man is in fact Peter Parker, the citizens of New York don’t necessarily know Spider-Man’s true identity and therefore don’t necessarily know that Peter Parker saved their city.

A logical fallacy may arise in any form of communication, ranging from debates to writing, but it may also crop up in our own internal reasoning. Here are some examples of common fallacies that you may encounter in the media, in essays, and in everyday discussions.

Red herring logical fallacy

The red herring fallacy is the deliberate attempt to mislead and distract an audience by bringing up an unrelated issue to falsely oppose the issue at hand. Essentially, it is an attempt to change the subject and divert attention elsewhere.

Bandwagon logical fallacy

The bandwagon logical fallacy (or ad populum fallacy ) occurs when we base the validity of our argument on how many people believe or do the same thing as we do. In other words, we claim that something must be true simply because it is popular.

This fallacy can easily go unnoticed in everyday conversations because the argument may sound reasonable at first. However, it doesn’t factor in whether or not “everyone” who claims x is in fact qualified to do so.

Straw man logical fallacy

The straw man logical fallacy is the distortion of an opponent’s argument to make it easier to refute. By exaggerating or simplifying someone’s position, one can easily attack a weak version of it and ignore their real argument.

Person 2: “So you are fine with children taking ecstasy and LSD?”

Slippery slope logical fallacy

The slippery slope logical fallacy occurs when someone asserts that a relatively small step or initial action will lead to a chain of events resulting in a drastic change or undesirable outcome. However, no evidence is offered to prove that this chain reaction will indeed happen.

Hasty generalization logical fallacy

The hasty generalization fallacy (or jumping to conclusions ) occurs when we use a small sample or exceptional cases to draw a conclusion or generalize a rule.

A false dilemma (or either/or fallacy ) is a common persuasion technique in advertising. It presents us with only two possible options without considering the broad range of possible alternatives.

In other words, the campaign suggests that animal testing and child mortality are the only two options available. One has to save either animal lives or children’s lives.

People often confuse correlation (i.e., the fact that two things happen one after the other or at the same time) with causation (the fact that one thing causes the other to happen).

It’s possible, for example, that people with MS have lower vitamin D levels because of their decreased mobility and sun exposure, rather than the other way around.

It’s important to carefully account for other factors that may be involved in any observed relationship. The fact that two events or variables are associated in some way does not necessarily imply that there is a cause-and-effect relationship between them and cannot tell us the direction of any cause-and-effect relationship that does exist.

If you want to know more about fallacies , research bias , or AI tools , make sure to check out some of our other articles with explanations and examples.

ChatGPT vs human editor
ChatGPT citations
Is ChatGPT trustworthy?
Using ChatGPT for your studies
Sunk cost fallacy
Straw man fallacy
Slippery slope fallacy
Either or fallacy
Appeal to emotion fallacy
Non sequitur fallacy

Research bias

Implicit bias
Framing bias
Cognitive bias
Optimism bias
Hawthorne effect
Affect heuristic

An ad hominem (Latin for “to the person”) is a type of informal logical fallacy . Instead of arguing against a person’s position, an ad hominem argument attacks the person’s character or actions in an effort to discredit them.

This rhetorical strategy is fallacious because a person’s character, motive, education, or other personal trait is logically irrelevant to whether their argument is true or false.

Name-calling is common in ad hominem fallacy (e.g., “environmental activists are ineffective because they’re all lazy tree-huggers”).

An appeal to ignorance (ignorance here meaning lack of evidence) is a type of informal logical fallacy .

It asserts that something must be true because it hasn’t been proven false—or that something must be false because it has not yet been proven true.

For example, “unicorns exist because there is no evidence that they don’t.” The appeal to ignorance is also called the burden of proof fallacy .

People sometimes confuse cognitive bias and logical fallacies because they both relate to flawed thinking. However, they are not the same:

Cognitive bias is the tendency to make decisions or take action in an illogical way because of our values, memory, socialization, and other personal attributes. In other words, it refers to a fixed pattern of thinking rooted in the way our brain works.
Logical fallacies relate to how we make claims and construct our arguments in the moment. They are statements that sound convincing at first but can be disproven through logical reasoning.

In other words, cognitive bias refers to an ongoing predisposition, while logical fallacy refers to mistakes of reasoning that occur in the moment.

Sources in this article

We strongly encourage students to use sources in their work. You can cite our article (APA Style) or take a deep dive into the articles below.

Nikolopoulou, K. (2023, October 09). Logical Fallacies | Definition, Types, List & Examples. Scribbr. Retrieved September 10, 2024, from https://www.scribbr.com/fallacies/logical-fallacy/

Jin, Z., Lalwani, A., Vaidhya, T., Shen, X., Ding, Y., Lyu, Z., Sachan, M., Mihalcea, R., & Schölkopf, B. (2022). Logical Fallacy Detection. arXiv (Cornell University) . https://doi.org/10.48550/arxiv.2202.13758

Is this article helpful?

Kassiani Nikolopoulou

Other students also liked, slippery slope fallacy | definition & examples, what is a red herring fallacy | definition & examples, what is straw man fallacy | definition & examples, get unlimited documents corrected.

✔ Free APA citation check included ✔ Unlimited document corrections ✔ Specialized in correcting academic texts

Table of Contents
Random Entry
Chronological
Editorial Information
About the SEP
Editorial Board
How to Cite the SEP
Special Characters
Advanced Tools
Support the SEP
PDFs for SEP Friends
Make a Donation
SEPIA for Libraries
Entry Contents

Bibliography

Academic tools.

Friends PDF Preview
Author and Citation Info
Back to Top

Two competing conceptions of fallacies are that they are false but popular beliefs and that they are deceptively bad arguments. These we may distinguish as the belief and argument conceptions of fallacies. Academic writers who have given the most attention to the subject of fallacies insist on, or at least prefer, the argument conception of fallacies, but the belief conception is prevalent in popular and non-scholarly discourse. As we shall see, there are yet other conceptions of what fallacies are, but the present inquiry focuses on the argument conception of fallacies.

Being able to detect and avoid fallacies has been viewed as a supplement to criteria of good reasoning. The knowledge of fallacies is needed to arm us against the most enticing missteps we might take with arguments—so thought not only Aristotle but also the early nineteenth century logicians Richard Whately and John Stuart Mill. But as the course of logical theory from the late nineteenth-century forward turned more and more to axiomatic systems and formal languages, the study of reasoning and natural language argumentation received much less attention, and hence developments in the study of fallacies almost came to a standstill. Until well past the middle of the twentieth century, discussions of fallacies were for the most part relegated to introductory level textbooks. It was only when philosophers realized the ill fit between formal logic, on the one hand, and natural language reasoning and argumentation, on the other, that the interest in fallacies has returned. Since the 1970s the utility of knowing about fallacies has been acknowledged (Johnson and Blair 1993), and the way in which fallacies are incorporated into theories of argumentation has been taken as a sign of a theory’s level of adequacy (Biro and Siegel 2007, van Eemeren 2010).

In modern fallacy studies it is common to distinguish formal and informal fallacies. Formal fallacies are those readily seen to be instances of identifiable invalid logical forms such as undistributed middle and denying the antecedent. Although many of the informal fallacies are also invalid arguments, it is generally thought to be more profitable, from the points of view of both recognition and understanding, to bring their weaknesses to light through analyses that do not involve appeal to formal languages. For this reason it has become the practice to eschew the symbolic language of formal logic in the analysis of these fallacies; hence the term ‘informal fallacy’ has gained wide currency. In the following essay, which is in four parts, it is what is considered the informal-fallacy literature that will be reviewed. Part 1 is an introduction to the core fallacies as brought to us by the tradition of the textbooks. Part 2 reviews the history of the development of the conceptions of fallacies as it is found from Aristotle to Copi. Part 3 surveys some of the most recent innovative research on fallacies, and Part 4 considers some of the current research topics in fallacy theory.

1. The core fallacies

2.1 aristotle, 2.3 arnauld and nicole, 2.6 bentham, 2.7 whately, 2.9 sidgwick, 3.1 renewed interest, 3.2 doubts about fallacies, 3.3 the informal logic approach to fallacies, 3.4 the formal approach to informal fallacies, 3.5 the epistemic approach to fallacies, 3.6 dialectical/dialogical approaches to fallacies, 4.1 the nature of fallacies, 4.2 the appearance condition, 4.3 teaching, other internet resources, related entries.

Irving Copi’s 1961 Introduction to Logic gives a brief explanation of eighteen informal fallacies. Although there is some variation in competing textbooks, Copi’s selection captured what for many was the traditional central, core fallacies. [ 1 ] In the main, these fallacies spring from two fountainheads: Aristotle’s Sophistical Refutations and John Locke’s An Essay Concerning Human Understanding (1690). By way of introduction, a brief review of the core fallacies, especially as they appear in introductory level textbooks, will be given. Only very general definitions and illustrations of the fallacies can be offered. This proviso is necessary first, because, the definitions (or identity conditions) of each of the fallacies is often a matter of contention and so no complete or final definition can be given in an introductory survey; secondly, some researchers wish that only plausible and realistic instances of each fallacy be used for illustration. This also is not possible at this stage. The advantage of the stock examples of fallacies is that they are designed to highlight what the mistake associated with each kind of fallacy is supposed to be. Additional details about some of the fallacies are found in Sections 2 and 3. As an initial working definition of the subject matter, we may take a fallacy to be an argument that seems to be better than it really is.

1. The fallacy of equivocation is an argument which exploits the ambiguity of a term or phrase which has occurred at least twice in an argument, such that on the first occurrence it has one meaning and on the second another meaning. A familiar example is:

The end of life is death. Happiness is the end of life. So, death is happiness.

‘The end of life’ first means ceasing to live, then it means purpose. That the same set of words is used twice conceals the fact that the two distinct meanings undermine the continuity of the reasoning, resulting in a non-sequitur .

2. The fallacy of amphiboly is, like the fallacy of equivocation, a fallacy of ambiguity; but here the ambiguity is due to indeterminate syntactic structure. In the argument:

The police were told to stop drinking on campus after midnight. So, now they are able to respond to emergencies much better than before

there are several interpretations that can be given to the premise because it is grammatically ambiguous. On one reading it can be taken to mean that it is the police who have been drinking and are now to stop it; this makes for a plausible argument. On another reading what is meant is that the police were told to stop others (e.g., students) from drinking after midnight. If that is the sense in which the premise is intended, then the argument can be said to be a fallacy because despite initial appearances, it affords no support for the conclusion.

3 & 4. The fallacies of composition and division occur when the properties of parts and composites are mistakenly thought to be transferable from one to the other. Consider the two sentences:

Every member of the investigative team was an excellent researcher.
It was an excellent investigative team.

Here it is ‘excellence’ that is the property in question. The fallacy of composition is the inference from (a) to (b) but it need not hold if members of the team cannot work cooperatively with each other. The reverse inference from (b) to (a)—the fallacy of division—may also fail if some essential members of the team have a supportive or administrative role rather than a research role.

5. The fallacy of begging the question ( petitio principii ) can occur in a number of ways. One of them is nicely illustrated with Whately’s (1875 III §13) example: “to allow everyman an unbounded freedom of speech must always be, on the whole, advantageous to the State; for it is highly conducive to the interest of the Community, that each individual should enjoy a liberty perfectly unlimited, of expressing his sentiments.” This argument begs the question because the premise and conclusion are the very same proposition, albeit expressed in different words. It is a disguised instance of repetition which gives no reason for its apparent conclusion.

Another version of begging the question can occur in contexts of argumentation where there are unsettled questions about key terms. Suppose, for example, that everyone agrees that to murder someone requires doing something that is wrong, but not everyone agrees that capital punishment is a form of ‘murder’; some think it is justified killing. Then, should an arguer gives this argument:

Capital punishment requires an act of murdering human beings. So, capital punishment is wrong.

one could say that this is question-begging because in this context of argumentation, the arguer is smuggling in as settled a question that remains open. That is, if the premise is accepted without further justification, the arguer is assuming the answer to a controversial question without argument.

Neither of these versions of begging the question are faulted for their invalidity, so they are not charged with being non-sequitors like most of the core fallacies; they are, however, attempted proofs that do not transparently display their weakness. This consideration, plus its ancient lineage back to Aristotle, might explain begging the question’s persistent inclusion among fallacies. But, given our allegiance to the modern conception of logic as being solely concerned with the following-from relation, forms of begging the question should be thought of as epistemic rather than logical fallacies.

Some versions of begging the question are more involved and are called circular reasoning. They include more than one inference. Descartes illustrated this kind of fallacy with the example of our belief in the Bible being justified because it is the word of God, and our belief in God’s existence being justified because it is written in the Bible. [ 2 ] The two propositions lead back and forth to each other, in a circle, each having only the support of the other.

6. The fallacy known as complex question or many questions is usually explained as a fallacy associated with questioning. For example, in a context where a Yes or No answer must be given, the question, “Are you still a member of the Ku Klux Klan?” is a fallacy because either response implies that one has in the past been a member of the Klan, a proposition that may not have been established as true. Some say that this kind of mistake is not really a fallacy because to ask a question is not to make an argument.

7. There are a number of fallacies associated with causation, the most frequently discussed is post hoc ergo propter hoc , (after this, therefore because of this). This fallacy ascribes a causal relationship between two states or events on the basis of temporal succession. For example,

Unemployment decreased in the fourth quarter because the government eliminated the gasoline tax in the second quarter.

The decrease in unemployment that took place after the elimination of the tax may have been due to other causes; perhaps new industrial machinery or increased international demand for products. Other fallacies involve confusing the cause and the effect, and overlooking the possibility that two events are not directly related to each other but are both the effect of a third factor, a common cause. These fallacies are perhaps better understood as faults of explanation than faults of arguments.

8. The fallacy of ignoratio elenchi , or irrelevant conclusion, is indicative of misdirection in argumentation rather than a weak inference. The claim that Calgary is the fastest growing city in Canada, for example, is not defeated by a sound argument showing that it is not the biggest city in Canada. A variation of ignoratio elenchi , known under the name of the straw man fallacy, occurs when an opponent’s point of view is distorted in order to make it easier to refute. For example, in opposition to a proponent’s view that (a) industrialization is the cause of global warming, an opponent might substitute the proposition that (b) all ills that beset mankind are due to industrialization and then, having easily shown that (b) is false, leave the impression that (a), too, is false. Two things went wrong: the proponent does not hold (b), and even if she did, the falsity of (b) does not imply the falsity of (a).

There are a number of common fallacies that begin with the Latin prefix ‘ ad ’ (‘to’ or ‘toward’) and the most common of these will be described next.

9. The ad verecundiam fallacy concerns appeals to authority or expertise. Fundamentally, the fallacy involves accepting as evidence for a proposition the pronouncement of someone who is taken to be an authority but is either not really an authority or a relevant authority. This can happen when non-experts parade as experts in fields in which they have no special competence—when, for example, celebrities endorse commercial products or social movements. Similarly, when there is controversy, and authorities are divided, it is an error to base one’s view on the authority of just some of them. (See also 2.4 below.)

10. The fallacy ad populum is similar to the ad verecundiam , the difference being that the source appealed to is popular opinion, or common knowledge, rather than a specified authority. So, for example:

These days everyone (except you) has a car and knows how to drive; So, you too should have a car and know how to drive.

Often in arguments like this the premises aren’t true, but even if they are generally true they may provide only scant support for their conclusions because that something is widely practised or believed is not compelling evidence that it is true or that it should be done. There are few subjects on which the general public can be said to hold authoritative opinions. Another version of the ad populum fallacy is known as “playing to the gallery” in which a speaker seeks acceptance for his view by arousing relevant prejudices and emotions in his audience in lieu of presenting it with good evidence.

11. The ad baculum fallacy is one of the most controversial because it is hard to see that it is a fallacy or even that it involves bad reasoning. Ad baculum means “appeal to the stick” and is generally taken to involve a threat of injury of harm to the person addressed. So, for example,

If you don’t join our demonstration against the expansion of the park, we will evict you from your apartment; So, you should join our demonstration against the expansion of the park.

Such threats do give us reasons to act but, unpleasant as the interlocutor may be, there seems to be no fallacy here. In labour disputes, and perhaps in international relations, using threats such as going on strike, or cutting off trade routes, are not normally considered fallacies, even though they do involve intimidation and the threat of harm. However, if we change to doxastic considerations, then the argument that you should believe that candidate $X$ is the one best suited for public office because if you do not believe this you will be evicted from your apartment, certainly is a good instance of irrelevant evidence.

12. The fallacy ad misericordiam is a companion to the ad baculum fallacy: it occurs not when threats are out of place but when appeals for sympathy or pity are mistakenly thought to be evidence. To what extent our sympathy for others should influence our actions depends on many factors, including circumstances and our ethical views. However, sympathy alone is generally not evidence for believing any proposition. Hence,

You should believe that he is not guilty of embezzling those paintings; think of how much his family suffered during the Depression.

Ad misericordiam arguments, like ad baculum arguments, have their natural home in practical reasoning; it is when they are used in theoretical (doxastic) argumentation that the possibility of fallacy is more likely.

13. The ad hominem fallacy involves bringing negative aspects of an arguer, or their situation, to bear on the view they are advancing. There are three commonly recognized versions of the fallacy. The abusive ad hominem fallacy involves saying that someone’s view should not be accepted because they have some unfavorable property.

Thompson’s proposal for the wetlands may safely be rejected because last year she was arrested for hunting without a license.

The hunter Thompson, although she broke the law, may nevertheless have a very good plan for the wetlands.

Another, more subtle version of the fallacy is the circumstantial ad hominem in which, given the circumstances in which the arguer finds him or herself, it is alleged that their position is supported by self-interest rather than by good evidence. Hence, the scientific studies produced by industrialists to show that the levels of pollution at their factories are within the law may be undeservedly rejected because they are thought to be self-serving. Yet it is possible that the studies are sound: just because what someone says is in their self-interest, does not mean it should be rejected.

The third version of the ad hominem fallacy is the tu quoque . It involves not accepting a view or a recommendation because the espouser him- or herself does not follow it. Thus, if our neighbor advises us to exercise regularly and we reject her advice on the basis that she does not exercise regularly, we commit the tu quoque fallacy: the value of advice is not wholly dependent on the integrity of the advisor.

We may finish our survey of the core fallacies by considering just two more.

14. The fallacy of faulty analogy occurs when analogies are used as arguments or explanations and the similarities between the two things compared are too remote to support the conclusion.

If a child gets a new toy he or she will want to play with it; So, if a nation gets new weapons, it will want to use them.

In this example (due to Churchill 1986, 349) there is a great difference between using (playing with) toys and using (discharging) weapons. The former is done for amusement, the latter is done to inflict harm on others. Playing with toys is a benign activity that requires little justification; using weapons against others nations is something that is usually only done after extensive deliberation and as a last resort. Hence, there is too much of a difference between using toys and using weapons to conclude that a nation, if it acquires weapons, will want to use them as readily as children will want to play with their toys.

15. The fallacy of the slippery slope generally takes the form that from a given starting point one can by a series of incremental inferences arrive at an undesirable conclusion, and because of this unwanted result, the initial starting point should be rejected. The kinds of inferences involved in the step-by-step argument can be causal, as in:

You have decided not to go to college; If you don’t go to college, you won’t get a degree; If you don’t get a degree, you won’t get a good job; If you don’t get a good job, you won’t be able to enjoy life; But you should be able to enjoy life; So, you should go to college.

The weakness in this argument, the reason why it is a fallacy, lies in the second and third causal claims. The series of small steps that lead from an acceptable starting point to an unacceptable conclusion may also depend on vague terms rather than causal relations. Lack of clear boundaries is what enables the puzzling slippery slope arguments known as “the beard” and “the heap.” In the former, a person with a full beard eventually becomes beardless as hairs of the beard are removed one-by-one; but because the term ‘beard’ is vague it is unclear at which intermediate point we are to say that the man is now beardless. Hence, at each step in the argument until the final hair-plucking, we should continue to conclude that the man is bearded. In the second case, because ‘heap’ is vague, it is unclear at what point piling scattered stones together makes them a heap of stones: if it is not a heap to begin with, adding one more stone will not make it a heap, etc. In both these cases apparently good reasoning leads to a false conclusion.

Many other fallacies have been named and discussed (see, e.g., Nickerson 2021, ch. 6), some of them quite different from the ones mentioned above, others interesting and novel variations of the above. Some of these will be mentioned in the review of historical and contemporary sources that follows.

2. History of Fallacy Theory

The history of the study of fallacies begins with Aristotle’s work, On Sophistical Refutations . It is among his earlier writings and the work appears to be a continuation of the Topics , his treatise on dialectical argumentation. Although his most extensive and theoretically detailed discussion of fallacies is in the Sophistical Refutations , Aristotle also discusses fallacies in the Prior Analytics and On Rhetoric . Here we will concentrate on summarizing the account given in the Sophistical Refutations . In that work, four things are worth noting: (a) the different conceptions of fallacy; (b) the basic concepts used to explain fallacies; (c) Aristotle’s explanation of why fallacies can be deceptive; and (d) his enumeration and classification of fallacies.

2.1.1 Definitions

At the beginning of Topics (I, i), Aristotle distinguishes several kinds of deductions (syllogisms). They are distinguished first on the basis of the status of their premises. (1) Those that begin from true and primary premises, or are owed to such, are demonstrations. (2) Those which have dialectical premises—propositions acceptable to most people, or to the wise—are dialectical deductions. (3) Deductions that start from premises which only appear to be dialectical, are fallacious deductions because of their starting points, as are (4) those “deductions” that do have dialectical premises but do not really necessitate their conclusions. Other fallacies mentioned and associated with demonstrations are (5) those which only appear to start from what is true and primary ( Top ., I, i 101a5). What this classification leaves out are (6) the arguments that do start from true and primary premises but then fail to necessitate their conclusions; two of these, begging the question and non-cause are discussed in Prior Analytics (II, 16, 17). It is the “fallacious deductions” characterized in (4), however, that come closest to the focus of the Sophistical Refutations . Nevertheless, in many of the examples given what stands out is that the premises are given as answers in dialogue and are to be maintained by the answerer, not necessarily that they are dialectical in the sense of being common opinions. This variation on dialectical deductions Aristotle calls examination arguments ( SR 2 165b4).

