Finally tossing the old sig, as have had no ID whackjobs to torment with it for a while.
Argumentum ad Ignorantiam:
Fallacy of taking a statement not provably false and implying that it is therefore true
Theists Argument for the Existence of God
There is no evidence against p.
Atheists Argument for the Non-Existence of God
There is no evidence for p.
The whole goal of the culture of science is to use evidence and induction to find the right answer, not to use scientifically useless deductive logic to get into "Nuh-uh!" style pissing contests with people who already "know" the answer.
ad Ignorantiam is one of the more appalling fallacies you see thrown around in the world, because it is assertion based on zero evidence. It's almost always an emotional appeal made to play to the prejudices of the listeners.
So don't fall into the trap; conclusions made with no evidence are worthless.