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Cognitive Biases

Argument from Personal Incredulity

The logical fallacy of concluding that a claim is false because it seems personally unbelievable, including dismissing wrongdoing solely because you trust the person involved.

THE IDEA

Argument from Personal Incredulity

This fallacy occurs when someone argues that a claim cannot be true because they personally find it hard to believe, or because they 'know' the person involved. In the example, Spock testifies it is 'impossible' Captain Kirk is guilty of negligence because Spock knows the captain. This reasoning is fallacious because personal knowledge of character does not negate the possibility of wrongdoing; evidence and facts must be considered. In the story, Kirk was indeed framed. A correct conclusion does not make the reasoning valid.

When to use it

  • In courtrooms where character testimony is overvalued

  • In personal relationships when we refuse to believe a loved one could do something

  • In business when we ignore red flags due to past positive experiences with a colleague

  • In everyday decision-making when we rely on gut feelings rather than data

FROM THEORY TO EVERYDAY LIFE

In practice

01

Star Trek Trial

In a Star Trek scenario, Spock testifies that it is 'impossible' for Captain Kirk to be guilty of negligence because 'I know the captain.' The narrative confirms Kirk was framed, so the conclusion is true, but the reasoning is still a logical fallacy.

02

Everyday Character Defense

A manager claims a trusted employee could not have embezzled funds because 'I've known them for years and they're honest.' This dismisses the accusation without examining the evidence.

✳

A MOMENT TO REFLECT

Put it to work.

  1. Can you recall a time when you dismissed a possibility based on personal knowledge of someone, only to be proven wrong?

  2. How would you evaluate an argument that claims something is impossible because of a person's character?

  3. What distinguishes a valid character reference from a logical fallacy?

Connected ideas

Another lens can bring the same problem into focus.

Often confused with

CONTINUE THE CONVERSATION

Source texts

  • The Scout Mindset (Julia Galef)
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