2.1.2 The basic concepts

There are three closely related concepts needed to understand sophistical refutations. By a deduction (a syllogism [ 3 ] ) Aristotle meant an argument which satisfies three conditions: it “is based on certain statements made in such a way as necessarily to cause the assertion of things other than those statements and as a result of those statements” ( SR 1 165a1–2). Thus an argument may fail to be a syllogism in three different ways. The premises may fail to necessitate the conclusion, the conclusion may be the same as one of the premises, and the conclusion may not be caused by (grounded in) the premises. The concept of a proof underlying Sophistical Refutations is similar to what is demanded of demonstrative knowledge in Posterior Analytics (I ii 71b20), viz., that the premises must be “true, primary, immediate, better known than, prior to, and causative of the conclusion,” except that the first three conditions do not apply to deductions in which the premises are obtained through questioning. A refutation , Aristotle says, is “a proof of the contradictory” ( SR 6, 168a37)—a proof of the proposition which is the contradictory of the thesis maintained by the answerer. In a context of someone, S , maintaining a thesis, T , a dialectical refutation will consist in asking questions of S , and then taking S ’s answers and using them as the premises of a proof via a deduction of not-T : this will be a refutation of T relative to the answerer ( SR 8 170a13). The concept of contradiction can be found in Categories : it is those contraries which are related such that “one opposite needs must be true, while the other must always be false” (13b2–3). A refutation will be sophistical if either the proof is only an apparent proof or the contradiction is only an apparent contradiction. Either way, according to Aristotle, there is a fallacy. Hence, the opening of his treatise: “Let us now treat of sophistical refutations, that is, arguments which appear to be refutations but are really fallacies and not refutations” ( SR 1 164a20).

2.1.3 The appearance condition

Aristotle observed that “reasoning and refutation are sometimes real and sometimes not, but appear to be real owing to men’s inexperience; for the inexperienced are like those who view things from a distance” ( SR , 1 164b25). The ideas here are first that there are arguments that appear to be better than they really are; and second that people inexperienced in arguments may mistake the appearance for the reality and thus be taken in by a bad argument or refutation. Apparent refutations are primarily explained in terms of apparent deductions: thus, with one exception, Aristotle’s fallacies are in the main a catalogue of bad deductions that appear to be good deductions. The exception is ignoratio elenchi in which, in one of its guises, the deduction contains no fallacy but the conclusion proved only appears to contradict the answerer’s thesis.

Aristotle devotes considerable space to explaining how the appearance condition may arise. At the outset he mentions the argument that turns upon names ( SR 1 165a6), saying that it is the most prolific and usual explanation: because there are more things than names, some names will have to denote more than one thing, thereby creating the possibility of ambiguous terms and expressions. That the ambiguous use of a term goes unnoticed allows the illusion that an argument is a real deduction. The explanation of how the false appearance can arise is in the similarity of words or expressions with different meanings, and the smallness of differences in meaning between some expressions ( SR 7 169a23–169b17).

2.1.4 List and classification

Aristotle discusses thirteen ways in which refutations can be sophistical and divides them into two groups. The first group, introduced in Chapter 4 of On Sophistical Refutations , includes those Aristotle considers dependent on language ( in dictione ), and the second group, introduced in Chapter 5, includes those characterized as not being dependent on language ( extra dictionem ). Chapter 6 reviews all the fallacies from the view point of failed refutations, and Chapter 7 explains how the appearance of correctness is made possible for each fallacy. Chapters 19–30 advise answerers on how to avoid being taken in by sophistical refutations.

The fallacies dependent on language are equivocation, amphiboly, combination of words, division of words, accent and form of expression. Of these the first two have survived pretty much as Aristotle thought of them. Equivocation results from the exploitation of a term’s ambiguity and amphiboly comes about through indefinite grammatical structure. The one has to do with semantical ambiguity, the other with syntactical ambiguity. However, the way that Aristotle thought of the combination and division fallacies differs significantly from modern treatments of composition and division. Aristotle’s fallacies are the combinations and divisions of words which alter meanings, e.g., “walk while sitting” vs. “walk-while-sitting,” (i.e., to have the ability to walk while seated vs. being able to walk and sit at the same time). For division, Aristotle gives the example of the number 5: it is 2 and 3. But 2 is even and 3 is odd, so 5 is even and odd. Double meaning is also possible with those words whose meanings depend on how they are pronounced, this is the fallacy of accent, but there were no accents in written Greek in Aristotle’s day; accordingly, this fallacy would be more likely in written work. What Aristotle had in mind is something similar to the double meanings that can be given to ‘unionized’ and ‘invalid’ depending on how they are pronounced. Finally, the fallacy that Aristotle calls form of expression exploits the kind of ambiguity made possible by what we have come to call category mistakes, in this case, fitting words to the wrong categories. Aristotle’s example is the word ‘flourishing’ which may appear to be a verb because of its ‘ing’ ending (as in ‘cutting’ or ‘running’) and so belongs to the category of actions, whereas it really belongs in the category of quality. Category confusion was, for Aristotle, the key cause of metaphysical mistakes.

There are seven kinds of sophistical refutation that can occur in the category of refutations not dependent on language: accident, secundum quid , consequent, non-cause, begging the question, ignoratio elenchi and many questions.

The fallacy of accident is the most elusive of the fallacies on Aristotle’s list. It turns on his distinction between two kinds of predication, unique properties and accidents ( Top . I 5). The fallacy is defined as occurring when “it is claimed that some attribute belongs similarly to the thing and to its accident” ( SR 5 166b28). What belongs to a thing are its unique properties which are counterpredicable (Smith 1997, 60), i.e., if $A$ is an attribute of $B$, $B$ is an attribute of $A$. However, attributes that are accidents are not counterpredicates and to treat them as such is false reasoning, and can lead to paradoxical results; for example, if it is a property of triangles that they are equal to two right angles, and a triangle is accidentally a first principle, it does not follow that all first principles have two right angles (see Schreiber 2001, ch. 7).

Aristotle considers the fallacy of consequent to be a special case of the fallacy of accident, observing that consequence is not convertible, i.e., “if $A$ is, $B$ necessarily is, men also fancy that, if $B$ is, $A$ necessarily is” ( SR 5 169b3). One of Aristotle’s examples is that it does not follow that “a man who is hot must be in a fever because a man who is in a fever is hot” ( SR 5 169b19). This fallacy is sometimes claimed as being an early statement of the formal fallacy of affirming the consequent.

The fallacy of secundum quid comes about from failing to appreciate the distinction between using words absolutely and using them with qualification. Spruce trees, for example, are green with respect to their foliage (they are ‘green’ with qualification); it would be a mistake to infer that they are green absolutely because they have brown trunks and branches. It is because the difference between using words absolutely and with qualification can be minute that this fallacy is possible, thinks Aristotle.

Begging the question is explained as asking for the answer (the proposition) which one is supposed to prove, in order to avoid having to make a proof of it. Some subtlety is needed to bring about this fallacy such as a clever use of synonymy or an intermixing of particular and universal propositions ( Top . VIII, 13). If the fallacy succeeds the result is that there will be no deduction: begging the question and non-cause are directly prohibited by the second and third conditions respectively of being a deduction ( SR 6 168b23).

The fallacy of non-cause occurs in contexts of ad impossibile arguments when one of the assumed premises is superfluous for deducing the conclusion. The superfluous premise will then not be a factor in deducing the conclusion and it will be a mistake to infer that it is false since it is a non-cause of the impossibility. This is not the same fallacy mentioned by Aristotle in the Rhetoric (II 24) which is more akin to a fallacy of empirical causation and is better called false cause (see Woods and Hansen 2001).

Aristotle’s fallacy of many questions occurs when two questions are asked as if they are one proposition. A proposition is “a single predication about a single subject” ( SR 6 169a8). Thus with a single answer to two questions one has two premises for a refutation , and one of them may turn out to be idle, thus invalidating the deduction (it becomes a non-cause fallacy). Also possible is that extra-linguistic part-whole mistakes may happen when, for example, given that something is partly good and partly not-good, the double question is asked whether it is all good or all not-good? Either answer will lead to a contradiction (see Schreiber 2000, 156–59). Despite its name, this fallacy consists in the ensuing deduction, not in the question which merely triggers the fallacy.

On one interpretation ignoratio elenchi is considered to be Aristotle’s thirteenth fallacy, in which an otherwise successful deduction fails to end with the required contradictory of the answerer’s thesis. Seen this way, ignoratio elenchi is unlike all the other fallacies in that it is not an argument that fails to meet one of the criteria of a good deduction, but a genuine deduction that turns out to be irrelevant to the point at issue. On another reading, ignoratio elenchi is not a separate fallacy but an alternative to the language dependent / language independent way of classifying the other twelve fallacies: they all fail to meet, in one way or another, the requirements of a sound refutation.

[A] refutation is a contradiction of one and the same predicate, not of a name but of a thing, and not of a synonymous name but of an identical name, based on the given premises and following necessarily from them (the original point at issue not being included) in the same respect, manner and time. ( SR 5 167a23–27)

Each of the other twelve fallacies is analysed as failing to meet one of the conditions in this definition of refutation ( SR 6). Aristotle seems to favour this second reading, but it leaves the problem of explaining how refutations that miss their mark can seem like successful refutations. A possible explanation is that a failure to contradict a given thesis can be made explicit by adding the negation of the thesis as a last step of the deduction, thereby insuring the contradiction of the thesis, but only at the cost (by the last step) of introducing one of the other twelve fallacies in the deduction.

2.1.5 Different interpretations

I have given only the briefest possible explanation of Aristotle’s fallacies. To really understand them a much longer engagement with the original text and the secondary sources is necessary. The second chapter of Hamblin’s (1970) book is a useful introduction to the Sophistical Refutations , and a defence of the dialectical nature of the fallacies. Hamblin thinks that a dialectical framework is indispensable for an understanding of Aristotle’s fallacies and that part of the poverty of contemporary accounts of fallacies is due to a failure to understand their assumed dialectical setting. This approach to the fallacies is continued in contemporary research by some argumentation theorists, most notably Douglas Walton (1995) who also follows Aristotle in recognizing a number of different kinds of dialogues in which argumentation can occur; Frans van Eemeren and Rob Grootendorst (2004) who combine dialectical and pragmatic insights with an ideal model of a critical discussion; and Jaakko Hintikka who analyses the Aristotelian fallacies as mistakes in question-dialogues (Hintikka 1987; Bachman 1995.) According to Hintikka (1997) it is an outright mistake to think of Aristotle’s fallacies primarily as mistaken inferences, either deductive or inductive. A non-dialogue oriented interpretation of Aristotle fallacies is found in Woods and Hansen (1997 and 2001) who argue that the fallacies (apparent deductions) are basic to apparent refutations, and that Aristotle’s interest in the fallacies extended beyond dialectical contests, as is shown by his interest in them in the Prior Analytics and the Rhetoric (II 24). What gives unity to Aristotle’s different fallacies on this view is not a dialogue structure but rather their dependence on the concepts of deduction and proof. The most thorough recent study of these questions is in Schreiber (2003), who emphasizes Aristotle’s concern with resolving (exposing) fallacies and argues that it is Aristotelian epistemology and metaphysics that is needed for a full understanding of the fallacies in the Sophistical Refutations .

Francis Bacon deserves a brief mention in the history of fallacy theory, not because he made any direct contribution to our knowledge of the fallacies but because of his attention to prejudice and bias in scientific investigation, and the effect they could have on our beliefs. He spoke of false idols (1620, aphorisms 40–44) as having the same relation to the interpretation of nature that fallacies have to logic. The idol of the tribe is human nature which distorts our view of the natural world (it is a false mirror). The idol of the cave is the peculiarity of each individual man, our different abilities and education that affect how we interpret nature. The idols of the theatre are the acquired false philosophies, systems and methods, both new and ancient, that rule men’s minds. These three idols all fall into the category of explanations of why we may misperceive the world. A fourth of Bacon’s idols, the idol of the market place, is the one that comes closest to the Aristotelian tradition as it points to language as the source of our mistaken ideas: “words plainly force and overrule the understanding, and throw all into confusion, and lead men away into numberless empty controversies and idle fancies” (1620, aphorism 43). Although Bacon identifies no particular fallacies in Aristotle’s sense, he opens the door to the possibility that there may be false assumptions associated with the investigation of the natural world. The view of The New Organon is that just as logic is the cure for fallacies, so will the true method of induction be a cure for the false idols.

Antoine Arnauld and Pierre Nicole were the authors of Logic, or the Art of Thinking (1662), commonly known as the Port-Royal Logic. According to Benson Mates (1965, 214) it “is an outstanding early example of the ‘how to think straight’ genre.” The work includes chapters on sophisms, with the justification that “examples of mistakes to be avoided are often more striking than the examples to be imitated” (Bk. III, xix). The Port-Royal Logic does not continue Aristotle’s distinction between fallacies that are dependent on language and those that are not; instead there is a division between sophisms associated with scientific subjects (ibid.)—these are nearly all from the Sophistical Refutations —and those committed in everyday life and ordinary discourse (Bk III, xx). The division is not exclusive, with some of the sophisms fitting both classes.

The Port-Royal Logic includes eight of Aristotle’s original thirteen fallacies, several of them modified to fit the bent to natural philosophy rather than dialectical argumentation. Several kinds of causal errors are considered under the broad heading, non causa pro causa and they are illustrated with reference to scientific explanations that have assigned false causes for empirical phenomena. Also identified as a common fallacy of the human mind is post hoc, ergo propter hoc : “This happened following a certain thing, hence that thing must be its cause” (Bk. III, xix 3). Begging the questions is included and illustrated, interestingly, with examples drawn from Aristotelian science. Two new sophisms are included: one is imperfect enumeration, the error of overlooking an alternative, the other is a faulty (incomplete) induction, what we might call hasty generalization. Although the discussions here are brief, they mark the entry of inductive fallacies into the pool of present day recognized fallacies. Ignoratio elenchi retains its dialogical setting but is extended beyond the mere failure to contradict a thesis, “to attribut[ing] to our adversaries something remote from their views to gain an advantage over them, or to impute to them consequences we imagine can be drawn from their doctrines, although they disavow and deny them” (Bk. III, xix 1). The other Aristotelian fallacies included are accident, combination and division, secundum quid and ambiguity.

The sophisms of everyday life and ordinary discourse are eight in number and two of them, the sophisms of authority and manner, should be noticed. In these sophisms, external marks of speakers contribute to the persuasiveness of their arguments. Although authority is not to be doubted in church doctrines, in matters that God has left to the discernment of humans we can be led away from the truth by being too deferential. Here we find one of the earliest statements of the modern appeal to false authority: people are often persuaded by certain qualities that are irrelevant to the truth of the issue being discussed. Thus there are a number of people who unquestioningly believe those who are the oldest and most experienced, even in matters that depend neither on age nor experience, but only on mental insight (Bk. III, xx 6). To age and experience Arnauld and Nicole add noble birth as an unwarranted source of deference in matters intellectual (Bk. III, xx 7), and towards the end of their discussion they add the sophism of manner, cautioning that “grace, fluency, seriousness, moderation and gentleness” is not necessarily a mark of truth (Bk. III, xx 8). The authors seem to have the rhetorical flourishes of royal courtiers especially in mind.

It is John Locke who is credited with intentionally creating a class of ad -arguments, and inadvertently giving birth to the class of ad -fallacies. In An Essay Concerning Human Understanding (1690), he identified three kinds of arguments, the ad verecundiam , ad ignorantiam , and ad hominem arguments, each of which he contrasted with ad judicium arguments which are arguments based on “the foundations of knowledge and probability” and are reliable routes to truth and knowledge. Locke did not speak of ad -arguments as fallacies—that was left to others to do later—but rather as kinds of arguments “that men, in their reasoning with others, do ordinarily make use of to prevail on their assent; or at least so to awe them as to silence their opposition.” (Bk IV, xvii, 19–22).

Two of the ad arguments have developed beyond how Locke originally conceived them. His characterization of the ad verecundiam is considered the locus classicus of appeal-to-authority arguments. When it is a fallacy it is either on the ground that authorities (experts) are fallible or for the reason that appealing to authority is an abandonment of an individual’s epistemic responsibility. It seems unlikely, however, that Locke thought we should never rely on the expertise and superior knowledge of others when engaged in knowledge-gathering and argumentation. This leads us to consider what kind of authority Locke might have had in mind. In addition to epistemic and legal (command) authority there is also what might be called social authority, demanding respect and deference from others due to one’s higher social standing, something much more a part of seventeenth-century society than it is a part of ours. The language that Locke used in connection with the ad verecundiam , words like ‘eminency’, ‘dignity’, ‘breach of modesty’, and ‘having too much pride’ suggests that what he had in mind was the kind of authority that demands respect for the social standing of sources rather than for their expertise; hence, by this kind of authority a person could be led to accept a conclusion because of their modesty or shame, more so than for the value of the argument (see Goodwin 1998). Hence, we understand Locke better when we translate ad verecundiam literally, as “appeal to modesty.”

The argumentum ad hominem , as Locke defined it, has subsequently developed into three different fallacies. His original description was that it was a way “to press a man with consequences drawn from his own principles or concessions.” That is, to argue that an opponent’s view is inconsistent, logically or pragmatically, with other things he has said or to which he is committed. Locke’s observation was that such arguments do not advance us towards truth, but that they can serve to promote agreement or stall disagreement. To argue that way is not a fallacy but an acceptable mode of argumentation. Henry Johnstone (1952) thought it captured the essential character of philosophical argumentation. The modern descendants of the Lockean ad hominem are the abusive ad hominem which is an argument to the effect that a position should not be accepted because of some telling negative property of its espouser; the circumstantial ad hominem , an argument to the effect that someone’s position should be rejected because circumstances suggest that their view is the result of self-interested bias; and finally, the tu quoque ad hominem argument which attempts to deflect a criticism by pointing out that it applies equally to the accuser. Recent scholarship suggests that these post-Lockean kinds of ad hominem arguments are sometimes used fairly, and sometimes fallaciously; but none of them is what Locke described as the argumentum ad hominem .

Ad ignorantiam translates as “appeal to ignorance.” Locke’s characterization of this kind of argument is that it demands “the adversary to admit what they allege as a proof, or to assign a better.” The ignorance in question is comparative, it is not that the opponent has no evidence, it is that s/he has no better evidence. However, the inability of an opponent to produce a better argument is not sufficient reason to think the proponent’s argument must be accepted. Modern versions of this kind of argument take it as a fallacy to infer a proposition to be true because there is no evidence against it (see Krabbe, 1995).

The introduction and discussion of the ad -arguments appears almost as an afterthought in Locke’s Essay . It is found at the end of the chapter, “Of Reason,” in which Locke devotes considerable effort to criticizing syllogistic logic. Reasoning by syllogisms, he maintained, was neither necessary nor useful for knowledge. Locke clearly thought that the three ad -arguments were inferior to ad judicium arguments, but he never used the term ‘fallacy’ in connection with them, although he did use it in connection with errors of syllogistic reasoning.

Was Locke the first to discuss these kinds of arguments? Hamblin (1970, 161–62) and Nuchelmans (1993) trace the idea of ad hominem arguments back to Aristotle, and Locke’s remark that the name argumentum ad hominem was already known has been investigated by Finocchiaro (1974) who finds the term and the argument kind in Galileo’s writings more than a half-century before the Essay Concerning Human Understanding . And Arnauld and Nicole’s discussion of the sophism of authority, that “people speak the truth because they are of noble birth or wealthy or in high office,” which seems to be part of Locke’s ad verecundiam , was most likely known to him. Subsequently more ad -arguments were added to the four that Locke identified (see Watts, and Copi, below).

Isaac Watts in his Logick; or, The Right Use of Reason (1724), furthered the ad -argument tradition by adding three more arguments: argumentum ad fidem (appeal to faith), argumentum ad passiones (appeal to passion), and argumentum ad populum (a public appeal to passions). Like Locke, Watts does not consider these arguments as fallacies but as kinds of arguments. However, the Logick does consider sophisms and introduces “false cause” as an alternative name for non causa pro causa which here, as in the Port-Royal Logic, is understood as a fallacy associated with empirical causation. According to Watts it occurs whenever anyone assigns “the reasons of natural appearances, without sufficient experiments to prove them” (1796, Pt. III, 3 i 4). Another sophism included by Watts is imperfect enumeration or false induction, the mistake of generalizing on insufficient evidence. Also, the term ‘strawman fallacy’ may have its origins in Watts’s discussion of ignoratio elenchi : after having dressed up the opinions and sentiments of their adversaries as they please to make “images of straw”, disputers “triumph over their adversary as though they had utterly confuted his opinions” (1796, Pt. III 3 i 1).

