The Ad Hominem Fallacy

Misconception vs. Truth

Misconception:
If you can’t trust someone, you should ignore that person’s claims.

Truth:
What someone says and why they say it should be judged separately.

The Ad Hominem Fallacy Defined

  • Ad Hominem: Latin for “to the person,” this fallacy occurs when you attack the person making an argument instead of the argument itself.
  • Character Attacks: Dismissing someone’s claims based on character or personal history rather than on the merits of their argument.

Examples of Ad Hominem Fallacy

  • Courtroom: Discrediting a defendant because of past crimes or lies, rather than evaluating the evidence presented.
  • Science and Journalism: Assuming all work by a scientist or journalist is invalid after an unethical act, rather than examining each piece of work individually.
  • Personal Attacks: Responding to criticism by attacking the critic’s character (e.g., dismissing driving advice from a self-proclaimed "worst driver").

Guilt by Association

  • Political Ads: Using associations with disliked groups or individuals to discredit a politician, irrespective of the actual argument.
  • Fallacy in Reverse: Trusting someone’s claim based on their respectable job or appearance, without evaluating the evidence.

Practical Implications

  • Judging Character vs. Truth: Differentiating between trustworthiness and the validity of the argument is crucial.
  • Evidence Over Character: Making decisions based on evidence rather than personal impressions or past behavior of the individual.

Inverse Ad Hominem Example

  • Reverse Fallacy: Assuming someone is credible because of their status, while ignoring evidence against them, like the case of an astronaut in a criminal trial.

Psychological Basis

  • Character Consistency: Humans naturally look for consistent behaviors in people to judge trustworthiness, a useful evolutionary trait that can override logic.

Avoiding the Fallacy

  • Assess arguments based on evidence and logic, not the personal traits or past of the individual presenting the argument.