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.
The closer the universe is to being infinite, the more likely ANYTHING that is possible, will happen. Like life, in whichever form.
It might not be technically infinite, but so incredibly gargantuanly vast, that to us finite Lil meatsacks, it basically is.
Even if the chance for developing life might be infinitesimal, there are a real lots of dice-rolls in that universe, so why should it be only us...
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