Jeremy Bentham’s Handbook of Political Fallacies (1824) was written in the years leading up to the first Reform Bill (1832). His interest was in political argumentation, particularly in exposing the different means used by parliamentarians and law makers to defeat or delay reform legislation. Hence, it was not philosophy or science that interested him, but political debate. Fallacies he took to be arguments or topics that would through the use of deception produce erroneous beliefs in people (1824, 3). These tactics he (or his editor) divided into four classes: fallacies of authority, danger, delay and confusion. Bentham was aware of the developing ad -fallacies tradition since each of the thirty or so fallacies he described is also labelled as belonging either to the kind ad verecundiam (appeal to shame or modesty), ad odium (appeal to hate or contempt), ad metum (appeal to fear or threats), ad quietem (appeal to rest or inaction), ad judicium , and ad socordiam (appeal to postponement or delay). Most of Bentham’s fallacies have not become staples of fallacy theory but many of them show interesting insights into the motives and techniques of debaters (see e.g., Rudanko’s (2021) analyses of the ad socordiam ).

Bentham’s Handbook has not taken a central place in the history of fallacy studies (Hamblin 1970, 165–69); nevertheless, it is historically interesting in several respects. It discusses authority at length, identifying four conditions for reliable appeals to authority and maintaining that the failure of any one of them cancels the strength of the appeal. Fallacies of authority in political debate occur when authority “is employed in the place of such relevant arguments as might have been brought forward” (1824, 25). Bentham’s fear is that debaters will resort to “the authority” of traditional beliefs and principles instead of considering the advantages of the reform measures under discussion.

Under the heading “fallacies of danger” Bentham named a number of what he called vituperative fallacies—imputations of bad character, bad motive, inconsistency, and suspicious connections—which have as their common characteristic, “the endeavour to draw aside attention from the measure to the man , in such a way as to cause the latter’s badness to be imputed to the measure he supports, or his goodness to his opposition” (1824, 83). This characterization fits well with the way we have come to think of the ad hominem fallacy as a view disparaged by putting forth a negative characterization of its supporter or his circumstances.

Bentham places the fallacies in the immediate context of debate, identifying ways in which arguers frustrate the eventual resolution of disagreements by using insinuations of danger, delaying tactics, appeals to questionable authorities and, generally, confusing issues. Modern argumentation theorists who hold that any impediment to the successful completion of dialogical discussions is a fallacy, may find that their most immediate precursor was Bentham (see Grootendorst 1997).

Book III of Richard Whately’s Elements of Logic (1826) is devoted to giving an account of fallacies based on “logical principles,”. Whately was instrumental in the revival of interest in logic at the beginning of the nineteenth century and, being committed to deductivism, he maintained that only valid deductive inferences counted as reasoning. Thus, he took every fallacy to belong to either the class of deductive failures (logical fallacies) or the class of non-logical failures (material fallacies).

By ‘fallacy’ Whately meant “any unsound mode of arguing, which appears to demand our conviction, and to be decisive of the question at hand, when in fairness it is not”’ (Bk. III, intro.). The logical fallacies divide into the purely logical and the semi-logical fallacies. The purely logical fallacies are plain violations of syllogistic rules like undistributed middle and illicit process. The semi-logical fallacies mostly trade on ambiguous middle terms and are therefore also logical fallacies, but their detection requires extra-logical knowledge including that of the senses of terms [ 4 ] and knowledge of the subject matter (Bk. III, §2); they include, among others, the fallacies of ambiguity, and division and composition. The non-logical, material fallacies are also divided into two classes: fallacies with premises ‘unduly assumed,’ and fallacies of irrelevant conclusions. Begging the question fits under the heading of a non-logical, material fallacy in which a premise has been unduly assumed, and ignoratio elenchi is a non-logical, material fallacy in which an irrelevant conclusion has been reached. The ad -arguments are all placed under the last division as variants of ignoratio elenchi , but they are said to be fallacies only when they are used unfairly. Whately’s version of the ad hominem argument resembles Locke’s in that it is an ex concessis kind of argument: one that depends on the concessions of the person with whom one is arguing. From the concessions, one might prove that one’s opponent is ‘committed to p, ’ but an attempt to make it seem as if this constitutes a proof of the absolute (non-relative) proposition ‘ p ’ would be a fallacy. This kind of ad hominem fallacy can be seen as falling under the broader ignoratio elenchi category because what is proved is not what is needed.

The creation of the category of non-logical fallacies was not really a break with Aristotle as much as it was a break with what had become the Aristotelian tradition. Aristotle thought that some fallacies were due to unacceptable premises although these are not elaborated in Sophistical Refutations (see section 2.1.1 above). Whately’s creation of the category of non-logical fallacies solved the problem of what to do with begging the question which is not an invalid form of argument, and it also created a place in fallacy taxonomy for the ad -fallacies.

John Stuart Mill’s contribution to the study of fallacies is found in Book V of his comprehensive A System of Logic, Ratiocinative and Inductive , first published in 1843. It stands out most strikingly for placing the study of fallacies within his framework of inductive reasoning, a direct rejection of Whately’s deductivist approach to reasoning and fallacies. Mill held that only inductive reasoning counts as inferring and accordingly he introduces new categories as well as a new classification scheme for fallacies.

Mill drew a division between the moral and the intellectual causes of fallacies. The former are aspects of human nature such as biases and indifference to truth which incline us to make intellectual mistakes. These dispositions are not themselves fallacies. It is the intellectual errors, the actual taking of insufficient evidence as sufficient, that are fallacious. The various ways in which this can happen are what Mill took as the basis for classifying fallacies. “A catalogue of the varieties of evidence which are not real evidence,” he wrote, “is an enumeration of fallacies” (1891, Bk.V iii §1).

Mill divided the broad category of argument fallacies into two groups: those in which the evidence is distinctly conceived and those in which it is indistinctly conceived. Fallacies falling under evidence indistinctly conceived (Bk. V, vii) were further described as fallacies of confusion. These result from an indistinct conception of the evidence leading to a mistaking of its significance and thereby to an unsupported conclusion. Some of the traditional Aristotelian fallacies such as ambiguity, composition and division, petitio principii , and ignoratio elenchi , are placed in this category. Although Mill followed Whately closely in his exposition of the fallacies of confusion, he does not mention any ad -arguments in connection with ignoratio elenchi .

As for the category of fallacies of evidence distinctly conceived, it too is divided. The two sub-classes are fallacies of ratiocination (deduction) and fallacies of induction. The deductive fallacies (Bk.V, vi) are those that explicitly break a rule of the syllogism, such as the three-term rule. But also included are the conversion of universal affirmatives and particular negatives (“All PS” does not follow from “All SP,” and “Some P not S” does not follow from “Some S not P”). Also included in this category is the secundum quid fallacy.

The other sub-class of fallacies distinctly conceived bring out what is distinctive about Mill’s work on the fallacies: that it is the first extensive attempt to deal with fallacies of induction. He divided inductive fallacies into two further groups: fallacies of observation (V, iv) and fallacies of generalization (Bk. V, v). Fallacies of observation can occur either negatively or positively. Their negative occurrence consists in non-observation in which one has overlooked negatively relevant evidence. This is similar to what the Port-Royal Logic considered a faulty enumeration, and one of Mill’s examples is the continued faith that farmers put in the weather forecasts found in almanacs despite their long history of false predictions. Observation fallacies occur positively when the mistake is based on something that is seen wrongly, i.e., taken to be something that it is not. Such mal-observations occur when we mistake our inferences for facts, as in our inference that the sun rises and sets (Bk. V, iv, 5).

Fallacies of generalization, the other branch of inductive fallacies, result from mistakes in the inductive process which can happen in several ways. As one example, Mill pointed to making generalizations about what lies beyond our experience: we cannot infer that the laws that operate in remote parts of the universe are the same as those in our solar system (Bk. V, v, 2). Another example is mistaking empirical laws stating regularities for causal laws—his example was because women as a class have not hitherto equalled men as a class, they will never be able to do so (Bk. V, v, 4). Also placed in the category of fallacies of generalization is post hoc ergo propter hoc , which tends to single out a single cause when there are in reality many contributing causes (Bk. V, v, 5). Analogical arguments are identified as a false basis for generalizations; they are “at best only admissible as an inconclusive presumption, where real proof is unattainable” (Bk. V, v, 6).

Mill also included what he calls fallacies of inspection, or a priori fallacies (Bk. V, iii) in his survey of fallacies. These consist of non-inferentially held beliefs, so they fit the belief conception of fallacies rather than the argument conception. Among Mill’s examples of a priori fallacies are metaphysical assumptions such as that distinctions of language correspond to distinctions in nature, and that objects cannot affect each other at a distance. Even the belief in souls or ghosts is considered an a priori fallacy. Such beliefs will not withstand scrutiny, thought Mill, by the inductive method strictly applied.

A System of Logic is the most extensive work on fallacies since Aristotle’s Sophistical Refutations . Mill’s examples are taken from a wide range of examples in science, politics, economics, religion and philosophy. His classificatory scheme is original and comprehensive. Frederick Rosen (2006) argues that Mill’s pre-occupation with the detection and prevention of fallacies is part of what motivates the celebrated second chapter of On Liberty . Despite these considerations, the Logic is not much referenced by fallacy theorists.

In a series of articles and books beginning in 1878 and continuing well into the twentieth century, Alfred Sidgwick wrote repeatedly about fallacies. Unlike Whately and Mill who thought that searching for fallacies was a supplement to their logical methods (deduction and induction, respectively), Sidgwick wanted to put argument evaluation by fallacies at the centre of logic. In his view, the negative method of evaluating arguments by searching them for fallacies is a more practical and efficient way of judging arguments in actual life than the positive method of trying to match arguments with the positive standards of formal logic. His earliest proposal (1878) was to pass arguments through a sieve, or filter, which would eliminate arguments if they had the marks of any of the fallacies. Sidgwick placed the category of fallacies of confusion (those due to ambiguity or vagueness), including ignoratio elenchi , at the top of the sieve. At the next level down is petitio principii and arguments from occult causes, and below that fallacies of ratiocination (deductive, syllogistic fallacies) and inductive reasoning. An argument that succeeds in passing all the way through the sieve should be considered logically good. He thought most fallacies would be revealed at the top level as fallacies of confusion.

Sidgwick’s contribution is not to the definition of fallacies, nor to the identification of new fallacies, but rather to his promotion of the idea, worked out in some detail in Fallacies: A view of logic from the practical side (1884), that a systematic search for fallacy mistakes could be a comprehensive and practical method of evaluating arguments found in daily life. He was one of the first to argue that the new mathematical interpretations of logic being advanced in the second-half of the nineteenth century could not do justice to natural language arguments, and he was also an advocate for reform in how logic should be taught so as to make it practically valuable to students. Although Sidgwick’s work is little known today, it is fair to say that he anticipated many of the concerns that would occupy informal logic a hundred years later.

Irving Copi’s Introduction to Logic —an influential text book from the mid-twentieth century—defines a fallacy as “a form of argument that seems to be correct but which proves, upon examination, not to be so.” (1961, 52) The term ‘correct’ is sufficiently broad to allow for both deductive invalidity, inductive weakness, as well as some other kinds of argument failure. Of the eighteen informal fallacies Copi discusses, eleven can be traced back to the Aristotelian tradition, and the other seven to the burgeoning post-Lockean ad -fallacy tradition.

The first division in Copi’s classification is between formal and informal fallacies. Formal fallacies are invalid inferences which “bear a superficial resemblance” to valid forms of inference, so these we may think of as deductive fallacies. They include affirming the consequent, denying the antecedent, the fallacy of four terms, undistributed middle, and illicit major. Informal fallacies are not characterized as resembling formally valid arguments; they gain their allure some other way. One division of informal fallacies is the fallacies of relevance which are “errors in reasoning into which we may fall because of carelessness and inattention to our subject matter” (1961, 53). This large class of fallacies includes accident, converse accident, false cause, petitio principii , complex question, ignoratio elenchi , ad baculum , ad hominem abusive, ad hominem circumstantial, ad ignorantiam , ad misericordiam , ad populum , and ad verecundiam . The other division of informal fallacies is called fallacies of ambiguity and it includes equivocation, amphiboly, accent, composition and division.

It seems that Copi took Whately’s category of semi-logical fallacies and moved them under a new heading of ‘informal fallacies,’ presumably for the reason that extra-logical knowledge is needed to uncover their invalidity. This has the result that the new wide category of informal fallacies is a mixed bag: some of them are at bottom logical failures (equivocation, composition, ad misericordiam ) and some are logically correct but frustrate proof (begging the question, ignoratio elenchi ). [ 5 ] Copi’s classification, unlike Whately’s which sought to make a distinction on logical grounds, may be seen as based on three ways that fallacies resemble good arguments: formal fallacies have invalid forms that resemble valid forms, fallacies of ambiguity resemble good arguments through the ambiguity of terms, and fallacies of relevance exploit psychological (non-logical) associations. Hence, we may think of Copi’s divisions as between logical, semantic and psychological fallacies.

Copi’s treatment of the fallacies is a fair overview of the traditional list of fallacies, albeit he did not pretend to do any more than give an introduction to existing fallacy-lore for beginning logic students. Hamblin (1970, ch. 1) criticized Copi’s work, along with that of several others, and gave it the pejorative name, “the standard treatment of fallacies.” His criticisms rang true with many of his readers, thereby provoking contempt for the traditional treatment of fallacies as well as stimulating research in what we may call the new, or post-Hamblin, era, of fallacy studies. Let us next consider some of these developments.

3. New approaches to fallacies

A common complaint since Whately’s Elements of Logic is that our theory and teaching of fallacies are in want of improvement—he thought they should be put on a more logical footing to overcome the loose and vague treatments others had proffered.

It is on Logical principles therefore that I propose to discuss the subject of Fallacies. … the generality of Logical writers have usually followed so opposite a plan. Whenever they have to treat of anything that is beyond the mere elements of Logic, they totally lay aside all reference to the principles they have been occupied in establishing and explaining, and have recourse to a loose, vague, and popular kind of language … [which is] … strangely incongruous in a professional Logical treatise. (1875, III, intro.)

Charles Hamblin’s 1970 book, Fallacies , revives Whately’s complaint. We may view Fallacies as the dividing line between traditional approaches to the study of fallacies and new, contemporary approaches. At the time of its publication it was the first book-length work devoted to fallacies in modern times. The work opens with a critique of the standard treatment of fallacies as it was found in mid-twentieth century textbooks; then, in subsequent chapters, it takes a historical turn reviewing Aristotle’s approach to fallacies and exploring the tradition it fostered (as in the previous section of this entry). Other historically-oriented chapters include one on the Indian tradition, and one on formal fallacies. Hamblin’s more positive contributions to fallacy studies are concentrated in the book’s later chapters on the concept of argument, formal dialectics, and equivocation.

What Hamblin meant by “the standard treatment of fallacies” was:

The typical or average account as it appears in the typical short chapter or appendix of the average modern textbook. And what we find in most cases, I think it should be admitted, is as debased, worn-out and dogmatic a treatment as could be imagined—incredibly tradition bound, yet lacking in logic and in historical sense alike, and almost without connection to anything else in modern Logic at all. (1970, 12)

Let us consider what came before Hamblin as the traditional approach to fallacies and what comes after him as new approaches. The new approaches (since the 1970’s) show a concern to overcome Hamblin’s criticisms, and they also vie with each to produce the most defensible alternative to the traditional approach. One thing that nearly all the new approaches have in common is that they reject what Hamblin presents as the nearly universally accepted definition of “fallacy” as an argument “that seems to be valid but is not so” (1970, 12). Although this definition of fallacy is not nearly as widely accepted as Hamblin intimated (see Hansen 2002), others have taken to calling it “the standard definition of fallacies” and for convenience we can refer to it as SDF. SDF has three necessary conditions: a fallacy (i) is an argument, (ii) that is invalid, and (iii) appears to be valid. These can be thought of as the argument condition, the invalidity condition and the appearance condition. All three conditions have been brought into question.

Maurice Finocchiaro continued Hamblin’s criticism of the modern textbook treatment of fallacies, observing that they contain very few examples of actual fallacies, leading him to doubt the validity of ‘fallacy’ as a genuine logical category. Although he allows that errors in reasoning are common in real life, he thinks that “types of logically incorrect arguments”—fallacies—are probably not common (1981, 113). For that reason Finocchiaro prefers to speak of fallacious arguments —by which he means arguments in which the conclusion fails to follow from the premises—rather than fallacies (1987, 133). He further distances himself from SDF by not considering the appearance condition.

Finocchiaro distinguishes six ways in which arguments can be fallacious. (1) Formal fallaciousness is simply the case where the conclusion does not follow validly from the premises; this type of error can be demonstrated by producing a suitable analogous counter-example in which the premises are true and the conclusion is false. (2) Explanatory fallaciousness occurs when a specified conclusion follows with no more certainty from the given premises than does a rival conclusion; it occurs most often in the context of proposing explanatory hypotheses. (3) Presuppositional fallaciousness occurs in those cases where an argument depends on a false presupposition; this kind of fallaciousness is demonstrated by making a sound argument showing the presupposition to be false. (4) Positive fallaciousness occurs when the given premises, complemented by other propositions taken as true, are shown to support a conclusion inconsistent with the given conclusion. (5) Semantical fallaciousness results from the ambiguity of terms; the conclusion will follow if the sense given to the term in the premises makes the premises false, but if the other sense is ascribed to the term, making the premises true, the conclusion does not follow (it becomes an instance of formal fallaciousness). (6) Finally, Finocchiaro singles out persuasive fallaciousness , in which the conclusion does not follow from the premises because it is the same as one of the premises. As a test of completeness of this six-fold division of fallaciousness, Finocchiaro (1987) observes that it is adequate to classify all the kinds of errors which Galileo found in the arguments of the defenders of the geocentric view of the solar system.

Gerald Massey (1981) has voiced a strong objection to fallacy theory and the teaching of fallacies. He argues that there is no theory of invalidity—no systematic way to show that an argument is invalid other than to show that it has true premises and a false conclusion (1981, 164). Hence, there is an asymmetry between proving arguments valid and proving them invalid: they are valid if they can be shown to be an instance of a valid form, but they are not proved invalid by showing that they are an instance of an invalid form, because both valid and invalid arguments instantiate invalid forms. Thus, showing that a natural language argument is an instance of an invalid form does not preclude the possibility that it is also an instance of a valid form, and therefore valid. Since upholders of SDF maintain that fallacies are invalid arguments, Massey’s asymmetry thesis has the consequence that no argument can be convicted of being a fallacy on logical grounds. [ 6 ]

The informal logic approach to fallacies is taken in Johnson and Blair’s Logical Self-Defense , a textbook first published in 1977. It was prompted in part by Hamblin’s indictment of the standard treatment and it further develops an initiative taken by Kahane (1971) to develop university courses that were geared to everyday reasoning. Johnson and Blair’s emphasis is on arming students to defend themselves against fallacies in everyday discourse, and a fundamental innovation is in their conception of a good argument. In place of a sound argument—a deductively valid argument with true premises—Johnson and Blair posit an alternative ideal of a cogent argument , one whose premises are acceptable, relevant to and sufficient for its conclusion. Acceptability replaces truth as a premise requirement, and the validity condition is split in to two different conditions, premise relevance and premise sufficiency. Acceptability is defined relative to audiences—the ones for whom arguments are intended—but the other basic concepts, relevance and sufficiency, although illustrated by examples, remain as intuitive, undefined concepts (see Tindale, 2007). Premise sufficiency (strength) is akin to probability in that it is a matter of degree but Johnson and Blair do not pursue giving it numerical expression.

The three criteria of a cogent argument, individually necessary and jointly sufficient, lead to a conception of fallacy as “any argument that violates one of the criteria of good argument … and is committed frequently in argumentative discourse” (1993, 317–18). This shares only one condition with SDF: that a fallacy is an argument. (Deductive) validity is replaced with the broader concept sufficiency, and the appearance condition is not included. Johnson (1987) argued that the appearance condition makes the occurrence of fallacies too subjective since how things appear may vary from perceiver to perceiver, and it should therefore be replaced by a frequency requirement. To be a fallacy, a mistake must occur with sufficient frequency to be worth our attention.

The adoption of the concept of a cogent argument as an ideal has several consequences. The category of fallacies with problematic premises (reminiscent of Whately’s “premises unduly assumed”) shows a concern with argument evaluation over and beyond logical or inference evaluation, drawing the informal logic approach away from purely logical concerns towards an epistemic conception of fallacies. Having both sufficiency and relevance as criteria (instead of the single validity criterion) has the benefit of allowing the making of nuanced judgments about the level of premise support: for example, we might say that an argument’s premises, although insufficient, are nevertheless positively relevant to the conclusion. Irrelevant premise fallacies are those with no premise support at all, whereas insufficient premise fallacies are those in which there is some support, but not enough of it. The informal logicians’ conception of fallacies is meant to be broader and more suitable to natural language argumentation than would be a conception tied only to deductive invalidity.

Johnson and Blair concern themselves exclusively with informal fallacies. Many of the familiar Aristotelian fallacies that are part of the standard treatment are missing from their inventory (e.g., accident, composition and division) and the ones retained find themselves in new categories: begging the question and ambiguity are together under the heading of Problematic Premise; appeals to authority and popularity are placed under the heading of Hasty Conclusion fallacies; ad hominem is among the fallacies that belong in the third category, Fallacies of Irrelevant Reason. This new list of fallacies has a different bent than many earlier lists, being more geared to deal with arguments in popular, everyday communication than philosophical or scientific discourse; this is evident both by the omission of some of the traditional fallacies as well as by the introduction of new ones, such as dubious assumption, two wrongs, slippery slope, and faulty analogy.

The kinds of mistakes one can make in reasoning are generally thought to be beyond enumeration and, hence, it has been maintained that there can be no complete stock of fallacies that will guard against every kind of mistake. Johnson and Blair’s approach is responsive to this problem in that it allows the names of the classes of fallacies — ‘unacceptable premise,’ ‘irrelevant reason’ and ‘hasty conclusion’ — to stand for fallacies themselves, fallacies broad-in-scope; i.e., to serve “both as general principles of organization, and as back-ups to fill in any gaps between specific labels belonging within each genus” (1993, 52). Hence, any violation of one of the criteria of a cogent argument can be considered a fallacy.

