critical thinking fallacies quizlet

Identify the fallacy of relevance committed by the following arguments.

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Critical Thinking and Decision-Making  - Logical Fallacies

Critical thinking and decision-making  -, logical fallacies, critical thinking and decision-making logical fallacies.

Critical Thinking and Decision-Making: Logical Fallacies

Lesson 7: logical fallacies.

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Logical fallacies

If you think about it, vegetables are bad for you. I mean, after all, the dinosaurs ate plants, and look at what happened to them...

Let's pause for a moment: That argument was pretty ridiculous. And that's because it contained a logical fallacy .

A logical fallacy is any kind of error in reasoning that renders an argument invalid . They can involve distorting or manipulating facts, drawing false conclusions, or distracting you from the issue at hand. In theory, it seems like they'd be pretty easy to spot, but this isn't always the case.

Watch the video below to learn more about logical fallacies.

Sometimes logical fallacies are intentionally used to try and win a debate. In these cases, they're often presented by the speaker with a certain level of confidence . And in doing so, they're more persuasive : If they sound like they know what they're talking about, we're more likely to believe them, even if their stance doesn't make complete logical sense.

False cause

One common logical fallacy is the false cause . This is when someone incorrectly identifies the cause of something. In my argument above, I stated that dinosaurs became extinct because they ate vegetables. While these two things did happen, a diet of vegetables was not the cause of their extinction.

Maybe you've heard false cause more commonly represented by the phrase "correlation does not equal causation ", meaning that just because two things occurred around the same time, it doesn't necessarily mean that one caused the other.

A straw man is when someone takes an argument and misrepresents it so that it's easier to attack . For example, let's say Callie is advocating that sporks should be the new standard for silverware because they're more efficient. Madeline responds that she's shocked Callie would want to outlaw spoons and forks, and put millions out of work at the fork and spoon factories.

A straw man is frequently used in politics in an effort to discredit another politician's views on a particular issue.

Begging the question

Begging the question is a type of circular argument where someone includes the conclusion as a part of their reasoning. For example, George says, “Ghosts exist because I saw a ghost in my closet!"

George concluded that “ghosts exist”. His premise also assumed that ghosts exist. Rather than assuming that ghosts exist from the outset, George should have used evidence and reasoning to try and prove that they exist.

Since George assumed that ghosts exist, he was less likely to see other explanations for what he saw. Maybe the ghost was nothing more than a mop!

False dilemma

The false dilemma (or false dichotomy) is a logical fallacy where a situation is presented as being an either/or option when, in reality, there are more possible options available than just the chosen two. Here's an example: Rebecca rings the doorbell but Ethan doesn't answer. She then thinks, "Oh, Ethan must not be home."

Rebecca posits that either Ethan answers the door or he isn't home. In reality, he could be sleeping, doing some work in the backyard, or taking a shower.

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 well.

M18 Critical Thinking & Reasoning

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.

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11.3 Persuasive Reasoning and Fallacies

Learning objectives.

• Define inductive, deductive, and causal reasoning.
• Evaluate the quality of inductive, deductive, and causal reasoning.
• Identify common fallacies of reasoning.

Persuasive speakers should be concerned with what strengthens and weakens an argument. Earlier we discussed the process of building an argument with claims and evidence and how warrants are the underlying justifications that connect the two. We also discussed the importance of evaluating the strength of a warrant, because strong warrants are usually more persuasive. Knowing different types of reasoning can help you put claims and evidence together in persuasive ways and help you evaluate the quality of arguments that you encounter. Further, being able to identify common fallacies of reasoning can help you be a more critical consumer of persuasive messages.

Reasoning refers to the process of making sense of things around us. In order to understand our experiences, draw conclusions from information, and present new ideas, we must use reasoning. We often reason without being aware of it, but becoming more aware of how we think can empower us to be better producers and consumers of communicative messages. The three types of reasoning we will explore are inductive, deductive, and causal.

