>>9936175We actually do have some. We know what's required for life (as we know it), we know under what circumstances RNA reproduces, and we've created various abiogenesis experiments that have potential in that direction.
There's countless planets in the universe under similar conditions, and perhaps even under identical ones, and plenty with the potential to have been under those conditions for longer.
And we have some idea of how ludicrously large the universe is.
I mean, if we were orbiting a quadruple set of neutron stars locked in place by opposing black holes, or some other crazy shit that would render this system in any other way unusual and we were made of anti-matter, then we might be able to say with some confidence that the odds are good we're the only life in the universe - but we're not. This system is typical and we're made up of the most common elements in the universe. If this painfully typical system can create life, there should be countless others that have done the same. Indeed, there's a good chance there's life elsewhere in this system, given we find nucleotides in meteorites all the time.
Intelligent life and civilization, on the other hand, we're less certain of (in the case of the latter, partly due to controversy). Increasingly that's looking more like a series of rare flukes built upon rare flukes that came together in just the perfect fashion. It could very well be that microbial life is common, but complex and intelligent life is maybe found once in a million galaxies. (Granted, that'd still mean there's a lot of it out there - but odds are, we'd never meet it.)
