Informal Logical Fallacies

Ad Hominem (Against the Man)

Ad Hominem (Against the Man)

An argument in which the arguer himself is attacked on the basis of reputation, and the man’s argument itself is ignored

Appeal to Authority

An argument in which a key premise is based on a statement from an authority, if that authority is not a specialist in the field at issue

Appeal to Fear

An argument in which a key premise is a threat against someone

Appeal to Tradition

An argument in which one of the key premises asks one to accept the conclusion because “it has always been done this way.”

Appeal to Novelty

the argument claims that a course of action should be adopted because it is new and untried

Argument from Ignorance

This is an argument in which one contends that a belief is justified because it cannot be disproven

Bandwagon Fallacy

An argument in which rejection by one’s peers is threatened as part of the argument, implicitly or explicitly

Begging the Question

Also called a circular argument, this kind of argument assumes the truth of the conclusion as part of the premises of the argument for it

Biased Sample

An argument in which conclusions are drawn based on faulty samples

Hasty Generalization

in which the arguer bases a conclusion on a small number of initial samples

Burden of Proof

This fallacy involves a premise that contends that because one cannot prove that a thing does not exist, that thing does in fact exist. The burden of proof is the other way around

Complex Question

A question that makes unfair assumptions or implications about the nature of an opponent

Composition Fallacy

An error that equates traits of the part to the whole, or traits of the whole to the part

False Dilemma

The false dilemma argument includes a premise that states that one must accept one of two conclusions, when in fact these are not the only two possibilities in the circumstances

Gambler’s Fallacy

When one draws a conclusion based on faulty odds calculations

Misleading Vividness

This is an appeal to an especially emotional experience or anecdote; the vivid details are emotionally convincing, but do not lend any weight to the argument itself

Post Hoc (Post Hoc Ergo Propter Hoc)

meaning “After the fact, therefore because of it”. This fallacy involves drawing a conclusion based on observation; one event follows the first, therefore it is \n assumed that the first caused the second

Relativist Fallacy

The relativist fallacy involves the “it’s true for me” claim. Sometimes these claims can be true, but when this claim is made about external facts, it is almost certainly wrong. Tastes may be relative; truth is not

Slippery Slope

The slippery slope fallacy involves concluding that a circumstance will come to pass as a result of another circumstance, when in fact the first may not cause the second

Straw Man

This fallacy involves ignoring the strongest arguments of an opponent, and pretending that the opponent’s argument is something other than what it is