Inductive Reasoning

Inductive reasoning reaches conclusions through the citation of examples and is the most frequently used form of logical reasoning (Walter, 1966). While introductory speakers are initially attracted to inductive reasoning because it seems easy, it can be difficult to employ well. Inductive reasoning, unlike deductive reasoning, doesn’t result in true or false conclusions. Instead, since conclusions are generalized based on observations or examples, conclusions are “more likely” or “less likely.” Despite the fact that this type of reasoning isn’t definitive, it can still be valid and persuasive.

Some arguments based on inductive reasoning will be more cogent, or convincing and relevant, than others. For example, inductive reasoning can be weak when claims are made too generally. An argument that fraternities should be abolished from campus because they contribute to underage drinking and do not uphold high academic standards could be countered by providing examples of fraternities that sponsor alcohol education programming for the campus and have members that have excelled academically (Walter, 1966). In this case, one overly general claim is countered by another general claim, and both of them have some merit. It would be more effective to present a series of facts and reasons and then share the conclusion or generalization that you have reached from them.

You can see inductive reasoning used in the following speech excerpt from President George W. Bush’s address to the nation on the evening of September 11, 2001. Notice how he lists a series of events from the day, which builds to his conclusion that the terrorist attacks failed in their attempt to shake the foundation of America.

Today, our fellow citizens, our way of life, our very freedom came under attack in a series of deliberate and deadly terrorist acts. The victims were in airplanes or in their offices: secretaries, business men and women, military and federal workers, moms and dads, friends and neighbors. Thousands of lives were suddenly ended by evil, despicable acts of terror. The pictures of airplanes flying into buildings, fires burning, huge—huge structures collapsing have filled us with disbelief, terrible sadness, and a quiet, unyielding anger. These acts of mass murder were intended to frighten our nation into chaos and retreat. But they have failed. Our country is strong. A great people has been moved to defend a great nation. Terrorist attacks can shake the foundations of our biggest buildings, but they cannot touch the foundation of America.

Using inductive reasoning, speakers reach conclusions through the citation of examples.

Claire Sambrook – UM… – CC BY-NC 2.0.

If a speaker is able to provide examples that are concrete, proxemic, and relevant to the audience, as Bush did in this example, audience members are prompted to think of additional examples that connect to their own lives. Inductive reasoning can be useful when an audience disagrees with your proposition. As you present logically connected examples as evidence that build to a conclusion, the audience may be persuaded by your evidence before they realize that the coming conclusion will counter what they previously thought. This also sets up cognitive dissonance, which is a persuasive strategy we will discuss later.

Reasoning by analogy is a type of inductive reasoning that argues that what is true in one set of circumstances will be true in another (Walter, 1966). Reasoning by analogy has been criticized and questioned by logicians, since two sets of circumstances are never exactly the same. While this is true, our goal when using reasoning by analogy in persuasive speaking is not to create absolutely certain conclusions but to cite cases and supporting evidence that can influence an audience. For example, let’s say you are trying to persuade a university to adopt an alcohol education program by citing the program’s success at other institutions. Since two universities are never exactly the same, the argument can’t be airtight. To better support this argument, you could first show that the program was actually successful using various types of supporting material such as statistics from campus offices and testimony from students and staff. Second, you could show how the cases relate by highlighting similarities in the campus setting, culture, demographics, and previous mission. Since you can’t argue that the schools are similar in all ways, choose to highlight significant similarities. Also, it’s better to acknowledge significant limitations of the analogy and provide additional supporting material to address them than it is to ignore or hide such limitations.

