Proof by assertion
Also called: Ipse dixit, Repeating the claim
Repeating a claim, more firmly each time, instead of supporting it.
How to spot it
Has the claim been said three times but never argued?
Example
“It's true. It's simply true. I don't know how many times I have to say it.”
How to answer it
Ask for one reason that doesn't repeat the claim.
Related
- Begging the question: Using the conclusion as one of the reasons for the conclusion.
- Appeal to common sense: Treating something as obvious so it doesn't need an argument.