As much as I disagree with Quag when it comes to religious views, he's spot on about this "usage of logic" debate though... "could be possible" and "possible" are two different things... the first quote is for when you haven't yet established that something is possible, you haven't seen it happen yet, so from a purely logical standpoint, you don't truly know either way... it could be possible, but it could also be impossible, you just don't know because you haven't seen it happen... the second quote is for when you have now seen it happen at least one time, so you can now logically establish that something is definitely not impossible because it in fact did happen at least once...
Maybe I didn't describe it in a very good way, but that's my attempt at making it clearer... Quag can correct me if I'm agreeing with him in an illogical way