In addition to this alternative theoretical approach to fallacies built on the three criteria of a cogent argument—an approach also taken up by others [ 7 ] —informal logic’s contribution to fallacy studies lies in its attempts to provide better analyses of fallacies, a programme pursued by a large number of researchers, including Govier (1982) on the slippery slope, Wreen (1989) on the ad baculum , Walton (1991) on begging the question, Brinton (1995) on the ad hominem , Freeman (1995) on the appeal to popularity, Pinto (1995) on post hoc ergo propter hoc and Finocchiaro (2023) on the fallacy of composition.

John Woods also despairs of the standard treatment but he sees in it something of importance; namely that the fallacies most often reviewed in introductory level logic textbooks “are a kind of caricature of their associated improprieties, which lie deeply imbedded in human practice” (Woods 1992, 25). The fallacies are then behavioural symptoms of kinds of irrationality to which humans are highly susceptible, and that makes them an important subject for study because they say something about human nature. Therefore, the problem with the standard treatment, according to Woods, is not that it is a misdirected research programme, but rather that it has been poorly carried out, partly because logicians have failed to appreciate that a multi-logical approach is necessary to understand the variety of fallacies. This idea, pursued jointly by Woods and Douglas Walton (1989), is that, for many of the fallacies standard formal logic is inadequate to uncover the unique kind of logical mistakes in question—it is too coarse conceptually to reveal the unique character of many of the fallacies. To get a satisfactory analysis of each of the fallacies they must be matched with a fitting logical system, one that has the facility to uncover the particular logical weakness in question. Inductive logic can be employed for analysis of hasty generalization and post hoc ergo propter hoc ; relatedness logic is appropriate for ignoratio elenchi ; plausible reasoning theory for the ad verecundiam , and dialectical game theory for begging the question and many questions. Woods (1992, 43) refers to this approach to studying the fallacies as methodological pluralism. Thus, like the informal logicians, there is here an interest in getting the analyses of each of the fallacies right, but the Woods and Walton approach involves embracing formal methods, not putting them aside.

Woods (2013) has continued his research on fallacies, most recently considering them in the context of what he calls a naturalized logic (modelled on Quine’s naturalized epistemology). The main point of this naturalizing move is that a theory of reasoning should take into account the abilities and motivations of reasoners. Past work on the fallacies has identified them as failing to satisfy the rules of either deductive or inductive logic, but Woods now wants to consider the core fallacies in light of what he calls third-way reasoning (comparable to non-monotonic reasoning), an account of the cognitive practices that closely resemble our common inferential practices. From the perspective of third-way reasoning the “rules” implicit in the fallacies present themselves as heuristic directives to reasoners rather than as fallacies; hence, it may be that learning from feedback (having errors corrected) is less trouble than learning the rules to avoid fallacies in the first place (Woods 2013, p. 215). Woods illustrates his point by recalling many of the fallacies he originally identified in his 1992 paper, and subjecting them to this revised model of analysis thereby overturning the view that these types of argument are always to be spurned.

SDF may be seen as closely tied to the logical approach to fallacies—the fault in arguments it singles out is their deductive invalidity. But this conception of fallacies turns out to be inadequate to cover the variety of the core fallacies in two ways: it is too narrow because it excludes begging the question which is not invalid, and it is too wide because it condemns good but non-deductive arguments as fallacies (given that they also satisfy the appearance condition) because they are invalid. Even if we replace the invalidity condition in SDF with some less stringent standard of logical weakness which could overcome the “too wide” problem, it would still leave the difficulty of accounting for the fallacy of begging the question unsolved.

Siegel and Biro (1992, 1995) hold an epistemic account of fallacies, contrasting their view with dialectical/rhetorical approaches, because matters extraneous to arguments, such as being a practice that leads to false beliefs or not being persuasive, are not in their view a sufficient condition to make an argument a fallacy. They take the position that “it is a conceptual truth about arguments that their central … purpose is to provide a bridge from known truths or justified beliefs to as yet unknown … truths or as yet unjustified beliefs” (1992, 92). Only arguments that are “epistemically serious” can accomplish this; that is, only arguments that satisfy the extra-formal requirement that premises are knowable independently of their conclusions, and are more acceptable epistemically than their conclusions, can fulfill this function. A purely logical approach to argument will not capture this requirement because arguments of the same valid form, but with different contents, may or may not be epistemically serious, depending on whether the premises are epistemically acceptable relative to the conclusion.

Modifying Biro’s (1977, 265–66) examples we can demonstrate how the requirement of epistemic seriousness plays out with begging the question. Consider these two arguments:

All men are mortal; Obama is a man; So, Obama is mortal.

All members of the committee are old Etonians; Fortesque is a member of the committee; Fortesque is an old Etonian.

In the first argument the premises are knowable independently of the conclusion. The major premise can be deduced from other universal premises about animals, and the minor premise, unlike the conclusion which must be inferred, can be known by observation. Hence, this argument does not beg the question. However, in the second argument (due to Biro, 1977) given the minor premise, the major cannot be known to be true unless the conclusion is known to be true. Consequently, on the epistemic approach to fallacies taken by Biro and Siegel, the second argument, despite the fact that it is valid, is non-serious, it begs the question, and it is a fallacy. If there was some independent way of knowing whether the major premise was true, such as that it was a bylaw that only old Etonians could be committee members, the argument would be a serious one, and not beg the question.

Biro and Siegel’s epistemic account of fallacies is distinguishable in at least three ways. First, it insists that the function of arguments is epistemic, and therefore anything that counts as a fallacy must be an epistemic fault, a breaking of a rule of epistemic justification. But since logical faults are also epistemic faults, the epistemic approach to fallacies will include logical fallacies, although these must also be explicable in terms of epistemic seriousness. Second, since the epistemological approach does not insist that all justification must be deductive, it allows the possibility of their being fallacies (as well as good arguments) by non-deductive standards, something precluded by SDF. Finally, we notice that the appearance condition is not considered a factor in this discussion of fallacies.

Ulrike Hahn and Mike Oaksford (2006a, 2006b) see themselves as contributing to the epistemic approach to fallacy analysis by developing a probabilistic analysis of the fallacies. It is part of their programme for a normative theory of natural language argumentation. They are motivated by what they perceive as the shortcomings in other approaches. The logical (deductive) approach falls short in that it simply divides arguments into valid and invalid arguments thereby failing to appreciate that natural language arguments come in various degrees of strength. The alternative approaches to fallacies, given by procedural (dialectical) and consensual accounts, they criticize on the basis that they fail to address the central problem raised by the fallacies: that of the strength of the reason-claim complex. In Hahn and Oaksford’s view the strength or weakness of the classical fallacies (they are concerned mostly with the post-Aristotelian ones) is not a result of their structure or their context of use. It is instead a matter of the relationship between the evidence and the claim (the contents of the premises and the conclusion). Evaluation of this relationship is thought to be best captured by a probabilistic Bayesian account; accordingly, they adapt Bayes’ theorem to arguments evaluation with the proviso that the probabilities are subjective degrees of belief, not frequencies. “An argument’s strength,” they write, “is a function of an individual’s initial level of belief in the claim, the availability and observation of confirmatory (or disconfirmatory) evidence, and the existence and perceived strength of competing hypotheses” (Corner, et al. 1145). With Korb (2003) they view a fallacy as an argument with a low probability on the Bayesian model.

Since the variance in input probabilities will result in a range of outputs in argument strength, this probabilistic approach has the potential to assign argument strengths anywhere between 0 and 1, thereby allowing that different tokens of one argument type can vary greatly in strength, i.e., some will be fallacies and others not. Also, and this seems to concur with our experience, different arguers may disagree on the strength of the same arguments since they can differ in the assignments of the initial probabilities. Hahn and Oaksford also claim as advantages for their normative theory that it gives guidance for persuasion since it takes into account the initial beliefs of audiences. Moreover, their approach contributes to the study of belief change; that is, to what extent our confidence in the conclusion changes with the availability of new evidence.

Some of the most active new researchers on fallacies take a dialectical and/or dialogical approach. This can be traced back to Hamblin (1970, ch. 8) and Lorenzen’s (1969) dialogue theory. The panacea for fallacies that Whately recommended was more logic; Hamblin, however, proposed a shift from the logical to the dialectical perspective.

[W]e need to extend the bounds of Formal Logic; to include features of dialectical contexts within which arguments are put forward. To begin with, there are criteria of validity of argument that are additional to formal ones: for example, those that serve to proscribe question-begging. To go on with, there are prevalent but false conceptions of the rules of dialogue, which are capable of making certain argumentative moves seem satisfactory and unobjectionable when, in fact, they conceal and facilitate dialectical malpractice. (Hamblin 1970, 254)

The proposal here is to shift the study of fallacies from the contexts of arguments to the contexts of dialogues (argumentation), formulate rules for reasonable dialogue activity, and then connect fallacies to failures of rule-following. Barth and Martens’s paper (1977), which studied the argumentum ad hominem by extending Lorenzen’s dialogue tableaux method to include the definitions of the concepts “line of attack” and “winning strategy,” leads to a conception of fallacies as either failures to meet one of the necessary conditions of rational dialogical argumentation, or failures to satisfy sufficient conditions as specified by production rules of the dialogical method (1977, 96).

The Barth and Martens paper is a bridge between the earlier (quasi-) formal and subsequent informal dialectical theories, and is explicitly acknowledged as a major influence by the Pragma-dialectical theory, the brainchild of Frans van Eemeren and Rob Grootendorst (1984). Rather than beginning from a logical or epistemological perspective they start with the role of argumentation in overcoming interpersonal disagreements. The Pragma-dialecticians propose that inter-personal argumentation can be analysed as two-party-discussions having four analytical stages: a confrontation stage in which the participants become aware of the content of their disagreement; an opening stage in which the parties agree (most likely implicitly) to shared starting points and a set of rules to govern the ensuing discussion; an argumentation stage wherein arguments and doubts about arguments are expressed and recognized; and a final stage in which a decision about the initial disagreement is made, if possible, based on what happened in the argumentation stage.

The Pragma-dialectical theory stipulates a normative ideal of a critical discussion which serves both as a guide to the reconstruction of natural language argumentation, as well as a standard for the evaluation of the analysed product of reconstruction. A set of ten rules has been proposed as constitutive of the critical-discussion ideal, and the proponents of the theory believe that rational arguers would accept them. If followed by both parties to the disagreement, the rules constrain the argumentation decision procedure such that any resolution reached will be deemed reasonable, and “every violation of any of the rules of the discussion procedure for conducting a critical discussion” will be a fallacy (2004, 175). The rules range over all the four stages of argumentation: at the confrontation stage there is a rule which says one may not prevent the other party from expressing their view; for the argumentation stage there is a rule which requires argumentation to be logically strong and in accord with one or another of three general argumentation schemes; at the closing stage there is a rule that the participants themselves are to decide which party was successful based on the quality of the argumentation they have made: if the proponent carries the day, the opponent should acknowledge it, and vice versa .

The Pragma-dialectical theory proposes that each of the core fallacies can be assigned a place as a violation of one of the rules of a critical discussion. For example, the ad baculum fallacy is a form of intimidation that violates the rule that one may not attempt to prevent one’s discussion partner from expressing their views; equivocation is a violation of the rule that formulations in arguments must be clear and unambiguous; post hoc ergo propter hoc violates the rule that arguments must be instances of schemes correctly applied. Moreover, on this theory, since any rule violation is to count as a fallacy this allows for the possibility that there may be hitherto unrecognized “new fallacies.” Among those proposed are declaring a standpoint sacrosanct because that breaks the rule against the freedom to criticize points of view, and evading the burden of proof which breaks the rule that you must defend your standpoint if asked to do so (see van Eemeren 2010, 194).

Clearly not all the rules of critical discussions apply directly to arguments. Some govern other goal-frustrating moves which arguers can make in the course of settling a difference of opinion, such as mis-allocating the burden of proof, asking irrelevant questions, suppressing a point of view, or failing to clarify the meaning of one’s argumentation. In short, the Pragma-dialectical rules of a critical discussion are not just rules of logic or epistemology, but rules of conduct for rational discussants, making the theory more like a moral code than a set of logical principles. Accordingly, this approach to fallacies rejects all three of the necessary conditions of SDF: a fallacy need not be an argument, thus the invalidity condition will not apply either, and the appearance condition is excluded because of its subjective character (Van Eemeren and Grootendorst 2004, 175).

The Pragma-dialectical analysis of fallacies as rule-breakings in a procedure for overcoming disagreements has recently been expanded to take account of the rhetorical dimension of argumentation. Pragma-dialectics takes the rhetorical dimension to stem from an arguer’s wish to have their view accepted which leads dialoguers to engage in strategic maneuvering vis-à-vis their dialogue partners. However, this desire must be put in balance with the dialectical requirement of being reasonable; that is, staying within the bounds of the normative demands of critical discussions. The ways of strategic maneuvering identified are basically three: topic selection, audience orientation, and the selection of presentational devices, and these can be effectively deployed at each stage of argumentation (Van Eemeren 2010, 94). “All derailments of strategic maneuvering are fallacies,” writes van Eemeren (2010, 198), “in the sense that they violate one or more of the rules for critical discussion and all fallacies can be viewed as derailments of strategic maneuvering.” This means that all fallacies are ultimately attributable to the rhetorical dimension of argumentation since, in this model, strategic maneuvering is the entry of rhetoric into argumentation discussions. “Because each fallacy has, in principle, sound counterparts that are manifestations of the same mode of strategic maneuvering” it may not appear to be a fallacy and it “may pass unnoticed” (Van Eemeren 2010, 199). Nevertheless, Pragma-dialectics prefers to keep the appearance condition outside the definition of ‘fallacy’, treating the seeming goodness of fallacies as a sometime co-incidental property, rather than an essential one.

Although the Pragma-dialectical theory continues to evolve into a more detailed and comprehensive understanding of argumentation (van Eemeren, 2018, ch. 8), it maintains that the model of a critical discussion can be used for argument appraisal across the various fields in which argumentation takes place such as the legal, the political, the interpersonal, etc. Each of the fields has developed its own stylized kind of discourse where different genres of argumentation are favoured (adjudication, deliberation, mediation, etc.), but the reasonableness of arguments in any of the fields will depend on how well they accord with the model of a critical discussion. This approach has been challenged by Douglas Walton who has written more about fallacies and fallacy theory than anyone else. He has published individual monographs on many of the well-known fallacies, among them, Begging the Question (1991), Slippery Slope Arguments (1992), Ad Hominem Arguments (1998), and a comprehensive work on fallacy theory, A Pragmatic Theory of Fallacy (1995). Over the years his views have evolved. He has referred to his theory as “the Pragmatic theory,” and like the Pragma-dialectical theory it has a dialectical/dialogical basis; however, Walton envisions a number of distinct normative dialectical frameworks (persuasion dialogue, inquiry dialogue, negotiation dialogue, etc.) rather than the single model of a critical discussion proposed by Pragma-dialectics. Postulating different kinds of dialogues with different starting points and different goals, thinks Walton, will bring argumentation into closer contact with argumentation reality. At one point Walton had the idea that fallacies happened when there was an illicit shift from one kind of a dialogue to another (1995, 118–23), for example, using arguments appropriate for a negotiation dialogue in a persuasion dialogue, but more recently he has turned to other ways of explicating fallacies.

Although Walton recognizes the class of formal fallacies, his main interest is in informal fallacies, especially the ones associated with argumentation schemes. The idea of an argumentation scheme is central to Walton’s theory. Schemes are patterns of commonly used kinds of defeasible reasoning/argumentation such as appeals to expert opinion and ad hominem arguments. Schemes do not identify fallacies but rather argument kinds that are sometimes used fairly, and, other times, fallaciously. With each kind of scheme is associated a set of critical questions which guide us in deciding whether a given use of an argument is correct, weak or fallacious. So, if we consider:

$E$ is an expert in subject area $S$; $E$ asserts $p$ based on $E$’s knowledge of $S$; So, $p$.

to be the scheme for the appeal-to-expertise kind of argument, [ 8 ] then there will be a question for each premise: Is $E$ really an expert in $S$? Did $E$ say $p$ when s/he was acting in her/his professional capacity? (… or did s/he blurt it out while drunk at an association party?). If the answer to both questions is Yes, then the argument creates a presumption for the conclusion—but not a guarantee, for the reasoning is defeasible: other information may come to light that will override the presumption. If one of the questions cannot be answered clearly this is an indication that the argument is weak, and answering No to either of the two questions cancels the presumption for the conclusion, i.e., makes the argument into a bad argument from expert opinion. If the bad argument has “a semblance of correctness about it in [the] context, and poses a serious obstacle to the realization of the goal of the dialog,” then it is a fallacy (2011, 380). [ 9 ]

The definition of fallacy Walton proposes (1995, 255) has five parts. A fallacy:

an argument (or at least something that purports to be an argument) that
falls short of some standard of correctness;
is used in a context of dialogue;
has a semblance of correctness about it; and
poses a serious problem to the realization of the goal of the dialogue.

Here we find that Walton has relaxed two of the necessary conditions of SDF. Purporting to be an argument is enough (it doesn’t really have to be an argument), while falling short of a standard (one that will vary with the kind of dialogue under consideration) replaces the invalidity condition. However, the appearance condition, here expressed as fallacies having a semblance of correctness about them, remains in full force. The two extra conditions added to fallacy are that they occur only in contexts of dialogue and that they frustrate the realization of the goal of the kind of dialogue in which they occur. In insisting on this dialogical dimension, Walton is in full sympathy with those who think that fallacies can only be rightly analysed within a dialectical framework similar to the ones Aristotle originally studied, and later better defined by Hamblin and Lorenzen. Walton volunteers a shorter version of the definition of a fallacy as “a deceptively bad argument that impedes the progress of a dialogue” (1995, 256).

Walton divides fallacies into two kinds: paralogisms and sophisms. A paralogism is “the type of fallacy in which an error of reasoning is typically committed by failing to meet some necessary requirement of an argumentation scheme” whereas “the sophism type of fallacy is a sophistical tactic used to try to unfairly get the best of a speech partner in an exchange of arguments” (2010, 171; see also 1995, 254). Paralogisms are instances of identifiable argumentation schemes, but sophisms are not. The latter are associated more with infringing a reasonable expectation of dialogue than with failing some standard of argument (2011, 385; 2010, 175). A further distinction is drawn between arguments used intentionally to deceive and arguments that merely break a maxim of argumentation unintentionally. The former count as fallacies; the latter, less condemnable, are blunders (1995, 235).

Among the informal paralogisms Walton includes: ad hominem , ad populum , ad misericordiam , ad ignorantiam , ad verecundiam , slippery slope, false cause, straw man, argument from consequences, faulty analogy, composition and division. In the category of sophisms he places ad baculum , complex question, begging the question, hasty generalization, ignoratio elenchi , equivocation, amphiboly, accent, and secundum quid . He also has a class of formal fallacies very much the same as those identified by Whately and Copi. The largest class in Walton’s classification is the one associated with argumentation schemes and ad -arguments, and these are the ones that he considers to be the most central fallacies. Nearly all the Aristotelian fallacies included find themselves relegated to the less studied categories of sophisms. Taking a long look at the history of fallacies, then, we find that the Aristotelian fallacies are no longer of central importance. The main focus of interest is now the list of fallacies that have grown out of Locke’s creation of the ad -argument genre.

Another recent approach comes from virtue argumentation theory (modelled on virtue epistemology). Virtue argumentation theory is characterized by a distinct set of virtues thought to be essential to good argumentation: willingness to engage in argumentation, willingness to listen to others and willingness to modify one’s own position (see, e.g., Cohen 2009). These may be supplemented with epistemic virtues and even in some cases moral virtues. Although virtues and vices are dispositions of arguers and fallacies are arguments, it is claimed that good argumentation generally results from the influence of argumentation virtues and bad argumentation (including the fallacies) arise because of the vices of arguers.

Taking the Aristotelian view that virtues are a mean between opposite kinds of vices, fallacious arguments can be seen as resulting from arguers moving in one or another direction away from a mean of good argumentation. Aberdein (2013, 2016) especially has developed this model for understanding many of the fallacies. We can illustrate the view by considering appeals to expertise: the associated vices might be too little respect for reliable authorities at one extreme and too much deference to authorities at the other extreme. Aberdein develops the fallacies-as-argumentation-vices analysis in some detail for other of the ad-arguments and sketches how it might be applied to the other core fallacies, suggesting it can profitably be extended to all of them.

All the fallacies, it is claimed, can be fitted in somewhere in the classification of argumentational vices, but the converse is not true although it is possible to bring to light other shortcomings to which we may fall prey in argumentation. Another aspect of the theory is that it distributes argumentation vices among both senders and audiences. Speakers may infect their arguments with vices when they are, for example, closed minded or lack respect for persons, and audiences can contribute to fallaciousness by letting their receptivity be influenced by naïvety, an over-reliance on common sense, or an unfounded bias against a speaker. Perhaps the development of the virtue argumentation theory approach to fallacies provides a supplement to Mill’s theory of fallacies. He distinguished (1891, V, i, 3) what he called the moral (dispositional) and intellectual causes of fallacy. The study of the argumentative vices envisioned above seems best included under the moral study of fallacies as the vices can be taken to be the presdisposing causes to commit intellectual mistakes, i.e., misevaluations of the weight of evidence.

