Informal Fallacies

A set of flashcards covering key concepts related to informal fallacies in reasoning.

Fallacy

A defect in an argument’s reasoning that consists of something other than merely false premises.

Formal fallacy

Identified purely by the argument’s form, such as affirming the consequent.

Informal fallacy

Detected only through the analysis of the content of an argument.

Fallacies of Relevance

Fallacies where premises aren’t logically relevant, but may be psychologically relevant to the conclusion.

Appeal to force (Argument ad baculum)

An appeal to force or the threat of force to accept a conclusion.

Appeal to Pity (Argument ad misericordiam)

A supplication for a conclusion based solely on evoking pity.

Appeal to the People (Argument ad populum)

A direct or indirect emotional appeal to gain acceptance of a conclusion without good evidence.

Argument against the person (Argument ad hominem)

Directs attention away from the argument to the person making it.

Ad hominem abusive

Verbal abuse directed at a person rather than addressing their argument.

Ad hominem circumstantial

Discrediting an opponent’s argument by alluding to certain circumstances affecting them.

Tu quoque

Accusing an opponent of hypocrisy, suggesting they cannot argue against something they do themselves.

Accident

Applying a general rule to a specific case it wasn’t intended to cover.

Straw Man

Distorting an opponent’s position to make it easier to refute.

Missing the point (Ignoratio Elenchi)

When premises support one conclusion, but a different conclusion is drawn.

Fallacies of Weak Induction

Arguments that fail because the connection between premises and conclusion isn't strong enough.

Appeal to unqualified authority (Argument ad verecundiam)

Appealing to an authority outside their area of expertise or who is untrustworthy.

Appeal to ignorance (Argument ad ignorantiam)

Arguing that something is true because it has not been proven false.

Hasty generalization (converse accident)

Generalizing from atypical or unusual cases to a broad rule.

False Cause

When the link between premises and conclusion is based on an imagined causal connection.

Slippery slope

Arguing that a small step will lead to a chain reaction without sufficient evidence.

Fallacies of Presumption

Fallacies that are based on false assumptions or presumptions.

Begging the Question (petitio principii)

Assuming as a premise the very conclusion being tried to prove.

Complex Question

A question that improperly combines two or more questions.

False Dichotomy (either-or fallacy)

Presenting two alternatives as the only options when others exist.

Fallacies of Ambiguity

Arise from ambiguity in the premises or conclusion.

Equivocation

A conclusion relying on a word or phrase used in two different senses.

Amphiboly

Misinterpreting a statement that is syntactically ambiguous.

Fallacies of grammatical analogy

Arguing similarly to valid arguments that are actually fallacious.

Composition

Arguing that because the parts have a certain attribute, the whole must also have that attribute.

Division

Arguing from a whole to its parts erroneously.