Comment Re:What difference would it make if we were "it"? (Score 2) 334
This is the crux of the "intelligent life out there" argument. We literally have no idea how probable intelligent, industrialized life is to develop - even on planets proven to have life and what time scale or necessary events must take place for it to arise. Apes likely became intelligent on Earth because of extreme changes in habitats and multiple near-extinction events which forced survivors to adapt and adopt tool use to compete and thrive. Maybe such evolutionary pressures are rare, and maybe species that endure them find other survival methods or simply go extinct. Animals only need to be "smart enough" to survive and breed. It may take extraordinary events to push them into an arms race for intelligence to better control and shape their environment.
I personally think life is common - as its components are common, and many chemical reactions necessary for life can happen with a solvent (water) and energy (sunlight) without life. I think intelligent life capable of spaceflight is exceedingly rare. Dolphins, dinosaurs, parrots, and octopus rarely dreamed of space flight, I think.
Life may exist nearly everywhere that conditions allow - as it likely spontaneously came from natural chemical reactions on Earth (or was seeded from another world where it spontaneously came into being), there's no reason to believe it's not a natural event itself which is likely to occur wherever it can given enough time. To say that such life would evolve into an intelligent, tool-using being capable of interstellar communication or even interplanetary flight is quite another issue entirely.
From an evolutionary perspective, intelligence may be highly overrated.