Not sure how it would? Us being the only life doesn't really negate arguments for evolution and whatnot, does it?
Though, regardless of what we discover... both sides will take all new evidence as proof they're right... it's not like either can be proven wrong anyway.
Jesus Chris him(xer?)self could appear in Indianapolis, and people would just discount them as a homeless man on drugs. Alternatively, an entire civilization could be found a galaxy away, and people would say it's part of his plan or something,
You are of course, correct. Just like, for me, the existence of ET doesn't change my view of God, it is a reasonable position for the non-religious to say it doesn't change their view. It just mean that math worked out in our favor.
But, as Kut alludes to, I think there's a deeper meaning. If humanity is the evolutionary pinnacle within the universe, the there's the intelligent design issue. Or, to me, the related position that our existence is a mathematical miracle. Something that shouldn't have happened, but did.
Moreover, it could lend credence to the Genesis passage that grants humans dominion over everything. We would have that. We could go forth and multiply across the universe (assuming inhabitable planets exist and we had the technology to get there).
Funny thing is, we have no clue what the chances are of life or intelligent life developing. If there was other intelligent life, how would we ever know? We wouldn't be able to tell if there was something on the other side of our galaxy, let alone in any of the untold number of galaxies in the Universe.
Yeah, that's something that the stats people try to take into account.
For practical purposes, I think it makes sense to limit the inquiry to "now." It doesn't matter if there was an intelligent life form in alpha centauri 100,000 years ago, but died out in an extinction event.