Faith?

[Eilonnwy]

Arcanus, by your reasoning we cannot say pink unicorns don't exist.

If you dismiss a claim because of ignorance of the evidence, yes you're are committing the fallacy. But it's far different if you search for evidence where there should be and find nothing. You can't hold everything as true or possible just because solid evidence for it's non-existence isn't there. There is that whole saying that absence of evidence does not equal evidence of absence. I believe that's generally true with one huge caveat. If you search for evidence where there most certainly should be evidence, based on your claim, and then don't find any, I think you're justified in saying something doesn't exist, as Sagan explained in his Dragon analogy. Of course, you would be committing the fallacy if evidence did come around and you ignored it. A true skeptic is willing to reconsider when better evidence comes along.

It's a fine line, I agree, but a line nonetheless.