74 logical fallacies, with examples

Attacking the person making an argument instead of the argument itself.

Dismissing an argument because the person making it doesn't follow their own advice.

Misrepresenting someone's position to make it easier to attack.

Bringing up an irrelevant topic to divert attention from the real issue.

Presenting only two options when more exist.

Claiming one step will inevitably set off a chain of ever-worse consequences, without good evidence for each link.

Treating someone's word as proof when they aren't a reliable guide on the question, like a celebrity or an expert from another field.

Claiming something is true or good because many people believe it or do it.

Using feelings in place of good reasons.

Drawing a broad conclusion from too few, or unrepresentative, cases.

Using a personal story or vivid example in place of systematic evidence.

Assuming that because B followed A, A caused B.

Assuming what you're trying to prove.

Claiming something is true because it hasn't been proven false, or false because it hasn't been proven true.

Assuming something is good because it's natural, or bad because it's unnatural.

Claiming something is right because it's always been done that way.

Asking a question that smuggles in an unproven assumption.

If P then Q; Q is true; so P must be true. Invalid.

If P then Q; P is false; so Q must be false. Invalid.

Treating "if P then Q" as if it meant "if Q then P".

Turning "if P then Q" into "if not P then not Q".

P or Q; P is true; so Q must be false. Invalid when "or" allows both.

Not both P and Q; not P; so Q. Invalid, since both could be false.

Two things share a trait, so one must belong to the other.

The conclusion says something about all of a group that the premises only covered in part.

The conclusion generalizes about all of the subject when the premises only covered some.

Two negative premises can never support a conclusion.

A premise says what things are not, yet the conclusion says what they are.

A syllogism that sneaks in a fourth term, usually by using one word in two senses.

Concluding that something exists from premises that only say what would be true of it if it did.

"All A are B" does not mean "all B are A".

Switching between two meanings of the same word within one argument.

Exploiting a sentence whose grammar allows two readings.

Assuming that what's true of the parts must be true of the whole.

Assuming that what's true of the whole must be true of each part.

Dismissing a counterexample by redefining the group: "no TRUE member would do that".

Changing the standard of proof once it has been met.

Applying a rule to everyone except yourself or your side, without a good reason.

Applying a general rule to a case it was never meant to cover.

Judging a claim by where it came from instead of by its merits.

Dismissing an argument because of the arguer's circumstances or motives.

Discrediting someone in advance so that anything they say will be dismissed.

Rejecting a person or idea because of who else holds it or who they associate with.

Deflecting criticism by pointing to someone else's wrongdoing.

Treating two things as equal because they share a surface feature, ignoring big differences.

Assuming the truth must lie halfway between two positions.

Arguing that two things alike in some ways must be alike in another, when the similarities don't matter.

Presenting only the evidence that supports your case and leaving out the rest.

Arguing that a claim is true or false because believing it would have good or bad results.

Making a claim and then demanding that others disprove it.

"I can't imagine how that could be true, so it isn't."

Claiming something is better because it's new.

Using emotionally charged words to win an argument without actually making one.

Assuming that because two things occur together, one causes the other.

Getting cause and effect backwards.

Missing that a third factor causes both things.

Concluding a claim is false because someone argued for it badly.

Advancing a bold claim, retreating to a modest one when challenged, then going back to the bold one.

Overwhelming an opponent with a rapid flood of weak arguments.

Defending one position with several arguments that contradict each other.

Painting the target around the bullet holes: finding a pattern in random data after the fact.

Drawing conclusions only from the winners, because the losers aren't visible.

Treating what's easy to measure as all that matters.

Ignoring how common something is in the first place.

Confusing "the chance of this evidence if innocent" with "the chance of innocence given this evidence".

Judging a detailed combination of events as more likely than one of those events alone.

Believing past random results make a different result "due".

Crediting a cause for what was really just a natural return to average.

Continuing something only because of what you've already put into it.

Rejecting a solution because it isn't perfect.

"Everyone has a mother" doesn't mean "someone is everyone's mother".

Swapping in another name for the same thing inside "knows", "believes" or "wants" statements.

Relying on a claim that no possible evidence could ever count against.

Deriving what ought to be purely from what is.