Finocchiaro (2023, 24) has introduced a distinction between ground-level arguments and meta-argument. The former are about natural phenomena, historical events, human actions, abstract entities, etc. and the latter are about one or more arguments, or about argumentation in general. When we justify our judgments that an argument, x , has committed a fallacy we are making a meta-argument about x . Finocchiaro uses the fallacy of composition as an example saying it is primarily a meta-argument concept used to assess an argument at the ground-level as a fallacy.

Akin and Casey take this line of analysis further, arguing that there are indeed fallacies best understood as fallacies of meta-argumentation. They have studied three of them: the straw man fallacy (2022a), bothsiderism (2022b), and what they call the free-speech fallacy (2023). These are all fallacies that may occur in the process of argumentation, i.e., exchanges between arguers. On this view, straw man fallacies happen when someone in the course of argumentation inaccurately and unfavourable distorts a ground-level argument in an attempt to refute it or discredit its source. In the case of bothsiderism, there are conflicting arguments each drawing on prima facie evidence. This can lead to the meta-argument that the truth lies somewhere in the middle between the opposed ground-level conclusions. This is considered a fallacy because purported contrary evidence noticed at the meta-level is insufficient reason to abandon both the ground-level conclusions in favour of a compromise. Cases where people claim their right to free speech is infringed, say Akin and Casey, also admit of the possibility of meta-argumentation fallacies. One of the ways is when criticism of a view is mistaken for censorship of that view; another is when parties are excluded from participation in a discussion for good reasons such as lack of qualifications or holding repugnant social views. From their exclusion they may make the meta-argument that the outcome of the discussion is epistemically unwarranted because of evidence not taken into consideration, or they may even think that the fact that their view was excluded is a sign that it has merit its opponents would rather not admit. The authors say that these kinds of mistakes are meta-argumentation fallacies and anticipate that there are more of them waiting for analysis.

4. Current issues in fallacy theory

A question that continues to dog fallacy theory is how we are to conceive of fallacies. There would be advantages to having a unified theory of fallacies. It would give us a systematic way of demarcating fallacies and other kinds of mistakes; it would give us a framework for justifying fallacy judgments, and it would give us a sense of the place of fallacies in our larger conceptual schemes. Some general definition of ‘fallacy’ is wanted but the desire is frustrated because there is disagreement about the identity of fallacies. Are they inferential, logical, epistemic or dialectical mistakes? Some authors insist that they are all of one kind: Biro and Siegel, for example, that they are epistemic, and Pragma-dialectics that they are dialectical. There are reasons to think that all fallacies do not easily fit into one category.

Together the Sophistical Refutations and Locke’s Essay are the dual sources of our inheritance of fallacies. However, for four reasons they make for uneasy bedfellows. First, the ad fallacies seem to have a built-in dialectical character, which, it can be argued, Aristotle’s fallacies do not have (they are not sophistical refutations but are in sophistical refutations). Second, Aristotle’s fallacies are logical mistakes: they have no appropriate employment outside eristic argumentation whereas the ad -fallacies are instances of ad -arguments, often appropriately used in dialogues. Third, the appearance condition is part of the Aristotelian inheritance but it is not intimately connected with the ad -fallacies tradition. A fourth reason that contributes to the tension between the Aristotelian and Lockean traditions in fallacies is that the former grew out of philosophical problems, largely what are logical and metaphysical puzzles (consider the many examples in Sophistical Refutations ), whereas the ad -fallacies are more geared to social and political topics of popular concern, the subject matter that most intrigues modern researchers on fallacy theory.

As we look back over our survey we cannot help but observe that fallacies have been identified in relation to some ideal or model of good arguments, good argumentation, or rationality. Aristotle’s fallacies are shortcomings of his ideal of deduction and proof, extended to contexts of refutation. The fallacies listed by Mill are errors of reasoning in a comprehensive model that includes both deduction and induction. Those who have defended SDF as the correct definition of ‘fallacy’ [ 10 ] take logic simpliciter or deductive validity as the ideal of rationality. Informal logicians view fallacies as failures to satisfy the criteria of what they consider to be a cogent argument. Defenders of the epistemic approach to fallacies see them as shortfalls of the standards of knowledge-generating arguments. Finally, those who are concerned with how we are to overcome our disagreements in a reasonable way will see fallacies as failures in relation to ideals of debate or critical discussions.

The standard treatment of the core fallacies has not emerged from a single conception of good argument or reasonableness but rather, like much of our unsystematic knowledge, has grown as a hodgepodge collection of items, proposed at various time and from different perspectives, that continues to draw our attention, even as the standards that originally brought a given fallacy to light are abandoned or absorbed into newer models of rationality. Hence, there is no single conception of good argument or argumentation to be discovered behind the core fallacies, and any attempt to force them all into a single framework, must take efforts to avoid distorting the character originally attributed to each of them.

From Aristotle to Mill the appearance condition was an essential part of the conception of fallacies. However, some of the new, post-Hamblin, scholars have either ignored it (Finocchiaro, Biro and Siegel) or rejected it because appearances can vary from person to person, thus making the same argument a fallacy for the one who is taken in by the appearance, and not a fallacy for the one who sees past the appearances. This is unsatisfactory for those who think that arguments are either fallacies or not. Appearances, it is also argued, have no place in logical or scientific theories because they belong to psychology (van Eemeren and Grootendorst, 2004). But Walton (e.g., 2010) continues to consider appearances an essential part of fallacies as does Powers (1995, 300) who insists that fallacies must “have an appearance, however quickly seen through, of being valid.” If the mistake in an argument is not masked by an ambiguity that gives it the appearance of being a better argument than it really is, Powers denies it is a fallacy.

The appearance condition of fallacies serves at least two purposes. First, it can be part of explanations of why reasonable people make mistakes in arguments or argumentation: it may be due in part to an argument’s appearing to be better than it really is. Second, it serves to divide mistakes into two groups: those which are trivial or the result of carelessness (for which there is no cure other than paying better attention), and those which we need to learn to detect through an increased awareness of their seductive nature. Without the appearance condition, it can be argued, no division can be made between these two kinds of errors: either there are no fallacies or all mistakes in argument and/or argumentation are fallacies; a conclusion that some are willing to accept, but which runs contrary to tradition. One can also respond that there is an alternative to using the appearance condition as the demarcation property between fallacies and casual mistakes, namely, frequency. Fallacies are those mistakes we must learn to guard against because they occur with noticeable frequency. To this it may be answered that ‘noticeable frequency’ is vague, and is perhaps best explained by the appearance condition.

Oswald and Herman (2020) explain the possibility that an argument might seem better than it really is by appealing to both cognitive and rhetorical factors. The cognitive factor is that the information set of a sender making a fallacious argument might be greater than the information set of an argument receiver, thus potentially putting the receiver in a position to be deceived. Persuasive skills can exploit such a difference in information sets by manipulating the relevant contextual evidence; that is, by bringing forward what favours the fallacious argument and holding back critical factors against it. The receiver may thus be taken in by a fallacy because of the way the argument was presented to them. Hansen (2023) considers the causal factors that might lead to misperception of bad arguments as good arguments. They include structural properties of arguments, perceptual perspectives, the social atmosphere in which the arguments are presented, and misperceptions due to abnormalities in the argument receiver.

On the more practical level, there continues to be discussion about the value of teaching the fallacies to students. Is it an effective way for them to learn to reason well and to avoid bad arguments? One reason to think that it is not effective is that the list of fallacies is not complete, and that even if the group of core fallacies was extended to incorporate other fallacies we thought worth including, we could still not be sure that we had a complete prophylactic against bad arguments. Hence, we are better off teaching the positive criteria for good arguments/ argumentation which give us a fuller set of guidelines for good reasoning. But some (Pragma-dialectics and Johnson and Blair) do think that their stock of fallacies is a complete guard against errors because they have specified a full set of necessary conditions for good arguments/argumentation and they hold that fallacies are just failures to meet one of these conditions.

Another consideration about the value of the fallacies approach to teaching good reasoning is that it tends to make students overly critical and lead them to see fallacies where there are not any; hence, it is maintained we could better advance the instilling of critical thinking skills by teaching the positive criteria of good reasoning and arguments (Hitchcock, 1995). In response to this view, it is argued that, if the fallacies are taught in a non-perfunctory way which includes the explanations of why they are fallacies—which normative standards they transgress—then a course taught around the core fallacies can be effective in instilling good reasoning skills (Blair 1995).

In more recent work, Blair (2023) has moved closer to Hitchcock’s recommendation that fallacies not be taught in introductory level courses, but his reason is that the study of fallacies has become so complex with many dimensions and overlapping approaches that it has become a subject too challenging for undergraduate students; moreover, few instructors are familiar with the extensive literature that has developed on fallacies. Hitchcock (2023) has followed up his earlier article with a study of six of the most widely used textbooks (each having at least ten editions) that have a section on the fallacies and asked whether they have benefitted from Hamblin’s (1970) critique of the standard treatment (see above section 3.1). He finds that by the standard implicit in Hamblin’s critique, there has been little improvement in the analysis and presentation of fallacies in those textbooks.

Biases are “inclinations to see things one way rather than another,” explains Nickerson (2021, 208). He reviews the literature on biases that can affect reasoning, discussing both the motivational and cognitive factors that may lead to the presence of biases (ch. 7). Like fallacies, there is no fixed definitive list, and the individuation of biases largely depends on the goal of our inquiries. Correia (2011) has taken Mill’s insight that biases are predisposing causes of fallacies a step further by connecting identifiable biases with particular fallacies. Biases can influence the committing of fallacies even where there is no intent to be deceptive, he observes. Taking biases to be “systematic errors that invariably distort the subject’s reasoning and judgment,” the picture drawn is that particular biases are activated by desires and emotions (motivated reasoning) and once they are in play, they negatively affect the fair evaluation of evidence. Thus, for example, the “focussing illusion” bias inclines a person to focus on just a part of the evidence available, ignoring or denying evidence that might lead in another direction. Correia (2011, 118) links this bias to the fallacies of hasty generalization and straw man, suggesting that it is our desire to be right that activates the bias to focus more on positive or negative evidence, as the case may be. Other biases he links to other fallacies.

Thagard (2011) is more concerned to stress the differences between fallacies and biases than to find connections between them. He claims that the model of reasoning articulated by informal logic is not a good fit with the way that people actually reason and that only a few of the fallacies are relevant to the kinds of mistakes people actually make. Thagard’s argument depends on his distinction between argument and inference. Arguments, and fallacies, he takes to be serial and linguistic, but inferences are brain activities and are characterized as parallel and multi-modal. By “parallel” is meant that the brain carries out different processes simultaneously, and by “multi-modal” that the brain uses non-linguistic and emotional, as well as linguistic representations in inferring. Biases (inferential error tendencies) can unconsciously affect inferring. “Motivated inference,” for example, “involves selective recruitment and assessment of evidence based on unconscious processes that are driven by emotional considerations of goals rather than purely cognitive reasoning” (2011, 156). Thagard volunteers a list of more than fifty of these inferential error tendencies. Because motivated inferences result from unconscious mental processes rather than explicit reasoning, the errors in inferences cannot be exposed simply by identifying a fallacy in a reconstructed argument. Dealing with biases requires identification of both conscious and unconscious goals of arguers, goals that can figure in explanations of why they incline to particular biases. “Overcoming people’s motivated inferences,” Thagard concludes, “is therefore more akin to psychotherapy than informal logic” (157), and the importance of fallacies is accordingly marginalized.

In response to these findings, one can admit their relevance to the pedagogy of critical thinking but still recall the distinction between what causes mistakes and what the mistakes are. The analysis of fallacies belongs to the normative study of arguments and argumentation, and to give an account of what the fallacy in a given case is will involve making reference to some relevant norm of argument or argumentation. It will be an explanation of what the mistake in the argument is. Biases are relevant to understanding why people commit fallacies, and how we are to help them get past them, but they do not help us understand what the fallacy-mistakes are in the first place—this is not a question of psychology. Continued research at this intersection of interests will hopefully shed more light on both biases and fallacies.

Aberdein, A., 2013, “Fallacy and argumentational vice,” Ontario Society for the Study of Argumentation (OSSA Conference Archive: OSSA 10), available online .
–––, 2016, “The vices of argument,” Topoi , 25: 413–22.
Akin, S.F., and J. Casey, 2022a, Straw Man Arguments: A Study in Fallacy Theory , London: Bloomsbury.
–––, 2022b, “Bothsiderism,” Argumentation , 36: 249–68.
–––, 2023, “Free speech fallacies as meta-argumentative errors,” Argumentation , 37: 295–305.
Aristotle, Categories , H.P. Cooke (trans.), Cambridge, MA: Harvard University Press, 1938.
–––, On Sophistical Refutations , E. S. Forster (trans.), Cambridge, MA: Harvard University Press, 1955.
–––, Posterior Analytics , H. Tredennick (trans.), Cambridge, MA: Harvard University Press, 1960.
–––, Topics , Books I and VIII , R. Smith (trans.), Oxford: Clarendon Press, 1997.
Arnauld, A., and P. Nicole, 1685, Logic, or the Art of Thinking , 5 th edition, J. V. Buroker (trans.), Cambridge: Cambridge University Press, 1996.
Bachman, J., 1995, “Appeal to authority,” in Hansen and Pinto, 1995, pp. 274–86.
Bacon, F., 1620, The New Organon , Indianapolis: Bobbs-Merrill, 1960.
Barth, E. M., and J. L. Martens, 1977, “ Argumentum ad hominem , from chaos to formal dialectic,” Logique et Analyse , 20: 76–96.
Bentham, J., 1824, The Handbook of Political Fallacies , page references to reprint, H. A. Larrabee (ed.), New York: Harper and Brothers, 1962.
Biro, J., 1977, “Rescuing ‘begging the question’,” Metaphilosophy , 8: 257–71.
Biro, J., and H. Siegel, 1992, “Normativity, argumentation and an epistemic theory of fallacies,” in Frans H. van Eemeren, et al., editors, Argumentation Illuminated , Amsterdam: Sic Sat, pp. 85–103.
–––, 1997, “Epistemic normativity, argumentation and fallacies,” Argumentation , 11: 277–293.
–––, 2006, “In defence of the objective epistemic approach to argumentation,” Informal Logic , 26: 91–102.
Blair, J. A., 1995, “The place of teaching informal fallacies in teaching reasoning skills or critical thinking,” in Hansen and Pinto 1995, pp. 328–38.
–––, 2023, “Teaching the fallacies,” Argumentation , 37: 247–251.
Brinton, A., 1995, “The ad hominem ,” in Hansen and Pinto 1995, pp. 213–22.
Churchill, R. P., 1986, Becoming Logical , New York: St Martin’s Press.
Cohen, D.H., 2009, “Keeping an open mind and having a sense of proportion as virtues in argumentation,” Cogency , 1: 49–64.
Copi, I. M., 1961, Introduction to Logic , (2 nd ed.), New York: Macmillan.
Corcoran, J., 1974, “Remarks on Stoic deduction,” in J. Corcoran (ed.), Ancient Logic and its Modern Interpretations , Dordrecht: Reidel, pp. 169–81.
Corner, A., U. Hahn, and M. Oaksford, 2006, “The slippery slope argument—probability, utility and category reappraisal,” Proceedings of the Annual Meeting of the Cognitive Science Society , 28: 1145–1150, available online .
Correia, V., 2011, “Biases and fallacies: The role of motivated irrationality in fallacious reasoning,” Cogency , 3: 107–26.
Finocchiaro, M. A., 1974, “The concept of ad hominem argument in Galileo and Locke,” Philosophical Forum , 5: 394–404; page references are to Finocchiaro 2005, pp. 329–39.
–––, 1981, “Fallacies and the evaluation of reasoning,” American Philosophical Quarterly 18: 13–22; page references are to Finocchiaro 2005, pp. 109–27.
–––, 1987, “Six types of fallaciousness: towards a realistic theory of logical criticism,” Argumentation 1: 263–82; page references are to Finocchiaro 2005, pp. 128–47.
–––, 2005, Arguments about Arguments . Cambridge: Cambridge University Press.
–––, 2023, The Fallacy of Composition: Critical Reviews, ConceptualAanalyses, and Case Studies , London: College Publications.
Freeman, J. B., 1988, Thinking Logically: Basic Concepts for Reasoning , Englewood Cliffs: Prentice-Hall.
–––, 1995, “The appeal to popularity and presumption by common knowledge,” in Hansen and Pinto 1995, pp. 265–73.
Goodwin, J., 1998, “Forms of authority,” Argumentation , 12: 267–80.
Govier, T., 1982, “What’s wrong with slippery slope fallacies?” Canadian Journal of Philosophy , 12: 303–16.
–––, 1987, “Four reasons there are no fallacies?” in Problems in Argument Analysis and Evaluation , Dordrecht: Foris; page references to reprint as “Reply to Massey” in Hansen and Pinto 1995, pp. 172–80.
–––, 1988, A Practical Study of Argument , 2nd edition, Belmont: Wadsworth.
Grootendorst, R., 1997, “Jeremy Bentham’s Handbook of Political Fallacies ,” in Historical Foundations of Informal Logic , D. Walton and A. Brinton (eds.), Aldershot: Ashgate, pp. 114–24.
Hahn, U., and M. Oaksford, 2006a, “A normative theory of argument strength,” Informal Logic , 26: 1–24.
–––, 2006b, “A Bayesian approach to informal argument fallacies,” Synthese , 152: 207–236.
Hamblin, C. L., 1970, Fallacies , London: Methuen.
Hansen, H. V., 2002, “The straw thing of fallacy theory: the standard definition of ‘fallacy’,” Argumentation , 16: 134–55.
–––, 2023, “Committing fallacies and the appearance condition,” Argumentation , 37: 253–267.
–––, and R. C. Pinto (eds.), 1995, Fallacies: Classical and Contemporary Readings , University Park: Penn State Press.
Hintikka, J., 1987, “The fallacy of fallacies,” Argumentation , 1: 211–38.
–––, 1997, “What was Aristotle doing in his early logic, anyway? A reply to Woods and Hansen,” Synthese , 113: 241–49.
Hitchcock, D., 1995, “Do fallacies have a place in the teaching of reasoning skills or critical thinking?” in Hansen and Pinto 1995, pp. 319–27.
–––, 2000, “Fallacies and formal logic in Aristotle,” History and Philosophy of Logic , 21: 2017–21.
–––, 2023. “Textbook treatments of fallacies,” Argumentation , 37: 233–245.
Irwin, T., and G. Fine, 1996, Aristotle, Introductory Readings , Indianapolis: Hackett.
–––, 1987, “The blaze of her splendors: Suggestions about revitalizing fallacy theory,” Argumentation , 1: 239–53; page references to reprint in Hansen and Pinto 1995, pp. 107–19.
Johnson, R., and J. A. Blair, 1993, Logical Self-Defence , 3 rd ed., Toronto: McGraw-Hill Ryerson.
Johnstone, H. W., Jr., 1952, “Philosophy and argumentum ad hominem ,” Journal of Philosophy , 49: 489–98.
Kahane, H., 1971, Logic and Contemporary Rhetoric , Belmont: Wadsworth.
Korb, K., 2003, “Bayesian informal logic and fallacy,” Informal Logic , 23: 41–70.
Krabbe, E. C. W., 1995, “Appeal to ignorance,” in Hansen and Pinto 1995, pp. 251–64.
Locke, J., 1690, An Essay Concerning Human Understanding . Many editions.
Lorenzen, P., 1969, Normative Logic and Ethics , Mannheim: Bibliographisches Institut; 2nd annotated edition, 1984.
Massey, G. J., 1981, “The fallacy behind fallacies,” Midwest Studies in Philosophy , 6: 489–500; page references are to reprint in Hansen and Pinto 1995, pp. 159–71.
Mates, B., 1965, Elementary Logic , Oxford: Oxford University Press.
Mill, J. S., 1891, A System of Logic, Ratiocinative and Inductive , 8 th edition, New York: Harper and Brothers; first edition 1843.
Nickerson, R.S., 2021, Argumentation: The Art of Persuasion , Cambridge: Cambridge University Press.
Nuchelmans, G., 1993, “On the fourfold root of argumentum ad hominem ,” in E. C. W. Krabbe, R. J. Dalitz, and P. A. Smit (eds.), Empirical Logic and Public Debate , Amsterdam: Rodopi, pp. 37–47.
Oswald, S., and T. Herman, 2020, “Give the standard treatment of fallacies a chance! Cognitive and rhetorical insights into fallacy processing,” in F.H. van Eemeren and B. Garssen (eds.), From Argument Schemes to Argumentative Relations in the Wild , Cham: Springer, pp. 41–62.
Pinto, R. C., 1995, Post hoc, ergo propter hoc , in Hansen and Pinto, pp. 302–11.
Powers, L., 1995, “Equivocation,” in Hansen and Pinto 1995, pp. 287–301.
Rosen, F., 2006, “The philosophy of error and liberty of thought: J. S. Mill on logical fallacies,” Informal Logic , 26: 121–47.
Rudanko, J., 2021, Fallacies and Free Speech , New York: Palgrave MacMillan.
Salmon, W., 1963, Logic , Englewood-Cliffs: Prentice-Hall.
Schreiber, S. G., 2003, Aristotle on False Reasoning , Albany: State University of New York Press.
Sidgwick, A., 1878, “The negative character of logic,” Mind , 3: 350–357.
––, 1884, Fallacies: A View of Logic from the Practical Side , New York: D. Appleton and Co.
Smith, R., 1997, “Commentary,” Aristotle: Topics, Books I and VIII , Oxford: Clarendon Press.
Thagard, P., 2011, “Critical thinking and informal logic: neuropsychological perspectives,” Informal Logic , 31: 152–70.
Tindale, C. W., 1996, “Fallacies in transition: An assessment of the Pragma-dialectical perspective,” Informal Logic , 18: 17–33.
–––, 2007, “On Fallacy,” in Reason Reclaimed: Essays in Honor of J. Anthony Blair and Ralph H. Johnson , H.V. Hansen and R. C. Pinto (eds.), Newport News: Vale Press, pp. 155–70.
Van Eemeren, F. H., 2010, Strategic Maneuvering in Argumentative Discourse , Amsterdam: John Benjamins.
–––, and Rob Grootendorst, 1984, Speech Acts in Argumentative Discussions , Dordrecht: Foris.
–––, 1992, Argumentation, Communication and Fallacies , Hillsdale: Erlbaum.
–––, 2004, A Systematic Theory of Argumentation , Cambridge: Cambridge University Press.
___, 2018, Argumentation Theory: A Practical Dialectical Perspective , Cham: Springer.
Walton, D. N., 1991, Begging the Question , New York: Greenwood.
–––, 1995, A Pragmatic Theory of Fallacies , Tuscaloosa: University of Alabama Press.
–––, 1998, Ad hominem arguments , Tuscaloosa, University of Alabama Press.
–––, 2010, “Why fallacies appear to be better arguments than they are,” Informal Logic , 30: 159–84.
–––, 2011, “Defeasible reasoning and informal fallacies,” Synthese , 179: 377–407.
Watts, I., 1796, Logick: or, the Right Use of Reason , 2 nd edition; page references to reprint, New York: Garland, 1984.
Whately, R., 1875, Elements of Logic , 9 th ed., London: Longmans, Green and Company; first edition 1826.
Woods, J., 1992, “Who cares about the fallacies?” in Argumentation Illuminated , F. H. van Eemeren, et al. (eds.), Amsterdam: SicSat, pp. 23–48.
–––, 2013, Errors of Reasoning: Naturalizing the Logic of Inference , London: College Publications.
–––, and H. V. Hansen, 1997, “Hintikka on Aristotle’s fallacies,” Synthese , 113: 217–39.
–––, 2001, “The subtleties of Aristotle on non-cause,” Logique et analyse , 176: 395–415.
Woods, J., and D. N. Walton, 1989, Fallacies: Selected Papers, 1972–1982 , Dordrecht: Foris.
Wreen, M., 1989, “A bolt of fear,” Philosophy and Rhetoric , 22: 131–40.

