Collection · 14 fallacies

Fallacies in Debate

Debate rewards fallacies in a way that writing does not. An argument on the page can be re-read; an argument delivered aloud gets one pass, and a move that sounds like a reply will usually be scored as one before anybody has time to check.

That is why the same handful turn up again and again. They are not the most interesting fallacies, or the hardest to understand. They are the ones that survive contact with an audience and a clock.

Grouped below by what each one is actually doing — because recognising the tactic is faster than recalling the name, and under time pressure speed is the whole problem.

Attacking the arguer

The oldest substitution in debate: answer the person, and let the audience hear it as answering the point.

Ad HominemThe quickest way to change the subject while appearing to engage. Under a clock it also costs your opponent the rebuttal they had prepared. Tu QuoqueAnswering a charge by levelling it back. It feels like a reply because it has the rhythm of one, but the original claim is left standing. WhataboutismThe counter-charge is usually true, which is what makes it feel like a contribution rather than an evasion. The original point is still on the table.

Misrepresenting the position

Both of these work by editing what the other side said — and both are hard to call out, because the distortion starts from something real.

StrawmanAlmost always arrives in the rebuttal, assembled from something you did say with a qualification quietly removed. No True ScotsmanThe move that rescues a generalisation after a counterexample has landed, by redefining the category mid-argument.

Avoiding the question

Not refusing to answer — appearing to answer while the actual question goes past.

Red HerringA genuinely interesting tangent is the most effective kind, because the audience follows it willingly and never notices the turn. Loaded QuestionPuts the assumption inside the grammar. Denying it reads as evasion; answering it concedes the point. Burden of Proof“Prove it isn’t true.” Shifts the work onto whoever is sceptical, and is most common where the claim cannot be supported directly.

Forcing the conclusion

Arguments that narrow the field until only one answer appears to remain.

False DilemmaTwo options offered as the whole field. The parallel phrasing is what sells it — matched grammar sounds exhaustive. Slippery SlopeJumps from a modest proposal to an unacceptable endpoint without ever defending the steps in between.

Exploiting the format

These two attack the structure of the debate rather than the argument — the clock in one case, the standard of proof in the other. Both are nearly invisible inside a single exchange.

Gish GallopRefuting a claim costs far more than making one, so equal speaking time is not a level field. Answering honestly means running out of clock. Moving the GoalpostsEvery demand is reasonable on its own; the sequence is the tell. Fix the standard in advance and the tactic has nowhere to go.

Borrowing weight

Neither of these is automatically a fallacy. Both become one the moment they stand in place of the argument rather than supporting it.

Appeal to AuthorityCiting standing instead of reasoning. Hard to challenge live, because disputing it sounds like disputing the expert. Appeal to EmotionNot a fallacy because it moves people. A fallacy when it is offered instead of the evidence.

Why These Ones

Debate selects for a particular kind of error.

There are hundreds of named fallacies. Only a few are common in live argument, and they share a property: each one produces something that passes for an answer at the speed an audience listens.

A fallacy that requires a diagram to land will never survive a debate. A fallacy that can be delivered in one sentence, sounds responsive, and puts the other side on the back foot will survive indefinitely — which is why this list has barely changed since Aristotle wrote most of it down.

Knowing the names matters less than recognising the shape in the moment. That is the argument for grouping them by tactic rather than alphabetically, and for reading the whole page once rather than looking entries up one at a time.

See also the full fallacy library, the cognitive biases that make these moves persuasive, and the rhetorical devices several of them are built from.