This is always assumed as an axiom. It is also wrong. Claims require sufficient evidence to prove them. Period. Labeling a claim as "extraordinary" does not in

This is always assumed as an axiom. It is also wrong. Claims require sufficient evidence to prove them. Period. Labeling a claim as "extraordinary" does not in any way change the standard of proof for said claim. So far, no one has put forward anything even remotely approaching sufficient proof that Phobos is artificial.