slothful induction (i.e., ignoring the evidence).
Slothful induction is the fallacy whereby an inductive argument is denied its proper conclusion, despite strong evidence for inference. Explain? Sure.
One either willfully or through stupidity, refuses to accept what is most likely true based on the evidence presented. Interesting that the name of this logical fallacy gives the benefit of the doubt to the denier as being simply “slothful” or lazy. More often than not, the denier of evidence is not lazy, but rather simply doesn’t like the direction the evidence is heading. I sometimes call this the “sticking your head in the sand” defense.
A great essay of the slothful induction can be found at The Illogic Primer, but here is a key phrase that caught my attention, “Usually it (slothful induction) is a red flag that someone is not principally interested in the truth of a matter. And, because inductive arguments are at best probabilistic, not definitive, someone can always hold out against the preponderance of evidence.”
So once you have found yourself in a debate where the evidence is being ignored, what is the proof? About all you can do is point out that the evidence is being ignored and give your opponent an opportunity to either offer counter evidence, concede the argument, or you just simply end the argument because your opponent is willfully ignoring reason.