[Reincarnate]

That doesn't prove anything -- it's a warped type of logic (modal logic) that says "a truth is something that is possible." Obviously some things are always "possible," but when you invoke a logic system that rests upon screwed up axioms like that, you can literally prove anything to be true as long as it's not contradictory.

The whole thing goes out the window anyway because I could easily use that logic to say "If it's possible for a God to exist, God exists" and "If it is possible for a Flying Spaghetti Monster to exist but only if there is no God, the Flying Spaghetti Monster exists." I can logically posit either one of these as "true/possible" and yet at the same time I can't have both be true because they contradict. It's all a bunch of silly BS.