Denying the Antecedent

This is a heavily used fallacy throughout online arguments.

Denying the Antecedent
Photo by 愚木混株 cdd20 / Unsplash

The fallacy:

  • If A, then B
  • Not B, therefore not A

The reality:

  • If A, then B
  • Not B does NOT imply not A.

Example from Nassim Nicholas Taleb's tweet:

Nassim's Tweet

Let me elaborate on this, Fat Tony is a character created by Nassim to impersonate the characteristics of Street Smarts.

Tests don't measure skill very well. So getting As on tests doesn't measure street smarts.

But that does not mean it disqualifies it.

Don't confuse getting As with not being street smart.


Logical Fallacy: Denying the Antecedent