Salon has an interesting article reposted from Scientific American on whether or not we’ll ever find intelligent extraterrestrial life. It actually gives what seems like a reasonable argument, which is surprising given the amount of pseudoscience attached to anything involving aliens.
Unfortunately, the author’s view is not very satisfying. A few decades from now it’s likely that we won’t know any more than we do now. We can now find other planets, but even if they have intelligent life there’s no guarantee that we’ll ever find it. We don’t even have a good way to estimate how likely it is that such life exists or whether we’ll find it assuming it exists at all. Whether or not intelligent life outside Earth exists will probably remain a philosophical question for the foreseeable future.