Common Logical Fallacies

A collection of 19 common logical fallacies and related logic terminology as discussed in the lecture notes.

Logic Fallacy

A kind of reasoning or pattern of reasoning that will lead you astray.

Ad Hominem

The fallacy of attacking the person who is arguing rather than the argument itself, such as insulting their character or actions.

Straw Man

Mischaracterizing an argument in order to make it appear weaker than it actually is.

Steel Manning

The opposite of straw manning, also known as the principle of Charity, which involves describing an opponent's beliefs in the strongest possible terms.

Appeal to Authority

Appealing to someone's position or expertise in order to establish the truth of a claim.

False Dilemma

Presenting two choices as if those were the only exhaustive options available.

Equivocation

Using the same word but with different meanings within an argument.

Circular Argument

Assuming what is being disputed or what needs to be proved; also known as begging the question.

Begging the Question

A bad form of reasoning where one assumes the reliability of a source in order to assert that the source is reliable.

Hasty Generalization

A generalization that is made with insufficient evidence.

Comparative Fallacy

Making a comparison and then trying to establish an absolute claim from it.

Post-hoc ergo propter hawk

The fallacy of attributing causation just because one event precedes another.

Appeal to Ignorance

Claiming that something is true just because it hasn't been proven to be false.

Appeal to Nature

The claim that just because something is natural, it is inherently good.

Appeal to Popularity

Appealing to popular opinion to establish the truth of a claim.

Guilt by Association

Discrediting an idea because it is shared by a group deemed mad, despicable, or undesirable.

No True Scotsman

Revising definitions in an ad hoc fashion to avoid counter-examples or criticism of a specific group.

Fallacy of Composition

Assuming that what is true of the parts must also be true of the whole.

Fallacy of Division

Assuming that whatever is true of the whole must be true of the parts.

Appeal to Hypocrisy

Trying to dispute a claim because the person arguing for it fails to act consistently with that claim.

Burden of Proof Fallacy

Claiming that the weight of evidence lies with the person trying to disprove a claim rather than the person trying to prove it.

Fallacy Fallacy

Assuming that a conclusion is false just because a bad argument was made in support of it.