So how do we evaluate inductive reasoning? When inductive reasoning is used to test scientific arguments, there is rigorous testing and high standards that must be met for a conclusion to be considered valid. Inductive reasoning in persuasive speaking is employed differently. A speaker cannot cite every example that exists to build to a conclusion, so to evaluate inductive reasoning you must examine the examples that are cited in ways other than quantity. First, the examples should be sufficient, meaning that enough are cited to support the conclusion. If not, you risk committing the hasty generalization fallacy. A speaker can expect that the audience will be able to think of some examples as well, so there is no set number on how many examples is sufficient. If the audience is familiar with the topic, then fewer examples are probably sufficient, while more may be needed for unfamiliar topics. A speaker can make his or her use of reasoning by example more powerful by showing that the examples correspond to the average case, which may require additional supporting evidence in the form of statistics. Arguing that teacher salaries should be increased by providing an example of a teacher who works side jobs and pays for his or her own school supplies could be effectively supported by showing that this teacher’s salary corresponds to the national average (Walter, 1966).

Second, the examples should be typical, meaning they weren’t cherry-picked to match the point being argued. A speaker who argues to defund the National Endowment for the Arts (NEA) because the organization supports art that is “pornographic and offensive” may cite five examples of grants given for projects that caused such controversy. Failing to mention that these examples were pulled from the more than 128,000 grants issued by the NEA would be an inappropriate use of inductive reasoning since the examples aren’t sufficient or typical enough to warrant the argument. Another way to support inductive arguments is to show that the examples are a fair sample, meaning they are representative of the larger whole. Arguing that college athletes shouldn’t receive scholarships because they do not have the scholastic merit of other students and have less academic achievement could be supported by sharing several examples. But if those examples were not representative, then they are biased, and the reasoning faulty. A speaker would need to show that the athletes used in the example are representative, in terms of their race, gender, sport, and background, of the population of athletes at the university.

Deductive Reasoning

Deductive reasoning derives specifics from what is already known. It was the preferred form of reasoning used by ancient rhetoricians like Aristotle to make logical arguments (Cooper & Nothstine, 1996). A syllogism is an example of deductive reasoning that is commonly used when teaching logic. A syllogism is an example of deductive reasoning in which a conclusion is supported by major and minor premises. The conclusion of a valid argument can be deduced from the major and minor premises. A commonly used example of a syllogism is “All humans are mortal. Socrates is a human. Socrates is mortal.” In this case, the conclusion, “Socrates is mortal,” is derived from the major premise, “All humans are mortal,” and the minor premise, “Socrates is a human.” In some cases, the major and minor premises of a syllogism may be taken for granted as true. In the previous example, the major premise is presumed true because we have no knowledge of an immortal person to disprove the statement. The minor premise is presumed true because Socrates looks and acts like other individuals we know to be human. Detectives or scientists using such logic would want to test their conclusion. We could test our conclusion by stabbing Socrates to see if he dies, but since the logic of the syllogism is sound, it may be better to cut Socrates a break and deem the argument valid. Since most arguments are more sophisticated than the previous example, speakers need to support their premises with research and evidence to establish their validity before deducing their conclusion.

A syllogism can lead to incorrect conclusions if one of the premises isn’t true, as in the following example:

• All presidents have lived in the White House. (Major premise)
• George Washington was president. (Minor premise)
• George Washington lived in the White House. (Conclusion)

In the previous example, the major premise was untrue, since John Adams, our second president, was the first president to live in the White House. This causes the conclusion to be false. A syllogism can also exhibit faulty logic even if the premises are both true but are unrelated, as in the following example:

• Penguins are black and white. (Major premise)
• Some old television shows are black and white. (Minor premise)
• Some penguins are old television shows. (Conclusion)

Like in the game of Clue, real-life detectives use deductive reasoning to draw a conclusion about who committed a crime based on the known evidence.

Sleepmyf – Lego detective – CC BY-NC-ND 2.0.

Causal Reasoning

Causal reasoning argues to establish a relationship between a cause and an effect. When speakers attempt to argue for a particular course of action based on potential positive or negative consequences that may result, they are using causal reasoning. Such reasoning is evident in the following example: Eating more local foods will boost the local economy and make you healthier. The “if/then” relationship that is set up in causal reasoning can be persuasive, but the reasoning isn’t always sound. Rather than establishing a true cause-effect relationship, speakers more often set up a correlation, which means there is a relationship between two things but there are other contextual influences.