How to cite this entry . Preview the PDF version of this entry at the Friends of the SEP Society . Look up topics and thinkers related to this entry at the Internet Philosophy Ontology Project (InPhO). Enhanced bibliography for this entry at PhilPapers , with links to its database.

Curtis, Gary N., Fallacy Files
Dowden, Bradley, Fallacies , entry in the Internet Encyclopedia of Philosophy .
Hansen, H.V., and C. Fioret, 2016. A searchable bibliography of fallacies—2016 , Informal Logic , 36: 432–72.
Informal Logic , an open-access journal.
Labossiere, Michael C., Fallacies , hosted by The Nizkor Project.
RAIL , a blog about Reasoning, Argumentation, and Informal Logic.

logic: informal | relativism

Acknowledgments

The author would like to thank the executive and subject editors who suggested a way to improve the discussion of begging the question .

Accessibility

Support SEP

Mirror sites.

View this site from another server:

Info about mirror sites

Library of Congress Catalog Data: ISSN 1095-5054

Passion doesn’t always come easily. Discover your inner drive and find your true purpose in life.

From learning how to be your best self to navigating life’s everyday challenges.

Discover peace within today’s chaos. Take a moment to notice what’s happening now.

Gain inspiration from the lives of celebrities. Explore their stories for motivation and insight into achieving your dreams.

Where ordinary people become extraordinary, inspiring us all to make a difference.

Take a break with the most inspirational movies, TV shows, and books we have come across.

From being a better partner to interacting with a coworker, learn how to deepen your connections.

Take a look at the latest diet and exercise trends coming out. So while you're working hard, you're also working smart.

Sleep may be the most powerful tool in our well-being arsenal. So why is it so difficult?

Challenges can stem from distractions, lack of focus, or unclear goals. These strategies can help overcome daily obstacles.

Unlocking your creativity can help every aspect of your life, from innovation to problem-solving to personal growth.

How do you view wealth? Learn new insights, tools and strategies for a better relationship with your money.

9 Logical Fallacies That You Need to Know To Master Critical Thinking

When you learn about logic, language becomes a game you can win..

William James, who was known as the grandfather of psychology, once said: “A great many people think they are thinking when they are merely rearranging their prejudices.” All of us think, every day. But there’s a difference between thinking for thinking’s sake, and thinking in a critical way. Deliberate, controlled, and reasonable thinking is rare.

There are multiple factors that are impairing people’s ability to think critically, from technology to changes in education. Some experts have speculated we’re approaching a crisis of critical thinking , with many students graduating “without the ability to construct a cohesive argument or identify a logical fallacy.”

RELATED: How to Tell if ‘Political Correctness’ Is Hurting Your Mental Health

That's a worrying trend, as critical thinking isn’t only an academic skill, but essential to living a high-functioning life. It’s the process by which to arrive at logical conclusions. And in through that process, logical fallacies are a significant hazard.

This article will explore logical fallacies in order to equip you with the knowledge on how to think in skillful ways, for the biggest benefits. As a result, you'll be able to detect deception of flawed logic, in others, and yourself. And you'll be equipped to think proper thoughts, rather than simply rearrange prejudices.

What Is a Logical Fallacy?

The study of logic originates back to the Greek philosopher Aristotle (384–322 b.c.e), who started to systematically identify and list logical fallacies. The origin of logic is linked to the Greek logos , which translates to language, reason, or discourse. Logical fallacies are errors of reason that invalidate an argument. The use of logical fallacies changes depending on a person’s intention. Although for many, they’re unintentional, others may deliberately use logical fallacies as a type of manipulative behavior .

Detecting logical fallacies is crucial to improve your level of critical thinking, to avoid deceit, and to spot poor reasoning; within yourself and others. The influential German philosopher Immanuel Kant once said; “All our knowledge begins with the senses, proceeds then to the understanding, and ends with reason. There is nothing higher than reason.”

RELATED: Fundamental Attribution Error: Definition & Examples

Throughout history, the world’s greatest thinkers have promoted the value of reasoning. Away from academia, reason is the ability to logically process information, and arrive at an accurate conclusion, in the quest for truth. Striving to be more reasonable or calm under pressure is a virtuous act. It’s a noble pursuit, one which in its nature will inspire your personal development, and allow you to become the best version of yourself.

Why Critical Thinking Is Important

It seems like humanity has never been so polarized, separated into different camps and stances; Democrats vs. Liberals, vegans vs. meat eaters, vaccinated vs. unvaccinated, pro-life vs. pro-choice. There’s nothing inherently wrong with thinking critically, and taking a stand. However, what is unusual is the tendency for people to lean into one extreme or the other, neglecting to explore gray areas or complexity.

Many of the positions people take are chosen for them. It takes a lot of effort to research a point of view. And even then, we’re faced with the challenge of information overload, fake news, conspiracy, and even credible news which is dismissed as conspiracy. Far from academic debates or politicians facing off during leadership races, the ability to share respectful dialogue is an essential part of understanding our place in the world, and maintaining human relationships.

The hot topics facing humanity aren’t going to be resolved by reactivity or over-emotionality . There should be room for all sorts of emotions to surface; it’s understandable to feel anger, grief, anxiety, etc, faced with global events. But critical thinking asks for a more reasoned, calm consideration, not getting completely carried away with emotions, but appealing to higher judgment.

Examples of When to Use Critical Thinking

It’s not always clear why critical thinking is so valuable. Isn’t it only useful for education, philosophy, science, or politics? Not quite. When applied appropriately, logic has a universal appeal in life. Examples include:

Problem-solving : “The problem is not that there are problems,” wrote psychiatrist Theodore Isaac Rubin, “the problem is expecting otherwise, and thinking that having problems is a problem.” Life is full of problems. Fortunately, that means life is full of opportunities to problem solve. Critical thinking is an essential problem-solving skill, from managing your time to organizing your finances.
Making optimal decisions : the more logical you are, and the less you fall into logical fallacies, the better your decision-making becomes . Decisions are the steps towards your goals, each decision making you closer to, or away from, what you really desire.
Understanding complex subjects : with attention spans reducing due to social media and technology, it’s becoming rare to take time to attempt to understand complex topics, away from repeating what others have said. Whether through self-study or to comprehend global events, critical thinking is essential to understand complexity.
Improving relationships : adding a dose of logic to your interactions will allow you to make better choices in relationships. Many “messy” forms of communication, from guilt-tripping to passive aggression, are illogical. By tapping into a more balanced point of view, you’ll better overcome conflict, argue your point (when necessary), or explain the way you feel.

The Most Common Logical Fallacies

When you begin to explore logical fallacies, language becomes a game. There’s a sense of having a cheat sheet in communication, understanding the underlying dynamics at play. Of course, it’s not as straightforward as a mechanical understanding — emotional intelligence, and non-verbal body language has a role to play, too. We’re humans, not computers. But gaining mastery of logic puts you ahead of the majority of people, and helps you avoid cognitive bias.

What’s more, most people fall into logical fallacies without being aware. Once you can detect these mechanisms, within yourself and with others, you’ll have an upper hand in many key areas of life, not least in a professional setting, or in any place you need to persuade or argue a point. The list is ever-growing and vast, but below are the most common logical fallacies to get the ball rolling:

1. Ad Hominem

Originating from a Latin phrase meaning “to the person,” ad hominem is an attack on the person, not the argument. This has a twofold impact — it deflects attention away from the validity of the argument, and second, it can provoke the person to enter a defensive mindset. If you’re aware of this fallacy, it can keep you from taking the bait, and instead keeping the focus on the argument.

Perhaps the most popular example of this in recent times is the viral interview between Jordan Peterson and Cathy Newman. Love him or hate him, Peterson is an embodiment of logic, sidestepping Newman’s ad hominem attacks and fallacies in a calm and controlled manner.

2. Red Herring

You might have heard of this phrase in the context of fiction: a red herring is an irrelevant piece of information thrown into the mix, in order to distract from other relevant details, commonly used in detective stories. In a political context, you might see a politician respond to criticism by talking about something positive they’ve done. For example, when asked why unemployment is so high, they may say “we’ve made a lot of effort to improve working conditions in certain areas.”

A popular type of red herring in modern discourse is "what aboutism," a form of counter-accusation. If the person mentioning unemployment is a fellow politician, the same politician may say: “what about unemployment rates when your party was in charge?”

3. Tu Quoque Fallacy

Closely related to the above, and in some ways, a mixture of the ad hominem and a red herring, is the tu quoque fallacy (pronounced tu-KWO-kway and originating from the Latin “you too”). This is a counter-accusation that accuses someone of hypocrisy. Rather than acknowledging what's been said, someone responds with a direct allegation. For example, if you’re in an argument and your partner raises their voice, you may bring that to their attention, only for them to say: “you raise your voice all the time!”.

4. Straw Man

The straw man logical fallacy is everywhere, especially in dialogue on hot-topic issues, because it's effective in shutting down someone else’s perspective. The person runs with someone’s point, exaggerates it, then attacks the exaggerated version — the straw man — seemingly in an appropriate way. For example, when your partner asks if you could do the washing up, you might respond: “are you saying I don’t support you around the house? That’s unfair.”

On the global stage, one of the big straw man arguments in recent times is the rhetoric of the anti-vaxxer, applied to resistance to mandated vaccines, social distancing, or lockdowns. The simplified term is a way of positioning someone as extreme, even if raising valid points, or looking to open dialogue about the repercussions of certain political choices, made without the option for the population to have their say.

5. Appeal to Authority

If someone in a position of authority says something is true, it must be true. This type of logical fallacy is ingrained in the psyche in childhood, where your parents' (or adults around you) word was final. Society is moving increasingly in this direction, especially in the fields of science. But that doesn’t come without risk, as even experts are known not to get things right.

In addition, many positions of authority aren’t always acting in pursuit of honesty or truth, if other factors (such as financial donations) have influence. While appeals to authority used to gravitate around religious leaders, a 2022 study found that, when linked with scientists, untrue statements are more likely to be believed, in what researchers call the Einstein effect .

6. False Dichotomy

Also known as the false dilemma, this logical fallacy presents limited options in certain scenarios in a way that is inaccurate. It’s closely linked to black-or-white thinking or all-or-nothing thinking, presenting two extremes without options in between. This is perhaps one of the most invasive logical fallacies in navigating life’s demands. For example, you either go to the gym or become unhealthy.

These limitations require a dose of psychological flexibility and creative thinking to overcome. They require exploring other alternatives. In the example above, that would mean looking at other ways to become healthy and exercise, such as running outdoors or going swimming.

7. Slippery Slope Fallacy

Similar to the straw man fallacy, the slippery slope is a way of taking an issue to a hypothetical extreme and then dismissing it based on what could happen. The potential of one thing leading to another, and the repercussions of that chain of events, may cause the original issue to be overlooked. For example, if you fail to set a boundary in one situation, you’ll forever be stuck in accepting certain behaviors.

The issue with this fallacy is that a valid process of critical thinking is to look at what decisions can lead to in the future. Rather than dismiss outright, however, it pays to make reasoned decisions, avoid jumping to conclusions, and see how things unfold over time.

8. Sunk Cost Fallacy

This is the logical fallacy that, when having already invested in something, you continue to invest in order to get return on your sunk costs. Although using gambling terminology (such as chasing losses on roulette) the sunk cost can apply to any area of life. The investment itself doesn’t have to be financial. For example, investing lots of time and energy into a creative project, or a relationship.

The sunk cost fallacy causes people to overlook a true and accurate analysis of the situation in the present moment, instead choosing to continue because of past decisions.

9. Hasty Generalisation

Also known as an over-generalization or faulty generalization, this logical fallacy makes general claims based on little evidence. Before writing this article, I went to a new gym, where my toiletry bag was stolen. You could argue it’s bad luck for something like that to happen on your first visit. If I decide that the gym isn’t safe, and make a hasty generalization, I may end up not going again. But what if the rate of theft in this gym was below the average in the city, and I was just unlucky? What if it wasn’t stolen, but someone absent-mindedly put it in their bag?

The opposite of a hasty generalization is to find the appropriate context for events. A logical conclusion, on the other hand, takes time. It’s reasonable, doesn’t jump in, and collects as much data as possible. If I go to the same gym, and something else is stolen, and I then see in Google reviews that others have had the same, it’d be logical for me to conclude there’s a high rate of theft.

How to Detect and Overcome Logical Fallacies

Both logic and critical thinking can be improved with practice. The knowledge of the nature of logical fallacies, and the above examples, will get you started. Deciphering when certain fallacies are active in real time is part of applied learning. Be conscious of applying the same level of rigor to your own level of reason as you do others.

There are a few components to detect and overcome logical fallacies. The first is self-awareness. As mentioned above, we’re humans, not machines. In situations where the stakes are high, we’re usually driven by factors other than logic, ulterior motives, or strong emotions that run the show. How often, when angry or triggered, do you say or act in ways you later regret?

Emotional regulation is useful in being calm enough to engage in critical thinking. But at times, logic isn’t the most skillful. For example, in conflict with a loved one, it’s more important to attempt to have compassion and understanding than to be the “most logical.” Sometimes, there are factors outside of reason that influence us, matters of the heart that can’t be captured, defined, or deconstructed by the mind.

Knowing how to apply logic, and when, is a vital skill. Through practice, over time, you’ll cultivate an even greater virtue — wisdom. A precious commodity in short supply, if you’re able to achieve wisdom and reason, the world is your oyster, a positive slippery slope to supercharge your growth.

KEEP READING

What is cognitive bias how to wave goodbye to mental distortions, hot stories, adopted woman finds her biological father in nursing home 56 years later — becomes his full-time caregiver, woman stops visiting her baby daughter in the hospital - so the married nurses taking care of her take her in, dan lok | my hero is my teacher, rude customer has a disagreement over $6 - teen employees have the perfect response, poor boy couldn’t afford to bury his mom - so he takes matters into his own hands, leonardo dicaprio told kate winslet to “let the fat girl thing go”, pamela anderson opens up about her 9 disastrous weddings.

Pamela Anderson has it all: beauty, fame and success. So why can’t the most famous blonde find her fairytale ending? Why is Pamela so unlucky in love and what dark secrets lie behind her seemingly glamorous life?

The Many Marriages of Pamela Anderson

See on Instagram

Pamela Anderson had a fairytale look at weddings from a young age. "I'd meet somebody, fall in love, and it would just be very romantic and it would be love at first sight."

But sadly, none of her nine weddings led to that dream relationship for the 56 year old actress.

While she looks to have found peace and calm in her later years, Anderson's previous relationships were fraught with abuse, drugs, and fear.

How many husbands did Pamela have over the years?

Pamela Anderson and Tommy Lee (1995-1998, 2008-2010)

The bad-boy of rock, Motley Crue drummer Tommy Lee, was the first man to sweep Anderson off her feet. The two stars had a whirlwind relationship that resulted in sons Brandon and Dylan. But what was once a fairytale marriage was also incredibly 'tragic,' ending in Tommy Lee being charged with spousal and child abuse.

While the Baywatch babe refers to Tommy Leed as "the only man I ever really loved was Tommy Lee," the two were not able to make it work.

Anderson and Kid Rock (2001-2003, 2006)

Anderson married the controversial rapper and musician a total of four times, though she knew it was a mistake, "right when I got married."

It looks like there was no love lost, as both have confirmed they never spoke again after the split.

Pamela Anderson and Rick Salomon (2007, 2013-2015)

Rick Salomon made a name for himself as a sometimes actor and poker player. Salomon turned out to have a serious drug addiction which Anderson only discovered when she found his crack pipe in the Christmas tree. Their marraige was annulled but they reconciled in 2013, thought the second marriage was short-lived.

Pamela Anderson and Jon Peters (2020) Kind of...

While it turned out the two never had an official marriage certificate, Anderson did announce her marraige to movie producer Jon Peters. Husband number five didn't last long, just a mere 12 days before the two split.

Pamela Anderson and Dan Hayhurst (2020-2022)

Anderson met her last husband, Dan Hayhurst, when he was the contractor for her house. The marriage survived two years before they went their separate ways.

"You know, it was more like trying to put a family unit back together. But I wasn't really in love. I just was going through the motions and then realizing, I have nothing in common with this person. Like I was putting people in my life to kind of numb some of the pain or be with someone, companionship, but nothing nothing healthy."

Woman “Accidentally” Forgets to End Call Before Speaking About Daughter-In-Law

Mother-in-Law Routinely Tricks Woman With This Phone Hack

Even though we’re told we shouldn’t care what other people think of us, deep down, many of us still do. Wanting to be accepted and loved is natural, and it can be devastating to hear someone talk badly about us behind our backs.

However, hearing someone say nice things about us when they don’t think we’re listening can be incredibly uplifting . One mother recognizes that, which is why she routinely "forgets" to hang up on her daughter-in-law.

A Secret Good Deed

A mother-in-law made sure to make her daughter-in-law feel special

Mother-in-law and daughter-in-law relationships can have a bad reputation. Many accounts of power struggles and differing points of view in the media and online set the tone for how some people expect these connections to be. But that’s not always the case, and this mother-in-law proves it.

Recently on Reddit, someone asked what secrets people are hiding that they would be willing to share online. A user named Kindly-Article-9357 had the best response: she was secretly uplifting her daughter-in-law.

“I've started to on occasion ‘accidentally’ (but on purpose) not hang up my phone correctly when getting off a call with my daughter-in-law,” she shared . “I then proceed to talk to my husband about how much I enjoy talking to her, how lovely I think she is, how glad I am that our son chose her, and whatever other boost I may think she needs.”

A Chosen Family

According to the woman, her daughter-in-law doesn’t have any family that uplifts her, and historically, that tears her down. So she decided to uplift the woman with these calls. It all started because she had accidentally butt-dialed her daughter-in-law one day and didn’t realize it when she began talking about her.

“I started doing this after my son told me about his wife coming to him in full-on snot tears,” she recalled of the experience. “She stayed on the line to hear what I ‘really’ thought of her, expecting the worst because that's been her experience of family. Apparently, she was quite touched by the things I said, and my son told me it gave her a confidence boost that lasted weeks.”

Now, the woman uses age to her advantage to continue making the couple feel good.

“So I do it more often now. Neither of them have any idea I do it on purpose, though. They just think I'm getting old and worse at managing my tech,” she added.

Leading By Example

According to the woman, she was inspired to foster a positive relationship with her son’s wife after her own experiences dating a man with a terminally ill mother.

“She had this calm serenity about her that I think only comes from making peace with your own death,” she added in the comments. “*She* treated me like her own daughter , and it made me feel so seen and accepted. It is her example that I try to follow with my own kids and their spouses.”

The story touched many in the comments, especially those who wished their own relationships with their in-laws were stronger and people who said they could use a boost like that themselves.

“As a girl who grew up feeling like a failure and a burden, this makes me cry. You're a wonderful MIL and the world needs more people like you,” one person shared.

Speaking With Kindness

It’s one thing to speak nicely about others when they’re listening, but it’s a whole other thing when someone overhears you speaking kindly about them. It’s validating and uplifting and something we can easily do for one another in life without much effort.

We don’t need to fake hang-ups to uplift others. Speaking kindly about family members, children, friends, or coworkers on the regular increases the chances they might overhear you. Not only that but it’s been scientifically proven that others may begin to see you as having the same positive traits that you’re talking up about someone else.

No one ever really knows what someone else is going through, and your words may one day be the boost a person needs. At the very least, you can feel good about yourself for doing your part to be kind and to make your corner of the world a warmer, safer place.

