"This [absence of evidence] would make a good essay question for an advanced philosophy class. . . ."

Actually, it already is discussed in philosophy classes, because it is an established principle of logic (at the University of Washington, it comes up first in Philosophy 115 [Basic Logic], a freshman level course), and it does appear on exams, usually as an essay question.

If a person makes an assertion, that person is required to provide the proof—to supply the evidence for the assertion. If someone disagrees and the person making the assertion tries to claim it is true "because you can't prove it is not true," he or she is guilty of the Fallacy of Relevance, specifically the

Appeal to Ignorance (Proving a Negative):   an argument that asserts a claim is true because no one can prove it is wrong; this shifts the burden of proof to the audience or opponent rather than the claimant.

Example:   I assert that "there is an invisible gremlin in this room." You say, "The hell, you say! Prove it!" and I say "You prove there isn't!" Fallacy. You can write me off as spouting, literally, nonsense.

This is also discussed quite extensively in law classes, specifically in regard to rules of evidence. Our system of jurisprudence is based on this principle. If you are accused of a crime, it is up to the accuser to prove that the accusation is true. You are assumed to be innocent until proven guilty.

It would be nice if those who want to engage in rational debate would print this off, then read it and heed it:

THIMK!!
But I dream forlorn dreams. That would be far too much to hope for.

Don Firth