To use causal reasoning effectively and ethically, speakers should avoid claiming a direct relationship between a cause and an effect when such a connection cannot be proven. Instead of arguing that “x caused y,” it is more accurate for a speaker to say “x influenced y.” Causal thinking is often used when looking to blame something or someone, as can be seen in the following example: It’s the president’s fault that the economy hasn’t recovered more. While such a statement may garner a speaker some political capital, it is not based on solid reasoning. Economic and political processes are too complex to distill to such a simple cause-effect relationship. A speaker would need to use more solid reasoning, perhaps inductive reasoning through examples, to build up enough evidence to support that a correlation exists and a causal relationship is likely. When using causal reasoning, present evidence that shows the following: (1) the cause occurred before the effect, (2) the cause led to the effect, and (3) it is unlikely that other causes produced the effect.

Review of Types of Reasoning

• Inductive. Arguing from examples to support a conclusion; includes reasoning by analogy. Examples should be sufficient, typical, and representative to warrant a strong argument.
• Deductive. Deriving specifics from what is already known; includes syllogisms. Premises that lead to a conclusion must be true, relevant, and related for the argument to be valid.
• Causal. Argues to establish a relationship between a cause and an effect. Usually involves a correlation rather than a true causal relationship.

Fallacies of Reasoning

Fallacies are flaws within the logic or reasoning of an argument. Although we will discuss 10 common fallacies, more than 125 have been identified and named. It’s important to note that the presence of a fallacy in an argument doesn’t mean that it can’t be persuasive. In fact, many people are persuaded by fallacious arguments because they do not identify the fallacy within the argument. Fallacies are often the last effort of uninformed or ill-prepared speakers who find that they have nothing better to say. Being aware of the forms of reasoning and fallacies makes us more critical consumers of persuasive messages, which is a substantial benefit of studying persuasive speaking that affects personal, political, and professional aspects of our lives.

Hasty Generalization

The hasty generalization fallacy relates to inductive reasoning and is the result of too few examples being cited to warrant the generalization. Jumping to conclusions is tempting, especially when pressed for time, but making well-researched and supported arguments is key to being an effective and ethical speaker. Making a claim that train travel is not safe and citing two recent derailments that resulted in injury doesn’t produce a strong warrant when viewed in relation to the number of train passengers who travel safely every day.

False Analogy

The false analogy fallacy also relates to inductive reasoning and results when the situations or circumstances being compared are not similar enough. A common false analogy that people make is comparing something to putting a person on the moon: “If we can put a person on the moon, why can’t we figure out a way to make the tax code easier to understand?” This question doesn’t acknowledge the different skill sets and motivations involved in the two examples being compared.

False Cause

The false cause fallacy relates to causal reasoning and occurs when a speaker argues, with insufficient evidence, that one thing caused or causes another. When I was in high school, teachers used to say that wearing baseball caps would make us go bald when we got older. In an attempt to persuade us to not wear hats in the classroom, they were arguing, fallaciously, that wearing baseball caps is what causes baldness. When a false cause argument is made after the “effect,” it is referred to in Latin as post hoc ergo propter hoc , which means “after this, therefore because of this.” Blaming bad fortune on superstitions is a good example of faulty reasoning that tries to argue for a connection between an “effect” that has already occurred and its preceding “cause.” My bad luck is more likely attributable to poor decisions I have made or random interference than the mirror I broke while moving two years ago.

Superstitious beliefs often exemplify the false cause fallacy. Is the broken mirror really the cause of your bad luck?

Tim Sheerman-Chase – Seven Years Bad Luck – CC BY 2.0.

