What Is a Logical Fallacy?

Logical fallacies are flawed, deceptive, or false arguments that can be proven wrong with reasoning. There are two main types of fallacies:

• A formal fallacy is an argument with a premise and conclusion that doesn’t hold up to scrutiny.
• An informal fallacy is an error in the form, content, or context of the argument.

15 Types of Logical Fallacies

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Ad Hominem

An ad hominem fallacy uses personal attacks rather than logic. This fallacy occurs when someone rejects or criticizes another point of view based on the personal characteristics, ethnic background, physical appearance, or other non-relevant traits of the person who holds it.

Ad hominem arguments are often used in politics, where they are often called “mudslinging.” They are considered unethical because politicians can use them to manipulate voters’ opinions against an opponent without addressing core issues.

Study Tool

See if you can tell which of these is an ad hominem argument and which is just an insult.

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Straw Man

A straw man argument attacks a different subject rather than the topic being discussed — often a more extreme version of the counter argument. The purpose of this misdirection is to make one’s position look stronger than it actually is.

The straw man argument is appropriately named after a harmless, lifeless scarecrow. Instead of contending with the actual argument, they attack the equivalent of a lifeless bundle of straw — an easily defeated puppet that the opponent was never arguing for in the first place.

Study Tool

See if you can detect how both of the following statements could qualify as strawmen arguments.

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Appeal to Ignorance

An appeal to ignorance (also known as an “argument from ignorance”) argues that a proposition must be true because it has not been proven false or there is no evidence against it.

The argument can be used to bolster multiple contradictory conclusions at once, such as the following two claims:

• “No one has ever been able to prove that extraterrestrials exist, so they must not be real.”
• “No one has ever been able to prove that extraterrestrials do not exist, so they must be real.”

An appeal to ignorance doesn’t prove anything. Instead, it shifts the need for proof away from the person making a claim.

Study Tool

Which of the following examples is an appeal to ignorance?

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False Dilemma/False Dichotomy

A false dilemma or false dichotomy presents limited options — typically by focusing on two extremes — when in fact more possibilities exist. The phrase “America: Love it or leave it” is an example of a false dilemma.

The false dilemma fallacy is a manipulative tool designed to polarize the audience, promoting one side and demonizing another. It’s common in political discourse as a way of strong-arming the public into supporting controversial legislation or policies.

Study Tool

See if you can come up with a third option that these examples failed to mention.

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Slippery Slope

A slippery slope argument assumes that a certain course of action will necessarily lead to a chain of future events. The slippery slope fallacy takes a benign premise or starting point and suggests that it will lead to unlikely or ridiculous outcomes with no supporting evidence.

You may have used this fallacy on your parents as a teenager: “But you have to let me go to the party! If I don’t go to the party, I’ll be a loser with no friends. Next thing you know, I’ll end up alone and jobless, living in your basement when I’m 30!”

Study Tool

Which of these examples is a slippery slope fallacy and which is not?

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Circular Argument

Circular arguments occur when a person’s argument repeats what they already assumed before without arriving at a new conclusion. For example, if someone says, “According to my brain, my brain is reliable,” that’s a circular argument.

Circular arguments often use a claim as both a premise and a conclusion. This fallacy only appears to be an argument when in fact it’s just restating one’s assumptions.

Study Tool

See if you can identify which of these is a circular argument.

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Hasty Generalization

A hasty generalization is a claim based on a few examples rather than substantial proof. Arguments based on hasty generalizations often don’t hold up due to a lack of supporting evidence: The claim might be true in one case, but that doesn’t mean it’s always true.

Hasty generalizations are common in arguments because there’s a wide range of what’s acceptable for “sufficient” evidence. The rules for evidence can change based on the claim you’re making and the environment where you are making it — whether it’s rooted in philosophy, the sciences, a political debate, or discussing house rules for using the kitchen.

Study Tool

Which of the following is a hasty generalization?

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Red Herring

A red herring is an argument that uses confusion or distraction to shift attention away from a topic and toward a false conclusion. Red herrings usually contain an unimportant fact, idea, or event that has little relevance to the real issue.

Red herrings are a common diversionary tactic when someone wants to shift the focus of an argument to something easier or safer to address. But red herrings can also be unintentional.

Study Tool

Which of the following examples is a red herring fallacy?

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Appeal to Hypocrisy

An appeal to hypocrisy — also known as the tu quoque fallacy — focuses on the hypocrisy of an opponent. The tu quoque fallacy deflects criticism away from oneself by accusing the other person of the same problem or something comparable.

The tu quoque fallacy is an attempt to divert blame. The fallacy usually occurs when the arguer uses apparent hypocrisy to neutralize criticism and distract from the issue.

Study Tool

Which of the following is an appeal to hypocrisy?

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Causal Fallacy

Causal fallacies are informal fallacies that occur when an argument incorrectly concludes that a cause is related to an effect. Think of the causal fallacy as a parent category for other fallacies about unproven causes.

One example is the false cause fallacy, which is when you draw a conclusion about what the cause was without enough evidence to do so. Another is the post hoc fallacy, which is when you mistake something for the cause because it came first — not because it actually caused the effect.

Study Tool

Which kind of causal fallacy is at work in these examples?

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Sunk Cost

A sunk cost fallacy is when someone continues doing something because of the effort they already put in it, regardless of whether the additional costs outweigh the potential benefits. “Sunk cost” is an economic term for any past expenses that can no longer be recovered.

For example: Imagine that after watching the first six episodes of a TV show, you decide the show isn’t for you. Those six episodes are your “sunk cost.” A sunk cost fallacy would be deciding to finish watching anyway because you’ve already invested roughly six hours of your life in it.

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Which of these is a sunk cost fallacy and which is not?

Appeal to authority is the misuse of an authority’s opinion to support an argument. While an authority’s opinion can represent evidence and data, it becomes a fallacy if their expertise or authority is overstated, illegitimate, or irrelevant to the topic.

For example, citing a foot doctor when trying to prove something related to psychiatry would be an appeal to authority fallacy.

Study Tool

How do these statements mishandle authorities?

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Equivocation

Equivocation happens when a word, phrase, or sentence is used deliberately to confuse, deceive, or mislead. In other words, saying one thing but meaning another.

When it’s poetic or comical, we call this a “play on words.” But when it’s done in a political speech, an ethics debate, or an economics report — and it’s designed to make the audience think you’re saying something you’re not — that’s when it becomes a fallacy.

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How does each of these examples commit an equivocation fallacy?

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Appeal to Pity

An appeal to pity relies on provoking your emotions to win an argument rather than factual evidence. Appealing to pity attempts to pull on an audience’s heartstrings, distract them, and support their point of view.

Someone accused of a crime using a cane or walker to appear more feeble in front of a jury is one example of appeal to pity. The appearance of disability isn’t an argument on the merits of the case, but it’s intended to sway the jury’s opinion anyway.

Study Tool

Which of these is a fallacious appeal to emotion and which one is not?

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Bandwagon Fallacy

The bandwagon fallacy assumes something is true (or right or good) because others agree with it. In other words, the fallacy argues that if everyone thinks a certain way, then you should, too.

One problem with this kind of reasoning is that the broad acceptance of a claim or action doesn’t mean that it’s factually justified. People can be mistaken, confused, deceived, or even willfully irrational in their opinions, so using them to make an argument is flawed.

Study Tool

Which of these is a bandwagon fallacy?