Logical Fallacies Full Set

Overgeneralization

Occurs when there is a reasonable likelihood that a sample is not representative of a larger group. (also known as hasty generalization)

"The carton of milk that I bought from Acme was spoiled before I even opened it! Milk from Acme is bad."

Fallacy of Insufficiency

Equivocation

Occurs when the conclusion of an argument depends on a word or phrase having two meanings (explicitly or implicitly) in the argument.

"We have a duty to do what is right. We have a right to speak out in defense of the innocent. Therefore we have a duty to speak out in defense of the innocent."

Fallacy of Accuracy

False Dilemma

Occurs when an arguer poses only two choices as if they are the only two choices available, hiding the complexity of the issue that exists in between and beyond the two choices presented. Also known as a false dichotomy.

"You can either vote for me, or this country is going down the tubes."

Problem: Overlooks alternatives

Fallacy of Accuracy

Begging the Question

Occurs when the arguer creates the illusion they her premises are supported by leaving out a key premise, restating the conclusion as though it were a premise, or through circular reasoning.

"Cheating is wrong. That said, helping your friend on homework is wrong."

"It's obvious that the poor in this country should be given handouts from the government. After all, these people earn less than most citizens."

Fallacy of Accuracy

Appeal to Emotion

An arguer attempts to support a conclusion by evoking pity from the audience. This pity can be directed towards the arguer or a third party. Emotions often used are: pity, fear, terror, ridicule, vanity, flattery, etc.

"The Dramdati people of the North are invading our towns! They are corrupting our values and taking our jobs!! Vote for me if you want something done about it!"

Fallacy of Relevance

Ad Hominem

The arguer, instead of responding to the form or content of the argument or the issue at hand, focuses an attack directed at her opponent to discredit her character, in the hope that it discredits the quality of her arguments.

Interviewer: "What do you think about the economic situation in Albania?

Arguer: My opponent has never voted on a bill that would help Albania. In fact, she doesn't even know where Albania is!

Fallacy of Relevance

Straw Man

An arguer distorts her opponents argument for the purpose of more easily attacking it and after attacking the "straw man", concludes that his argument has defeated his opponent.

"Need for healthcare reform! You want to talk about healthcare reform! This country is debt over its ears!"

Fallacy of Relevance

Red Herring

Arguer intentionally diverts the attention of the listener by changing the subject to a different but sometimes related subject.

Son: "Wow, Dad, it's really hard to make a living on my salary."

Father: "Consider yourself lucky, son. Why, when I was your age, I only made $40 a week."

Fallacy of Relevance

Appeal to Ignorance

Occurs when the premises of an argument claims that nothing has been proven one way or another, yet the conclusion makes a clear assertion one way.

"For decades, humanity has been trying to find evidence that environmental conditions are most important in developing a good student, and it has never been done. Therefore, it must be the case that environmental conditions are simply not important for a child to become a quality student."

Fallacy of Insufficiency

False Cause

Occurs when the link between premises and conclusion depends on an imagined or proven causal connection.

"Had she not been eating fast food so regularly in the last two years, Marge would not have gotten cancer."

Also known as, Post hoc ergo propter hoc.

Fallacy of Insufficiency

Post hoc ergo propter hoc

Occurs when a conclusion is made that relies on the belief that that a cause led to the conclusion simply because it came prior to the conclusion being realized.

"Since we've moved in together, she's been the happiest I've ever seen her. Thank goodness we choose to live together!"

Fallacy of Insufficiency

Denying the antecedent

arguments of this form are invalid because they do not give good reason to establish their conclusions, even if their premises are true. See examples in the Rulebook.

Fallacy of Accuracy

Affirming the Consequent

invalid argument due to the form If P, then Q, Q, Therefore, P

Fallacy of Accuracy

Circular Reasoning/ Argument

Occurs when an arguer's repetition of a claim is presented as evidence. This leads to a lack of substance.

"One ought to behave properly to be a good person because being a good person is to behave properly."

Fallacy of Insufficiency

Loaded Language

Language that primarily plays on the emotions. Does not make an argument at all and is used manipulatively.

Fallacy of Relevance

Bandwagon Appeal

(ad populum) The arguer appeals to the reader's desires: to be popular, loved, esteemed, admired, valued, recognized, accepted by others. The appeal often takes the form of, "you want to be like everybody else, don't you?" or "you don't want to be like...", in attempting to convince the reader that they ought to accept the conclusion. Other forms of this argument include the Appeal to Vanity and Appeal to Luxury.

"Vote for Marty Smith, your neighbors are!"

Fallacy of Insufficiency

Mere re-description

offering a premise that really only rephrases the conclusion, rather than offering specific independent reason for it.