False Authority

The false authority fallacy results when the person making an argument doesn’t actually have the qualifications to be credible but is perceived as credible because they are respected or admired. Despite the fact that this form of argument is fallacious, it is obviously quite effective. Advertisers spend millions of dollars to get celebrities and athletes to sell us their products because of the persuasive potential these stars carry in their persona, not in their ability to argue a point. Voters might be persuaded to support a candidate because of a famous musician’s endorsement without questioning the political beliefs of either the musician or the politician to see if they match up with their own.

Parents and other sources of guidance in our lives have tried to keep us from falling for the bandwagon fallacy. When your mom responds to your argument that you should get to go to the party because everyone else is by asking, “If everyone else jumped off a bridge, would you?” she is rightfully pointing out the fallacy in your argument. In a public-speaking-related example, I have had students try to persuade their audience to buy and eat more organic foods based on their increasing popularity. In short, popular appeal and frequency of use are not strong warrants to support an argument. Just because something is popular, doesn’t mean it’s good.

False Dilemma

The false dilemma fallacy occurs when a speaker rhetorically backs his or her audience into a corner, presenting them with only two options and arguing that they must choose either one or the other. This is also known as the “either/or” fallacy. Critical thinkers know that the world can’t be simplified to black and white, good and bad, or right and wrong. Yet many people rely on such oversimplifications when making arguments. A speaker who argues that immigrants to the United States should learn English or go back to their own country doesn’t acknowledge that there are many successful immigrants who have successful lives and contribute to society without speaking English fluently. The speaker also ignores the fact that many immigrants do not have access to English language instruction or the time to take such classes because they are busy with their own jobs and families. Granted, such a rhetorical strategy does make it easier to discuss complex issues and try to force people into a decision, but it also removes gray area in the form of context that can be really important for making a decision. Be critical of speakers and messages that claim there are only two options from which to choose.

Ad hominem means “to the person” in Latin and refers to a common fallacy of attacking a person rather than an argument. Elementary school playgrounds and middle school hallways are often sites of ad hominem attacks. When one person runs out of good reasons to support their argument and retorts to the other, “Well you’re ugly!” they have resorted to a fallacious ad hominem argument. You probably aren’t surprised to know that politicians frequently rely on personal attacks, especially when they are sponsored by political action committees (PACs). The proliferation of these organizations resulted in an increase in “attack ads” during the 2012 presidential race. While all fallacious arguments detract from the quality of public communication, ad hominem arguments in particular diminish the civility of our society.

Slippery Slope

The slippery slope fallacy occurs when a person argues that one action will inevitably lead to a series of other actions. If we take one step down an icy hill it becomes difficult to get back up and you slide all the way down even though you only wanted to take one step. A slippery slope fallacy in a speech about US foreign policy might take the form of the following argument: If the United States goes to help this country in need, then we will be expected to intervene any time there’s a conflict in the world.

Red Herring

The red herring fallacy is my favorite because it has an interesting origin—and it was used in Scooby Doo ! The origin of the name of this fallacy comes from old foxhunting practices in England. When the hunters were training their dogs to stay on the trail of a fox, they would mark a trail with fox scent so the dog could practice following the scent. As a further test, they would take the smell of fish (like a red herring) and create a second trail leading in another direction. If a dog left the scent of the fox trail to follow the stronger and more noticeable scent trail left by the red herring, then the dog failed the test. The smartest and best-trained dogs weren’t distracted by the fishy trail and stayed on the path. Basically every episode of Scooby Doo involves a red herring trick—for example, when the ghost at the amusement park turns out to be a distraction created by the owner to cover up his financial problems and shady business practices. A speaker who uses the red herring fallacy makes an argument that distracts from the discussion at hand. Bringing up socialism during an argument about nationalized health care is an example of a red herring fallacy.

