To one who has faith, no explanation is necessary.

I'm going to disagree a bit here. I'd say wishful thinking comes from a desire for something to be true, but faith comes from a more pragmatic need to believe things are true in order to act. The human brain doesn't have infinite resources to keep track of all spectrums of possibilities and probabilities, so we make assumptions about all kinds of things and consider them true to conserve brain power, and that ends up including assuming things for which we have little evidence. Of course, that makes it easier for wishful thinking to turn into faith, but I do think the two are different.