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No. 271 · Evidence · Fallacy

Ad Hominem

An argument does not become false because you dislike the person making it.

Ad hominem means "to the person". It's the fallacy of dismissing a claim because of who makes it, attacking their character, motives or credentials rather than their reasoning. A claim is true or false based on evidence, not on the speaker.

To guard against it, restate the argument without the person's name and judge it on its own. Treat a speaker's track record as a reason to check more carefully, never as proof they're wrong.

In the Almanac

“Wegener the outsider”, 1912–1960s · “Wirecard”, 2015–2020

Both stories in full, three ways to use it and where it misleads.

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Ad Hominem

Questions

What is Ad Hominem?

Ad hominem means "to the person". It's the fallacy of dismissing a claim because of who makes it, attacking their character, motives or credentials rather than their reasoning. A claim is true or false based on evidence, not on the speaker.

How do you avoid Ad Hominem?

To guard against it, restate the argument without the person's name and judge it on its own. Treat a speaker's track record as a reason to check more carefully, never as proof they're wrong.

When does Ad Hominem matter?

Ad Hominem is one of the 68 mental models for evidence, the situations where you ask: Is this really true? Within that, it belongs to “Spotting a bad argument”, alongside Appeal to Authority, Appeal to Emotion and Appeal to Ignorance.

What is an example of Ad Hominem?

Two stories show it at work: Wegener the outsider (1912–1960s) and Wirecard (2015–2020). Both are told in full in The Mental Models Daily Almanac, which has two stories for each of its 365 models.

Which mental models are related to Ad Hominem?

Strawman Fallacy, Personas and Semmelweis Reflex. Ad Hominem itself comes from fallacy.