Appeal to Tradition

The appeal to tradition fallacy argues that something should continue because “it’s the way things have been done before.” Someone may use this type of argument when they feel threatened by a potential change. People who oppose marriage rights for gay and lesbian people often argue that the definition of marriage shouldn’t change because of its traditional meaning of a “union between one man and one woman.” Such appeals often overstate the history and prevalence of the “tradition.” Within the United States, many departures from traditional views of marriage have led to changes that we accept as normal today. Within the past one hundred years we have seen law changes that took away men’s rights to beat their wives and make decisions for them. And it wasn’t until 1993 that every state made marital rape a crime, which changed the millennia-old “tradition” that women were obligated to have sex with their husbandsf (Coontz, 2006). Many people are resistant to or anxious about change, which is understandable, but this doesn’t form the basis of a good argument.

Review of Fallacies

• Hasty generalization. Inductive reasoning fallacy that occurs when too few examples are cited to warrant a conclusion.
• False analogy. Inductive reasoning fallacy that occurs when situations or circumstances being compared are not similar enough.
• False cause. Causal reasoning fallacy that occurs when a speaker argues with insufficient evidence that one thing caused/causes another.
• False authority. Fallacy that occurs when a person making an argument doesn’t have the knowledge or qualifications to be credible but is perceived as credible because they are respected or admired.
• Bandwagon. Fallacy that relies on arguing for a course of action or belief because it is commonly done or held.
• False dilemma. Fallacy that occurs when a speaker presents an audience only two options and argues they must choose one or the other.
• Ad hominem. Fallacy that occurs when a speaker attacks another person rather than his or her argument.
• Slippery slope. Fallacy that occurs when a person argues that one action will inevitably lead to a series of other actions.
• Red herring. Fallacy that occurs when a speaker poses an argument that is meant to distract from the argument at hand.
• Appeal to tradition. Fallacy that results when a speaker argues that something should continue because “it’s the way things have been done before.”

Key Takeaways

We use reasoning to make sense of the world around us and draw conclusions. Three types of reasoning are inductive, deductive, and causal.

• Inductive reasoning refers to arguments that persuade by citing examples that build to a conclusion. Examples should be sufficient, typical, and representative to warrant a strong argument. Reasoning by analogy argues that what is true in one set of circumstances will be true in another, and is an example of inductive reasoning.
• Deductive reasoning refers to arguments that derive specifics from what is already known and includes syllogisms. Premises that lead to the conclusion must be true and relevant for the argument to be valid.
• Causal reasoning refers to arguments that establish a relationship between a cause and an effect and usually involves a correlation rather than a true causal relationship.
• Fallacies refer to flaws within the logic or reasoning of an argument. Ten fallacies of reasoning discussed in this chapter are hasty generalization, false analogy, false cause, false authority, false dilemma, ad hominem, slippery slope, red herring, and appeal to tradition.
• Identify examples of inductive, deductive, and causal reasoning in the sample persuasive speech on education in prisons included in Section 4.3 “Nonverbal Communication Competence” .
• People often use fallacies in arguments, usually without knowing it. Being able to identify fallacies is an important critical thinking skill. Find a letter to the editor in a paper or online and see if you can identify any of the ten fallacies discussed in this chapter.
• Of the ten fallacies discussed in the chapter, which do you think is the most unethical and why?

Coontz, S., “Traditional Marriage Has Changed a Lot,” Seattle Post Intelligencer , February 23, 2006, accessed March 6, 2012, http://www.seattlepi.com/default/article/Traditional-marriage-has-changed-a-lot-1196563.php .

Cooper, M. D., and William L. Nothstine, Power Persuasion: Moving an Ancient Art into the Media Age (Greenwood, IN: Educational Video Group, 1996), 27.

Walter, O. M., Speaking to Inform and Persuade (New York: Macmillan, 1966), 58.

Communication in the Real World Copyright © 2016 by University of Minnesota is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License , except where otherwise noted.

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Logical Fallacies

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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.

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• 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.

Table of contents

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 30, 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

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