I Don't Believe It!

Dene Bebbington presents a couple of bad but popular arguments.

- Dene Bebbington

How often have you read or heard someone say something like “That’s not possible, it couldn’t have happened like that”? That person may think it’s a clever rebuttal which stops debate in its tracks and gives them the rhetorical victory, but it’s a fallacy in informal logic known as the argument from personal incredulity.

Humans have a need for certainty – we have a psychological preference against doubt – which is why this fallacy has a particular allure. To understand what’s going on when someone has committed this fallacy, we can unpack its unstated logic:

1. I can’t imagine how this thing could be true

2. But if this thing is true then I should be able to imagine how it’s true

3. Therefore this thing is not true

Once the premises of the argument, 1 and 2, are laid bare, its flaw is exposed. The premise that ‘If this thing is true then I should be able to imagine how it’s true’ is evidently false, or at least, is not necessarily true.