Answer:
Appeal to ignorance
Step-by-step explanation:
A logical fallacy is an error in reasoning that tries to prove a point or give reason to a theory or thought that is wrong from the beginning because the logical fallacy does not provide justification, in this case the logical fallacy is the appeal to ignorance which basically is saying I'm right, because there's no proof against my process of thought, just because there's no proof that Atlantis existed I can not assure that it never existed.