Appeal to Ignorance (Ad Ignorantiam) is a logical fallacy in which one argues that a proposition is true simply because it has not been proven false, or that it is false because it has not been proven true. It relies on the assumption that the absence of evidence is evidence of absence, which is not necessarily a valid assumption. Essentially, it’s a claim based on the absence of evidence rather than hard evidence itself.
Example: “No one has ever been able to prove that extraterrestrial beings have visited Earth, so they must not exist.”
In this example, the absence of definitive proof about extraterrestrial visits is used as “evidence” that such beings don’t exist. Just because something hasn’t been proven doesn’t mean it’s false, and just because something hasn’t been disproven doesn’t mean it’s true. The truth of a claim should be based on evidence supporting it, not the lack of evidence against it.