*Featured image contains photos by Karolina Kaboompics

Mom Asks Woman To Give Up Her First-Class Seat For Her Child - People Are Applauding Her Response

Desperate man needs to pay rent - decides to give his money to a stranger instead, grandma forced to sell homemade goods to get by - then, a stranger walks up to her, grieving daughter goes thrift store shopping - finds an unexpected note in a purse, why paul walker left his only daughter with vin diesel, matthew mcconaughey’s life-changing lesson for kate hudson (video), snoop dogg confronts the man that got tupac killed (video), jennifer hudson's horrific family tragedy-how the singer forgave and healed, subscribe to our newsletter, nicola coughlan has brilliant response to fan calling her bridgerton scenes "very brave", the untold story of michael and janet jackson's complex relationship, the disturbing and beautiful story behind danny trejo's salma hayek tattoo, the 11 best bridgerton quotes to make you feel powerful, romantic and wise, 40-year-old mom spent three years in prison - now she's an intern at princeton.

40-Year-Old Mother of 3 Goes From Inmate to Princeton Intern

Life can take us down unexpected and scary roads. Sometimes, we don’t know how to get off those roads and begin the climb to a better future. As this mom proved, however, anything is possible with a second chance and a little determination .

A Former Inmate

Woman goes from inmate to Princeton intern.

Mary McCrary is a 40-year-old mother of three who spent three years in prison. According to Good Morning America , she served time at the Debra K. Johnson Rehabilitation Center in Nashville for a parole violation following a conviction for aggravated burglary.

McCrary dropped out of high school in Grade 10 and has since successfully pursued her GED, but it wasn’t until prison that she began thinking about further education . She hit a breaking point behind bars and decided it was time to turn her life around.

“When you get to a point where you're tired and don’t even want to live and you're hopeless and you feel useless and worthless, you have a decision to make,” she told the publication.

“I made the decision to use this time to do something different, to change my life, because I didn’t want to keep doing the same things and getting in trouble and ... doing whatever I had to to survive because it gets you in the exact same place.”

So, McCrary enrolled in a coding class as part of the center’s Persevere program, an initiative aimed at helping inmates earn certifications as front-end or full-stack web developers.

“The class alone made you feel like you’re a human being, that I was working towards something, that there is a goal in sight, I am going to accomplish something, and I did,” she added. “That does give you confidence and hope.”

A Life-Changing Opportunity

For the next six months, McCrary earned her certificate in front-end coding. She decided to develop her skills even more by enrolling at Nashville State Community College, which offers a program for inmates.

This past May, McCrary was granted parole, completed her supervision, and earned extra credits toward an associate’s degree. But not even she could anticipate what would happen next: an internship at Princeton.

The nine-week program is meant for formerly incarcerated undergrad students to gain experience and new opportunities, and so far, McCrary is excelling.

“Her dedication to building her future is evident in how she does not shy away from challenges and the unknown,” Bridgett vonHoldt, an associate professor at Princeton and the head of the internship program said. “She is a role model, demonstrating for anyone who thinks such change is impossible that nothing is impossible.”

As for McCrary, she knows this is an incredible opportunity and hopes the internship is the next step toward earning her AA degree back in Nashville.

“This has been life-changing in more ways than one. This is an unbelievable, sometimes overwhelming experience,” she said. “If you look at my past, it's a crazy shamble mess, but look now, look what can happen. Nothing is ever impossible.”

Second Chances

McCrary hopes to be a role model for those who are having a hard time accepting the idea of a brighter future and so far, she certainly is. She’s a great example of how things can get better and you can change your future when you’re willing to take advantage of the opportunities you have — even if they don’t seem like opportunities at the time.

This story is also a needed reminder that everyone deserves a second chance in life and that sometimes, by allowing someone who has messed up the chance to try again, they may surprise you.

No one is perfect, and everyone stumbles. It’s not how hard we fall that truly matters in life; it's how we pick ourselves back up. But it’s also up to us whether we want to be the person who lends someone on the ground a helping hand or if we want to be the guy who just keeps on walking.

Get stories worth sharing delivered to your inbox

Everyday Psychology. Critical Thinking and Skepticism.

What are Logical Fallacies? | Critical Thinking Basics

Logical fallacies are errors in reasoning or flawed arguments that can mislead or deceive. They often appear plausible but lack sound evidence or valid reasoning, undermining the credibility of an argument. These errors can be categorized into various types, such as ad hominem attacks, strawman arguments, and false cause correlations.

Impact on Critical Thinking, Communication, and Social Interactions

The presence of logical fallacies hampers critical thinking by leading individuals away from rational and evidence-based conclusions. In communication, they can create confusion, weaken the persuasiveness of an argument, and hinder the exchange of ideas.

In social interactions, reliance on fallacious reasoning can strain relationships, impede collaboration, and contribute to misunderstandings.

Benefits of Identifying and Managing Logical Fallacies

Learning to identify logical fallacies enhances critical thinking skills, enabling individuals to analyze arguments more effectively and make informed decisions. In communication, recognizing fallacies empowers individuals to construct more compelling and convincing arguments, fostering clearer and more meaningful exchanges.

Moreover, the ability to manage logical fallacies promotes healthier social interactions by minimizing misunderstandings, encouraging constructive dialogue, and fostering a more intellectually robust and collaborative environment.

RETURN TO THE MAIN RESOURCE PAGE: CRITICAL THINKING BASICS

Module Four: Delivery of Demonstration Speeches

Critical thinking & reasoning: understanding fallacies.

When we form arguments or examine others’ arguments, we need to be cognizant of possible fallacies. A fallacy can be defined as a flaw or error in reasoning. At its most basic, a logical fallacy refers to a defect in the reasoning of an argument that causes the conclusion(s) to be invalid, unsound, or weak. The existence of a fallacy in a deductive argument makes the entire argument invalid. The existence of a fallacy in an inductive argument weakens the argument but does not invalidate it.

It is important to study fallacies so you can avoid them in the arguments you make. Studying fallacies also provides you with a foundation for evaluating and critiquing other arguments as well. Once you start studying and thinking about fallacies, you’ll find they are everywhere. You could say that we live in a fallacious world!

The study of fallacies can be dated back to the start of the study of logic. In ancient Greece, Aristotle classified fallacies into two categories—linguistic and non-linguistic. Within these two categories, he identified 13 individual fallacies. Through time we have reclassified fallacies using various typologies and criteria. For our purposes, we will focus on formal and informal fallacies.

“Exclamation in a circle” by Orikrin1998. CC-BY .

Chapter 6 Understanding Fallacies. Authored by : Terri Russ, J.D., Ph.D.. Provided by : Saint Mary's College, Notre Dame, IN. Located at : http://publicspeakingproject.org/psvirtualtext.html . Project : The Public Speaking Project. License : CC BY-NC-ND: Attribution-NonCommercial-NoDerivatives
Exclamation in a circle IS. Authored by : Orikrin1998. Located at : http://commons.wikimedia.org/wiki/File:Exclamation_in_a_circle_IS.svg . License : CC BY: Attribution

Jessie Ball duPont Library

Critical thinking skills, watch the fallacies.

Need Research Help?
Research Help

Although there are more than two dozen types and subtypes of logical fallacies, these are the most common forms that you may encounter in writing, argument, and daily life:

Example: Special education students should not be required to take standardized tests because such tests are meant for nonspecial education students.

Example: Two out of three patients who were given green tea before bedtime reported sleeping more soundly. Therefore, green tea may be used to treat insomnia.

Sweeping generalizations are related to the problem of hasty generalizations. In the former, though, the error consists in assuming that a particular conclusion drawn from a particular situation and context applies to all situations and contexts. For example, if I research a particular problem at a private performing arts high school in a rural community, I need to be careful not to assume that my findings will be generalizable to all high schools, including public high schools in an inner city setting.

Example: Professor Berger has published numerous articles in immunology. Therefore, she is an expert in complementary medicine.

Example: Drop-out rates increased the year after NCLB was passed. Therefore, NCLB is causing kids to drop out.

Example: Japanese carmakers must implement green production practices, or Japan‘s carbon footprint will hit crisis proportions by 2025.

In addition to claims of policy, false dilemma seems to be common in claims of value. For example, claims about abortion‘s morality (or immorality) presuppose an either-or about when "life" begins. Our earlier example about sustainability (―Unsustainable business practices are unethical.‖) similarly presupposes an either/or: business practices are either ethical or they are not, it claims, whereas a moral continuum is likelier to exist.

Begging the Question/Circular Reasoning

Hasty Generalization

Sweeping Generalization

Non Sequitur

Post Hoc Ergo Propter Hoc

False Dilemma

<< Previous: Abduction
Next: Need Research Help? >>
Last Updated: Aug 15, 2024 6:00 PM
URL: https://library.sewanee.edu/critical_thinking

Research Tools

Find Articles
Find Research Guides
Find Databases
Ask a Librarian
Learn Research Skills
How-To Videos
Borrow from Another Library (Sewanee ILL)
Find Audio and Video
Find Reserves
Access Electronic Resources

Services for...

College Students
The School of Theology
The School of Letters
Community Members

Spaces & Places

Center for Leadership
Center for Speaking and Listening
Center for Teaching
Floor Maps & Locations
Ralston Listening Library
Study Spaces
Tech Help Desk
Writing Center

About the Library

Where is the Library?
News and Reports
Library Collections
New Items & Themed Collections
Library Policies
Library Staff
Friends of the Library

Jessie Ball duPont Library, University of the South

178 Georgia Avenue, Sewanee, TN 37383

931.598.1664

Pursuing Truth: A Guide to Critical Thinking

Chapter 9 informal fallacies.

A fallacy is a mistake in reasoning. A formal fallacy is a fallacy that can be identified merely by examining the argument’s form or using a tool like a truth table. An informal fallacy cannot be detected from the argument’s form. There are no foolproof tools for detecting informal fallacies. Unlike validity, these fallacies can occur in degrees. Sometimes, it is clear that a fallacy has been committed, at other times, there can be legitimate questions about whether a fallacy has been committed.

9.1 Emotions and Critical Thinking

There are two important uses of language that play an important role in critical thinking. The first is to convey information, or what is sometimes called cognitive content. The premises and the conclusion of an argument all have cognitive content. It is on the basis of the information they convey that we can evaluate them as true or false. Another use of language, however, is to express emotion, which often tends to evoke similar feelings in the audience. The emotions that are expressed by the language is its emotive content.

Good critical thinkers are persuaded by relevant cognitive content, and are not unduly persuaded by irrelevant emotive content.

9.2 Slanters

Slanters are words or phrases that are used to manipulate by using emotive language. Slanters can have both positive and negative connotations. Slanters are types of non-argumentative persuasion. Sometimes, people will use them innocently, maybe because they have passionate feelings about the subject being discussed. Other time, though, they are used because the speaker knows that he does not have a good argument for his position. They are ways for people to affect the beliefs of others without offering reasons for their positions.

9.2.1 Euphemisms and Dysphemisms

Different words and phrases passages can have the same cognitive content but differ in their emotive content. A euphemism is a positive synonym for some neutral term. A dysphemism is a negative synonym. For example, think of the words that we use to talk about the death of a pet:

Neutral: euthanize
Euphemism: put to sleep
Dysphemism: ?

Euphemisms are common in the military and in advertising. Here are some examples:

Enhanced interrogation methods
Collateral damage
Depopulated area
Pre-owned, Pre-loved
Genuine imitation leather

In other cases, a person may use a euphemism when they have been caught doing something wrong, but want to minimize the wrongness of the action. I heard a politician once, who was caught telling a falsehood, admit to having “committed terminological inexactitude.”

Dysphemisms convey a negative attitude towards something. Examples of dysphemisms include:

Cancer stick
Dead tree edition

9.2.2 Innuendoes

Innuendoes imply something by what is not said. A common scene in crime films has a gangster go into a store and say something like “Nice store you got. It would be a shame if anything happened to it.” Notice that he didn’t actually say he would damage the store, although he certainly implied it.

Another use of an innuendo is to condemn with faint praise. Imagine receiving a reference letter for a student applying to graduate school. The letter only says that the student was never late to class. The implication is that her punctuality is the best that can be said of her.

Finally, there is the apophasis, which is mentioning something by saying that it won’t be mentioned. For example, “I’m not going to talk about your failure to turn assignments in on time.”

9.2.3 Weaselers

A weaseler is a way of qualifying a claim in order to avoid criticism. Weaselers include words and phrases like “perhaps,” “there’s a good chance that,” and “it’s possible that.” A weaseler that is common in advertising is “up to” — “By using our diet plan, you can lose up to ten pounds in a month.” Notice that “up to ten pounds” means “no more than ten pounds.” So, if a customer loses no weight at all, then there is no grounds for a lawsuit.

9.2.4 Downplayers

A downplayer is a way of making something seem less important than it is. The most common downplayers are “mere, merely, and so-called.” A person might say, “That’s merely your opinion” to avoid having to respond with facts. A politician might talk about his opponent’s “so-called” plan to cut spending, implying that it isn’t much of a plan at all. Improper use of quotation marks can also serve as a downplayer.

9.2.5 Proof surrogate

A proof surrogate offers no real support, but just claims that support exists. Examples are using “studies show” without saying what those studies are and where they can be found. Another proof surrogate is just to say that “It’s obvious that….” Doing so implies that proof is simply not needed.

9.2.6 Hyperbole

Hyperbole is an inappropriate or extreme exaggeration. “Taking critical thinking is the most exciting thing you’ll do in your whole life!” Since it is an extreme exaggeration, no one will be fooled into believing it, so what’s the danger? The danger of hyperbole is that once the exaggeration is made, the listener is then prepared to accept a weaker version of the statement. The weaker version, compared to the extreme exaggeration, sounds more believable.

9.3 Fallacies of Ambiguity and Vagueness

An ambiguous word or phrase is one that has more than one meaning. “Bank” is an ambiguous term, it can refer to a financial institution, a riverbank, a kind of basketball or pool shot, etc. A vague term is one that does not have a precise meaning. That is, there will be cases where a vague term clearly applies, cases in which it clearly does not apply, and cases in the middle where it’s just not clear whether it applies. Terms like “rich” and “heap” are vague terms.

9.3.1 Equivocation

The fallacy of equivocation is committed by using the same term in two different senses in the same argument. Here is my favorite example:

God is love.
Love is blind
Ray Charles is blind.
Ray Charles is God.

There are several things wrong with this argument, one of them is equivocating on “blind.” To say that love is blind, is to say that people overlooks the faults of those they love. To say that Ray Charles is blind is to say that he cannot physically see anything, not that he just overlooks things.

9.3.2 Amphiboly

Amphibolies rely on syntactic ambiguities. Those are ambiguities that result from the arrangement of the words. Church bulletin bloopers are good places to find amphibolies: “The Rev. Adams spoke briefly, much to the delight of his audience.”

9.3.3 Accent

The fallacy of accent is an equivocation resulting from accenting different words in a sentence. Think about the different meanings that are implied from accenting different words in this sentence: “I didn’t take the exam yesterday.”

9.3.4 Division and Composition

The last two fallacies of ambiguity are division and composition. The fallacy of division improperly attributes a property of the whole to its parts. The fallacy of division improperly attributes a property of the parts to the whole. Here is an example of division: “That wall weighs more than 500 pounds, so each brick in it weighs more than 500 pounds.” A similar example of composition is “Each brick in that wall weighs less than a pound, so the entire wall weighs less than a pound.”

Some properties, however, can be attributed from the parts to the whole or the whole to the parts. For example, “Each link in that chain is solid gold, so the whole chain is solid gold.”

9.3.5 Line-Drawing Fallacy

The line-drawing fallacy is a fallacy of vagueness, having the form “Since there is no precise line that can be drawnd between A and not-A, there is no real difference between A and not-A.” Example: “Since no one can say where the line should be drawn between legitimate uses of force and excessive uses of force, then no one can honestly claim that any use of force is excessive.”

9.4 Fallacies of Relevance

A good critical thinker will offer arguments that have premises that are logically relevant to their conclusions. A fallacy of relevance is committed when the premises of the argument are not logically relevant to the truth of the conclusion. They may be, however, psychologically relevant, so that we can be deceived in thinking that the argument is valid, when in fact it is not.

9.4.1 Ad Hominem

The Ad Hominem fallacy is committed by attacking the person giving the argument, rather than responding to the argument itself. There are four common types:

9.4.1.1 Personal Attack

This is also known as an ad hominem abusive. This is committed when one verbally attacks the person giving the argument instead of responding to the argument itself. For example:

Jack: “There are so many unexplored planets out there. Surely, there must be life somewhere out there”

Jill: “You can’t be right, you’re just a loser who watches too much television.”

9.4.1.2 Circumstantial Ad Hominem

A person commits the circumstantial ad hominem by referring to circumstances that discredit the arguer. This is often a charge of bias or vested interest. A person has a vested interest when they stand to gain, financially or otherwise, by something. For example, a doctor has a vested interest in a pharmaceutical study when she owns stock in the company that produces the drug. Bias or vested interest is a good reason to examine an argument carefully, but not a good reason to simply dismiss it.

Jill: John has made an excellent case for increasing the budget of the church’s youth program.

Jack: Of course he would say that — he’s the youth minister! You can just forget everything he said.

9.4.1.3 Tu Quoque

This is also known as a pseudorefutation. It accuses the arguer of hypocrisy. Example: “Don’t tell me I shouldn’t start smoking. I know how many packs a day you inhale!”

A person’s behavior may very well be inconsistent with their argument, but that doesn’t mean that the argument is bad.

9.4.1.4 Poisoning the Well

Poisoning the well is an ad hominem committed before the arguer has spoken. The goal is to provide harmful information about the speaker to preemptively discredit anything that the speaker might say. Any of the previous examples can be turned into examples of poisoning the well. For example: “John is about make his case for increasing the church’s youth budget. Don’t pay any attention to him — he’s the youth minister, what else would he say?”

9.4.2 Appeal to Force

The appeal to force, also called scare tactics, is a threat, either explicit or implicit. For example, imagine a student saying to a professor, “I deserve an A because my father is a major donor to this university and a very good friend of the dean.” The appeal to force tries to instill fear in the listener, and to be fallacious, the fear must be irrelevant to the truth of the claim. These are common in both advertising and politics. An example of an appeal to force in advertising would be an ad for a Medicare supplement policy with an elderly woman weeping in front of a pile of unpaid bills. The advertisement works by making the viewer afraid of ending up like the person in the commercial.

9.4.3 Appeal to Pity

The appeal to pity is like the appeal to force, except that the goal is to evoke pity, not fear. For example: “I deserve an A because my mother is very ill, and I had to spend most of my time caring for her this semester.”

9.4.4 Popular Appeal

This is also called appeal to the people. Here, the goal is to use the desire to be loved, admired, accepted, etc. to get others to accept the conclusion. Two important types are the bandwagon fallacy and the appeal to vanity.

9.4.4.1 Bandwagon

The bandwagon fallacy tells the listener that since everyone does, or believes, something, then they should too.

Example: “Everyone supports Smith for president. You need to get with the program and support him too!”

9.4.4.2 Appeal to Vanity

This is a claim that you will be admired if you do this. Unlike bandwagon, which claims that everyone does this, the appeal to vanity is usually about something that not everyone can do or have.

Example: “Wear a Rolex — that way everyone will know that you’re not just somebody.”

9.4.5 Appeal to Ignorance

9.4.5.1 burden of proof.

On most issues, one side will have the burden of proof. That means that if that side fails to make its case, then the other side wins by default. There are two standard rules for determining burden of proof:

Especially for existence claims, the side making the positive case has the burden of proof.
The side making the more implausible claim has the burden of proof.

Sometimes, these conditions can conflict. Here is an example:

Jill: Surely, there are species of insects that we have not yet discovered.

Jack: I don’t think that’s true.

Who has the burden of proof? Jill is making a positive existence claim, but it is one that very plausible. That makes Jack’s claim very implausible. In this case, I’d say that Jack has the burden of proof.

9.4.5.2 The Law

One area where these rules do not apply is the American legal system. There, the prosecution always has the burden of proof. That is, if the prosecution fails to make its case against the defendant, then the defense wins.

Burden of proof should not be confused with standard of proof. Burden of proof is concerned with who needs to make their case. Standard of proof is concerned with how strong a case needs to be made. There are four different levels of standard of proof in the law:

Beyond a reasonable doubt
Clear and convincing evidence
Preponderance of evidence
Probable cause

Criminal cases use the highest standard of proof, which is “beyond a reasonable doubt.” This is a high degree of probability. It does not mean that no doubt at all is possible, but that any doubt, given the evidence, would be unreasonable. The next two level are used in civil cases. Most civil cases are tried at the “preponderance of evidence” level. This means that, given the evidence, it is more likely that the defendant is liable than not. Clear and convincing evidence is a standard of proof between preponderance of evidence and beyond a reasonable doubt. It is used in civil cases that involve the potential loss of important rights or interests, such as the termination of potential rights. The lowest standard of proof is probable cause. This is used to determine if a search or arrest is warranted, and also used by grand juries to issue indictments.

9.4.6 Straw Man

The straw man fallacy Distorts a position so that it can be easily attacked. It does not address the actual view held by the opponent, but responds to a weaker version. It is often committed by making the conclusion of an argument more extreme than it actually is, since extreme views are often easy to attack.

Example: “Senator Snodgrass has argued that there be a mandatory waiting period before any handgun purchase. Obviously, the senator wants to make all firearm ownership illegal.”

Here some subtle ways of committing the fallacy:

Taking words out of context.
Treating extreme views as representative.
Criticizing early versions of a position.
Criticizing deliberately simplified versions of a position.

