petitio principii

(also known as: assuming the initial point, assuming the answer, chicken and the egg argument, circulus in probando)

Description: Any form of argument where the conclusion is assumed in one of the premises. Many people use the phrase “begging the question” incorrectly when they use it to mean, “prompts one to ask the question”. That is NOT the correct usage. Begging the question is a form of circular reasoning.

Logical Form:

Claim X assumes X is true.

Therefore, claim X is true.

Example #1:

Paranormal activity is real because I have experienced what can only be described as paranormal activity.

Explanation: The claim, “paranormal activity is real” is supported by the premise, “I have experienced what can only be described as paranormal activity.” The premise presupposes, or assumes, that the claim, “paranormal activity is real” is already true.

Example #2:

The reason everyone wants the new "Slap Me Silly Elmo" doll is because this is the hottest toy of the season!

Explanation: Everyone wanting the toy is the same thing as it being "hot," so the reason given is no reason at all—it is simply rewording the claim and trying to pass it off as support for the claim.

Exception: Some assumptions that are universally accepted could pass as not being fallacious.

People like to eat because we are biologically influenced to eat.