Which informal fallacy is committed in the following argument? “Famous actor…

Concept

An appeal to inappropriate authority occurs when a claim is accepted because it is endorsed by a person whose fame or expertise is not relevant to that claim.

The defect concerns the relevance of the cited person's expertise, not merely the use of testimony.

Application

The premise cites an actor's statement about whether astrology is a science. Acting fame supplies no relevant scientific expertise, yet the conclusion asks scientists to accept the claim on that basis.

The reasoning therefore commits an appeal to inappropriate authority.

Contrast with the other fallacies

• A red herring diverts attention by introducing an irrelevant issue; the statement instead relies on a celebrity's testimony.

• A straw man distorts an opponent's position and attacks the distorted version; no position is distorted here.

• An appeal to ignorance treats a claim as true or false because the opposite has not been proved; the statement does not rely on absence of proof.

Cross-check

If the cited person were a suitably qualified expert and the claim fell within that expertise, expert testimony could be relevant. Changing only the speaker's credentials removes the defect, confirming that relevance of authority is the governing test.

Result: Appeal to inappropriate authority.