9.4.7 Red Herring

The goal of the red herring fallacy is to lead the opponent off the track, by subtly changing the issue being discussed. The arguer changes the subject to a different but related one. To determine if something is a red herring, ask yourself if the issue at the beginning of the argument is the same as the issue at the end. Here is an example:

The American Cancer Society has argued that smoking is bad for your health. Many people in the Southeastern United States are dependent upon the tobacco industry for their jobs. Making smoking illegal would have a devastating economic effect on many states. Therefore, the ACS is simply wrong.

Notice the original isse is whether smoking has bad health consequences. By the end of the paragraph, the issue has been changed to the economic impact of making smoking illegal.

9.4.8 Horse Laugh

This occurs when someone simply ridicules the position held, and offers no real response to the argument at all. For example: “Mr. Jones has argued that watching television is emotionally unhealthy. If you believe that, then I’ve got a great deal on some swampland for you.”

9.5 Fallacies of Unwarranted Assumptions

9.5.1 begging the question.

An argument begs the question if it is impossible to believe at least one of the premises unless one already believes the conclusion. Note that if this is the case, then the premises cannot serve as reasons to believe the conclusion, since believing the premises requires already believing the conclusion. There are three common types of arguments that beg the question.

The first is a circular argument. That occurs when one explicitly uses the conclusion as support for one of the premises. Here is an example:

The Bible says that God exists.
The Bible is the inspired word of God.
God exists.

The Bible can’t be the inspired word of God unless God exists, so the argument begs the question.

Another type of argument that begs the question is one that simply rephrases the conclusion and uses it as a premise. Example: “If such actions were not illegal, then they would not be prohibited by the law.” In this case, the conclusion is synonymous with one of the premises.

The last type is one that generalizes the conclusion and uses the generalized rule as a premise. Example: “Spanking children is wrong because corporal punishment is wrong.”

9.5.2 Appeal to Authority

The fallacy of appeal to authority is committed by using an pseudo-authority to support a claim. Note that it is not committed by merely appealing to an authority, but by appealing to an unqualified authority. Always ask, “Should this person know more about this subject than the average person?”

9.5.3 Loaded Question

A loaded question suggests something with the question. “Whem will you stop cheating on exams?” is a loaded question, the question implies that the person is cheating. Notice that there is no way to directly answer the question without admitting to cheating on exams.

9.5.4 False Dilemma

This is sometimes called the either-or fallacy. This happens when a person asserts a disjunction, a sentence of the form "either A or B , when there is at least one more option that is true. Disjunctions are true whenever at least one of the disjuncts, the sentences joined by the ‘or,’ are true. A False dilemma asserts that one of the two sentences must be true when there is really a third alternative. Here are some examples:

“Either buy our personal financial guide or never have control of your finances.”

Child to parent: “Either let me go to the party or I’ll just die.”

False dilemmas are often expressed in pithy slogans on bumper stickers: “It’s my way or the highway” or “America, love it or leave it.”

Consider this example: “My opponent voted against the public schools spending bill. He must think educating our children is not important.” The claim is that either one votes for the bill or one believes that education is not important. This is a false dilemma since there may be many other reasons to vote against a particular bill.

It’s important to remember that a disjunction can be expressed as a conditional: “Either let me go to that party or I’ll die” is equivalent to “If you don’t let me go to that party, then I’ll die.” In general, P or Q is equivalent to if not-P then Q.

9.5.5 Slippery Slope

Slippery slopes rest a conclusion on a chain reaction that is not likely to occur. They generally have this form:

In order for this to be a fallacy, at least one of the conditional statements in the premises must not be likely to be true. Here’s an example: “If I fail this test, then I will fail the course. If I fail the course, then I’ll be expelled from school. If I’m expelled from school, then I’ll never be able to have a good job. If I can’t get a good job, then I can’t support a family…”

To test for a slippery slope, just ask, are there any weak links in this chain of conditionals? Is it really the case that one failed exam will result in an F for a course grade?

Purdue Online Writing Lab Purdue OWL® College of Liberal Arts

Logical Fallacies

Welcome to the Purdue OWL

This page is brought to you by the OWL at Purdue University. When printing this page, you must include the entire legal notice.

Copyright ©1995-2018 by The Writing Lab & The OWL at Purdue and Purdue University. All rights reserved. This material may not be published, reproduced, broadcast, rewritten, or redistributed without permission. Use of this site constitutes acceptance of our terms and conditions of fair use.

Fallacies are common errors in reasoning that will undermine the logic of your argument. Fallacies can be either illegitimate arguments or irrelevant points, and are often identified because they lack evidence that supports their claim. Avoid these common fallacies in your own arguments and watch for them in the arguments of others.

Slippery Slope: This is a conclusion based on the premise that if A happens, then eventually through a series of small steps, through B, C,..., X, Y, Z will happen, too, basically equating A and Z. So, if we don't want Z to occur, A must not be allowed to occur either. Example:

If we ban Hummers because they are bad for the environment eventually the government will ban all cars, so we should not ban Hummers.

In this example, the author is equating banning Hummers with banning all cars, which is not the same thing.

Hasty Generalization: This is a conclusion based on insufficient or biased evidence. In other words, you are rushing to a conclusion before you have all the relevant facts. Example:

Even though it's only the first day, I can tell this is going to be a boring course.

In this example, the author is basing his evaluation of the entire course on only the first day, which is notoriously boring and full of housekeeping tasks for most courses. To make a fair and reasonable evaluation the author must attend not one but several classes, and possibly even examine the textbook, talk to the professor, or talk to others who have previously finished the course in order to have sufficient evidence to base a conclusion on.

Post hoc ergo propter hoc: This is a conclusion that assumes that if 'A' occurred after 'B' then 'B' must have caused 'A.' Example:

I drank bottled water and now I am sick, so the water must have made me sick.

In this example, the author assumes that if one event chronologically follows another the first event must have caused the second. But the illness could have been caused by the burrito the night before, a flu bug that had been working on the body for days, or a chemical spill across campus. There is no reason, without more evidence, to assume the water caused the person to be sick.

Genetic Fallacy: This conclusion is based on an argument that the origins of a person, idea, institute, or theory determine its character, nature, or worth. Example:

The Volkswagen Beetle is an evil car because it was originally designed by Hitler's army.

In this example the author is equating the character of a car with the character of the people who built the car. However, the two are not inherently related.

Begging the Claim: The conclusion that the writer should prove is validated within the claim. Example:

Filthy and polluting coal should be banned.

Arguing that coal pollutes the earth and thus should be banned would be logical. But the very conclusion that should be proved, that coal causes enough pollution to warrant banning its use, is already assumed in the claim by referring to it as "filthy and polluting."

Circular Argument: This restates the argument rather than actually proving it. Example:

George Bush is a good communicator because he speaks effectively.

In this example, the conclusion that Bush is a "good communicator" and the evidence used to prove it "he speaks effectively" are basically the same idea. Specific evidence such as using everyday language, breaking down complex problems, or illustrating his points with humorous stories would be needed to prove either half of the sentence.

Either/or: This is a conclusion that oversimplifies the argument by reducing it to only two sides or choices. Example:

We can either stop using cars or destroy the earth.

In this example, the two choices are presented as the only options, yet the author ignores a range of choices in between such as developing cleaner technology, car-sharing systems for necessities and emergencies, or better community planning to discourage daily driving.

Ad hominem: This is an attack on the character of a person rather than his or her opinions or arguments. Example:

Green Peace's strategies aren't effective because they are all dirty, lazy hippies.

In this example, the author doesn't even name particular strategies Green Peace has suggested, much less evaluate those strategies on their merits. Instead, the author attacks the characters of the individuals in the group.

Ad populum/Bandwagon Appeal: This is an appeal that presents what most people, or a group of people think, in order to persuade one to think the same way. Getting on the bandwagon is one such instance of an ad populum appeal.

If you were a true American you would support the rights of people to choose whatever vehicle they want.

In this example, the author equates being a "true American," a concept that people want to be associated with, particularly in a time of war, with allowing people to buy any vehicle they want even though there is no inherent connection between the two.

Red Herring: This is a diversionary tactic that avoids the key issues, often by avoiding opposing arguments rather than addressing them. Example:

The level of mercury in seafood may be unsafe, but what will fishers do to support their families?

In this example, the author switches the discussion away from the safety of the food and talks instead about an economic issue, the livelihood of those catching fish. While one issue may affect the other it does not mean we should ignore possible safety issues because of possible economic consequences to a few individuals.

Straw Man: This move oversimplifies an opponent's viewpoint and then attacks that hollow argument.

People who don't support the proposed state minimum wage increase hate the poor.

In this example, the author attributes the worst possible motive to an opponent's position. In reality, however, the opposition probably has more complex and sympathetic arguments to support their point. By not addressing those arguments, the author is not treating the opposition with respect or refuting their position.

Moral Equivalence: This fallacy compares minor misdeeds with major atrocities, suggesting that both are equally immoral.

That parking attendant who gave me a ticket is as bad as Hitler.

In this example, the author is comparing the relatively harmless actions of a person doing their job with the horrific actions of Hitler. This comparison is unfair and inaccurate.

More From Forbes

Don’t be duped—know these 8 logical fallacies to boost your critical thinking.

Share to Facebook
Share to Twitter
Share to Linkedin

Having a solid foundation in logic can enable you to make decisions more carefully, to pause and ... [+] think through issues.

How often do you make assumptions?

Have a strong position that you can’t exactly back with facts?

Hear someone else’s strong position that sounds like nonsense?

Welcome to the world of logical fallacies.

They’re all around us, daily, monthly, hourly in our conversations with others. Leaders must be aware of these to be more effective. And politicians are the worst offenders—they love love love logical fallacies.

Logical fallacies are quite similar to cognitive biases which can be defined as the systematic departure from rational thinking . Logical fallacies compromise our ability to think critically and have sound logic to back up our position. They’re flaws in our logic.

How We Fool Ourselves And Others

Without solid logic we cannot create a persuasive argument. And having a solid foundation in logic can enable one to make decisions more carefully, to pause and think through issues. So why are logical fallacies—the departure from logic and facts to back up one’s argument—so prevalent today?

Best High-Yield Savings Accounts Of 2024

Best 5% interest savings accounts of 2024.

1. People can be lazy

2. It’s a quick seemingly effective strategy when under pressure and you need a ‘sleight of mouth’ like a magician’s sleight of hand

Once you know the most common logical fallacies, you’ll start to notice them constantly. Both in your, and others’, communication.

Before we dive into them, let’s see what’s happening in your brain when logical fallacies are used. If you don’t have an appropriate response or feel wobbly in your position, it’s likely your dorsal lateral prefrontal cortex is attempting to control your behavior so you come across as more credible. But that’s likely not going to work, since your amygdala is perceiving threat and thus attacking instead of simply dealing with the issue at hand. Your survival instinct will always win when your brain perceives threat!

The 8 Most Common Logical Fallacies

Which of these do you see most often in others? In yourself?

1. Ad hominim – attacking the person (not the issue) in order to divert attention to another topic and not deal with the original one.

a. Example: “You can’t have an opinion on climate change since you don’t recycle.”

b. Solution: bring the speaker back to the topic at hand

2. Red herring – distracting or misleading someone to prolong an argument or change the topic

a. Example: “Would you pick up the dry cleaning on the way home?” Reply: “You never take the trash out!”

3. Strawman – exaggerate a claim/topic to knock it down (see our blog on why people lie —you’ll find some helpful info there)

a. Example: “We need to figure out how to afford to best do business in California”. Reply: “Why are you telling us to shut down California operations?”

b. Solution: Ask yourself: Can two things be true at once? Do I know enough about the issue to even voice my opinion? Can I acknowledge that this is a complex multi-faceted topic?

4. Slippery slope – a claim that follows a progression and ultimately leads to disaster.

a. Example: “If we let animals into our store, then everyone will bring them and they’ll pee and poop all over the place and break the merchandise and scare the other shoppers away and we’ll go out of biz and have to file bankruptcy and move to the slums.”

b. Solution: There may be some logic here, and yes, there could be a domino effect, but one step does not always lead to another and ultimate disaster. Let’s consider all the possibilities and options.

5. False dilemma – a person claims there are only 2 options, ignoring all other options.

a. Example: – “If we don’t order dinner via Door Dash we’ll have to eat whatever is in the pantry and that’ll be awful.”

b. Solution: There are a TON of food sources besides Door Dash. Recognize that other options exist.

6. Hasty generalization – someone jumps to a conclusion or generalizes without thinking through or doing the research.

a. Example: “People who point their finger are rude.”

b. Solution: Really? ALL people who point are rude? Slow down, pause, think it through

7. Appeal to authority – exaggerate a person’s authority or expertise, and generally become close-minded.

a. Example: “My doctor said that if you want to be healthy you must stop drinking coffee.”

b. Solution: Consider more sources! Question authority!

8. Begging the question – a statement is made as fact without evidence that the claim is true

a. Example: “Acai is good for you because it’s a dark berry.”

b. Solution: Why are dark berries good for you? Where’s the evidence for this claim? Ask for the factual back up for the claim.

Notice when you and others use these logical fallacies. You’ll find that they’ll result in you no longer being offended when someone uses ad hominim against you, and you’ll also find that you’ll likely say “but why/that’s not the question I asked/where’s the proof” and other phrases to help others pause and assess their own logical fallacies.

Let’s all become more logical and stronger critical thinkers!

Editorial Standards
Reprints & Permissions

Join The Conversation

One Community. Many Voices. Create a free account to share your thoughts.

Forbes Community Guidelines

Our community is about connecting people through open and thoughtful conversations. We want our readers to share their views and exchange ideas and facts in a safe space.

In order to do so, please follow the posting rules in our site's Terms of Service. We've summarized some of those key rules below. Simply put, keep it civil.

Your post will be rejected if we notice that it seems to contain:

False or intentionally out-of-context or misleading information
Insults, profanity, incoherent, obscene or inflammatory language or threats of any kind
Attacks on the identity of other commenters or the article's author
Content that otherwise violates our site's terms.

User accounts will be blocked if we notice or believe that users are engaged in:

Continuous attempts to re-post comments that have been previously moderated/rejected
Racist, sexist, homophobic or other discriminatory comments
Attempts or tactics that put the site security at risk
Actions that otherwise violate our site's terms.

So, how can you be a power user?

Stay on topic and share your insights
Feel free to be clear and thoughtful to get your point across
‘Like’ or ‘Dislike’ to show your point of view.
Protect your community.
Use the report tool to alert us when someone breaks the rules.

Thanks for reading our community guidelines. Please read the full list of posting rules found in our site's Terms of Service.

Fallacies Card 12+

Indigo software solutions company limited.

Unlock the power of critical thinking with Fallacy Cards, the essential app for understanding and handling logical fallacies and cognitive biases. Perfect for students, professionals, and critical thinking enthusiasts, our app features concise, informative cards with clear definitions and real-world examples.

バージョン 1.2.1

デベロッパである" INDIGO SOFTWARE SOLUTIONS COMPANY LIMITED "は、アプリのプライバシー慣行に、以下のデータの取り扱いが含まれる可能性があることを示しました。詳しくは、デベロッパプライバシーポリシーを参照してください。

ユーザのトラッキングに使用されるデータ

次のデータは、他社のアプリやWebサイト間でユーザをトラッキングする目的で使用される場合があります。

ユーザに関連付けられたデータ

次のデータは収集され、ユーザの識別情報に関連付けられる場合があります。

プライバシー慣行は、ご利用の機能やお客様の年齢などに応じて異なる場合があります。詳しい情報

デベロッパWebサイト

Religion Encyclopedia

ThinkBetter: Critical Thinking

Russian 4K Language Quiz

BehavioralPedia

REBT Guide to Emotions

Mental.events

IMAGES

Fallacies in critical thinking
FALLACIES Critical Thinking First PPT July 2016
Logical Fallacies (A3 Worksheet / Poster)
😀 Types of fallacies in critical thinking. Importance of fallacies in
Fallacies and Bias
Pin on The More You Know

VIDEO

Fallacies by Family
Logical Fallacies Part (1)
Critical Thinking -- Fallacies
Critical Thinking: Quiz 2 discussion
logical Fallacies Part 2
Chronological Snobbery Fallacy

COMMENTS

Critical Thinking and Decision-Making: Logical Fallacies
Most logical fallacies can be spotted by thinking critically. Make sure to ask questions: Is logic at work here or is it simply rhetoric? Does their "proof" actually lead to the conclusion they're proposing? By applying critical thinking, you'll be able to detect logical fallacies in the world around you and prevent yourself from using them as ...
PDF The Thinker's Guide To Fallacies
The Foundation for Critical Thinking. To understand the human mind, understand self-deception. Anon. The word 'fallacy' derives from two Latin words, fallax ("deceptive") and fallere ("to deceive"). This is an important concept in human life because much human thinking deceives itself while deceiving others. The human mind has no ...
Fallacies
This is why we would like to define fallacies more broadly as violations of the principles of critical thinking, whether or not the mistakes take the form of an argument. The study of fallacies is an application of the principles of critical thinking. Being familiar with typical fallacies can help us avoid them and help explain other people's ...
LOGOS: Critical Thinking, Arguments, and Fallacies
LOGOS: Critical Thinking, Arguments, and Fallacies Heather Wilburn, Ph.D. Critical Thinking: With respect to critical thinking, it seems that everyone uses this phrase. Yet, there is a fear that this is becoming a buzz-word (i.e. a word or phrase you use because it's popular or enticing in some way). Ultimately, this means that we may be ...
Logical Fallacies: A Master List Of 100+ Examples
A Complete Logical Fallacies List With Examples For Critical Thinking. contributed by Owen M. Wilson, University of Texas El Paso. A logical fallacy is an irrational argument made through faulty reasoning common enough to be named for the nature of its respective logical failure. The A Priori Argument. Also: Rationalization; Dogmatism, Proof ...
Logical Fallacies
People sometimes confuse cognitive bias and logical fallacies because they both relate to flawed thinking. However, they are not the same: Cognitive bias is the tendency to make decisions or take action in an illogical way because of our values, memory, socialization, and other personal attributes. In other words, it refers to a fixed pattern of thinking rooted in the way our brain works.
Fallacies
Another consideration about the value of the fallacies approach to teaching good reasoning is that it tends to make students overly critical and lead them to see fallacies where there are not any; hence, it is maintained we could better advance the instilling of critical thinking skills by teaching the positive criteria of good reasoning and ...
9 Logical Fallacies That You Need to Know To Master Critical Thinking
The issue with this fallacy is that a valid process of critical thinking is to look at what decisions can lead to in the future. Rather than dismiss outright, however, it pays to make reasoned decisions, avoid jumping to conclusions, and see how things unfold over time. 8. Sunk Cost Fallacy.
What are Logical Fallacies?
Logical fallacies are errors in reasoning or flawed arguments that can mislead or deceive. They often appear plausible but lack sound evidence or valid reasoning, undermining the credibility of an argument. These errors can be categorized into various types, such as ad hominem attacks, strawman arguments, and false cause correlations. Impact on Critical Thinking,
Critical Thinking & Reasoning: Understanding Fallacies
At its most basic, a logical fallacy refers to a defect in the reasoning of an argument that causes the conclusion (s) to be invalid, unsound, or weak. The existence of a fallacy in a deductive argument makes the entire argument invalid. The existence of a fallacy in an inductive argument weakens the argument but does not invalidate it.
3.3: Fallacies
The study of fallacies is an application of the principles of critical thinking. Being familiar with typical fallacies can help us avoid them. We would also be in a position to explain other people's mistakes. There are different ways of classifying fallacies. Broadly speaking, we might divide fallacies into four kinds.
Logical Fallacies
Fallacies. Although there are more than two dozen types and subtypes of logical fallacies, these are the most common forms that you may encounter in writing, argument, and daily life: Begging the question, also known as circular reasoning, is a common fallacy that occurs when part of a claim—phrased in just slightly different words—is used ...
What Is a Logical Fallacy? 15 Common Logical Fallacies
A logical fallacy is an argument that can be disproven through reasoning. This is different from a subjective argument or one that can be disproven with facts; for a position to be a logical fallacy, it must be logically flawed or deceptive in some way. Compare the following two disprovable arguments.
Chapter 9 Informal Fallacies
Chapter 9. Informal Fallacies. A fallacy is a mistake in reasoning. A formal fallacy is a fallacy that can be identified merely by examining the argument's form or using a tool like a truth table. An informal fallacy cannot be detected from the argument's form. There are no foolproof tools for detecting informal fallacies.
CRITICAL THINKING
In this Wireless Philosophy video, Paul Henne (Duke University) describes the distinction between formal and informal fallacies. This distinction is useful f...
Logical Fallacies
Logical Fallacies. Fallacies are common errors in reasoning that will undermine the logic of your argument. Fallacies can be either illegitimate arguments or irrelevant points, and are often identified because they lack evidence that supports their claim. Avoid these common fallacies in your own arguments and watch for them in the arguments of ...
List of fallacies
Good books on critical thinking commonly contain sections on fallacies, and some may be listed below. DiCarlo, Christopher (2011). How to Become a Really Good Pain in the Ass: A Critical Thinker's Guide to Asking the Right Questions. Prometheus Books. ISBN 9781616143978. Engel, S. Morris (1994). Fallacies and Pitfalls of Language: The Language ...
Don't Be Duped—Know These 8 Logical Fallacies To Boost Your Critical
Logical fallacies are quite similar to cognitive biases which can be defined as the systematic departure from rational thinking.Logical fallacies compromise our ability to think critically and ...
Fallacies Card」をApp Storeで
‎Unlock the power of critical thinking with Fallacy Cards, the essential app for understanding and handling logical fallacies and cognitive biases. Perfect for students, professionals, and critical thinking enthusiasts, our app features concise, informative cards with clear definitions and real-world…