Fallacy of Insufficiency

persuasive definition

defining a term in a way that may seem to be straightforward but in fact is loaded.

Fallacy of Relevance

Poisoning the well

Using loaded language to disparage an argument before offering the argument itself.

Fallacy of Relevance

Composition

Occurs when the conclusion of an argument depends on a false transference of an attribute from the parts of something onto the whole. The issue is in transferring the attribute.

"Seven out of the Yankees nine starting players are batting over .300. The Yankees are a good team."

Fallacy of Accuracy

Division

Occurs when the conclusion of an argument depends on the erroneous transference of an attribute from a whole onto its parts. The reverse/ opposite of composition.

"Montgomery High School is a great school. The students at Montgomery High School are great."

Fallacy of Accuracy

Ad Hominem tu quoqe

One arguer attempts to discredit their opponent's argument through a character attack in which they claim that her opponent is hypocritical or arguing in bad faith.

Arguer A to Opponent: "You tell the public that you are in fact a supporter of clean drinking water. However, in 1994 you voted for a bill that funded a company that has one of the worst environmental records in recent history!"

Fallacy of Relevance

Fallacy of Accident

Is committed when a general rule is applied to a specific case that it was not intended to cover.

"I believe that no one should harm anyone else, that's why I don't support the military, and furthermore, why I don't support this government."

Fallacy of Relevance

Missing the Point

Occurs when an arguer intentionally draws an illogical conclusion from the premises.

"There has been a recent decline in crime among middle aged men. It's clear that this is due to the increasing size of our town."

Fallacy of Relevance

Ad Hominem Circumstantial

Instead of specifically attacking the character of one's opponent, this argument attacks circumstances that affect the the opponent inferring that the opponent is biased or predisposed in a manner that makes her argument unreasonable.

Mildred: We ought to allow the new development to be 30% residential and 70% commercial.

Thomas: Of course you'd say that you grew up in the most capitalist country in the world!

Also known as the Genetic Fallacy

Occurs when the origin of an idea is used to discredit the value of the idea.

"Martin Smith came from one of the leading secessionist towns in South Carolina in 1861. His ideas on American Nationalism can't be trusted."

Fallacy of Relevance

Guilt by Association

A form of Ad Hominem, this occurs when an arguer's conclusion directly or indirectly implies that one's connection to a person or set of circumstances discredits their opponent's argument.

"Mark Johnson can not be trusted on fiscal policy. He was, in fact, working for the chief financial officer of Debts R' Us when it went bankrupt."

Fallacy of Relevance

False Analogy

Occurs when an analogy between two things or situations is not strong enough to support the conclusion that is drawn.

"Guns are like hammers—they're both tools with metal parts that could be used to kill someone. And yet it would be ridiculous to restrict the purchase of hammers—so restrictions on purchasing guns are equally ridiculous."

Fallacy of Relevance

Appeal to Unqualified Authority

Occurs when the cited authority or witness lacks credibility. Often for reasons such as: lack of expertise, bias, motive, or ability.

"My great, great, grandmother used to say that there were certain properties of matter that were beyond scientific discovery."

Fallacy of Insufficiency

Slippery Slope

Occurs when the conclusion of an argument rests upon an alleged chain reaction and there is no good reason to believe that the chain reaction will take place.

"If we let some people into the amusement park early, everyone will think that they can come early too."

Fallacy of Insufficiency

No True Scotsman

Occurs when one isolates a character attribute that is valued and argues that a person who works against it would obviously not belong to a valued group.

"No good Republican would advocate for "X".

Fallacy of Insufficiency

Appeal to Nature

Occurs when an arguer claims that their conclusion is justified by scientific naturalism or "natural" processes.

"There will always be violence in the world, that's just the way we are built."

Fallacy of Insufficiency

Fallacy of Relevance

Fallacy in which the argument uses irrelevant evidence to justify a claim, often intentionally.

Fallacy of Insufficiency

Fallacy in which the argument uses insufficient evidence (quality) to justify a claim.

Fallacy of Accuracy

When wrong and inaccurate conclusions drawn from the premises or false assumptions.

Can I:

Identify a specific fallacy when reading or hearing an argument?

Identify the category type of fallacy when reading or hearing an argument?

Explain why it is fallacious within the context of the argument offered?

Offer advice or explain how the author could fix the fallacy?

Toulmin Model of Argument

non sequitur

drawing a conclusion that "does not follow"- a conclusion that is not a reasonable inference from the evidence.

False Equivalence

An argument or claim in which two completely opposing arguments or pieces of evidence are presented as equivalent when in fact they are not.