We are the only life form of the univers. Not even the only intelligent, but the only one. My arguments are:
Life is absolutely everywhere on earth. There is not a single isolated island or deep trench in the ocean that is not covered by life. If life can live elsewhere, univers would be covered by life. Some bacteria would have been ejected into space by some cataclysme and had colinized nearby planets. Kind of Fermi’s paradoxes.
Antropic argument. Our universe is suitable for life because if it weren’t, we simply wouldn’t be there. Add it to Okam razor. If a smaller, simpler, universe could handle life, we would be in that one. Not our current one.
“Our universe is so huge, so there must be other life form” is not the right statement. Our universe is so huge because it is the smallest universe where life could potentially appear.
Only my opinion, not a scientific demonstration.
And even if the number of worlds would be just 1000, the chance for another kind of life evolving out of the same “thin air” as we did, given millions of years of time, is still pretty high I’d argue. And the number is surely higher than 1000 :-)
Yes, it’s probably not infinite, as far as we “know” (or deducted). But it’s very close to that given how our monkey-brains struggle with incredible big numbers. Many people already struggle to grasp what a billion, let alone a trillion moneyz is. We’re talking of an enourmous number of worlds, with an even more enourmous number of possibilities to form life over the count of millions of years.
Also it would be really really sad, if THIS <points to our species> is the best this universe could come up with. Doesn’t mean I wouldn’t accept the fact if evidence pointed towards it.