Informal Fallacies: Relevance

When the Evidence Does Not Connect

A fallacy of relevance occurs when the premises of an argument are not actually relevant to the conclusion. The argument might feel persuasive because it triggers emotional responses or exploits cognitive shortcuts, but the logical connection is missing.

Ad hominem attacks the person making the argument instead of the argument itself. 'Senator Jones's healthcare proposal is flawed because she has no medical degree.' Whether Senator Jones has a medical degree is irrelevant to whether her proposal is sound. Ad hominem is the most common fallacy in political discourse because attacking a person is easier than refuting their argument.

Straw man misrepresents an opponent's position to make it easier to attack. 'My opponent wants to reduce military spending, so clearly he wants to leave America defenseless.' The opponent probably wants a smaller reduction, not zero defense spending. The attacker has replaced the real position with an extreme caricature.

More Fallacies of Relevance

Red herring introduces an irrelevant topic to divert attention from the original issue. A politician asked about their voting record on education might respond with a speech about their military service. The response sounds substantive but does not address the question.

Appeal to authority cites an authority figure who is not actually an expert on the topic at hand. A celebrity endorsing a vaccine is not evidence that the vaccine works. A Nobel Prize-winning physicist opining on economics does not make their economic views authoritative. Legitimate appeals to authority cite experts within their field of expertise.

Appeal to emotion substitutes emotional manipulation for evidence. 'Think of the children' is a classic appeal to emotion that can be used to support virtually any policy regardless of whether it would actually help children. Emotion can legitimately motivate action, but it is not evidence that a specific policy will achieve its stated goals.

Worked Example: Catching a Straw Man

Straw man is slippery because it feels like a fair rebuttal. Walk through a real exchange:

Advocate: 'We should raise the federal minimum wage to $12 an hour over three years.' Critic: 'My opponent thinks the government should set everyone's salary. That is central planning, and it has failed everywhere it was tried.'

Step 1 — State the original position precisely. A phased rise of one wage floor to $12.

Step 2 — State what the critic attacked. Government setting everyone's salary — full central planning.

Step 3 — Compare. The critic swapped a narrow, specific proposal for a sweeping, extreme one that is easier to knock down. That substitution is the straw man.

Step 4 — Restore and respond fairly. A legitimate reply addresses the actual claim: 'A $12 floor could raise costs for small employers or reduce entry-level hiring — what does the evidence show about job losses at that level?'

Compare these relevance fallacies by what they swap in:

The fix is always the same: pin down the real claim and demand evidence about that.