This is what alien life will be like. We will decide it is alive but not understand fully what that means.
I don't understand fully what this comment means.
If alien life has DNA (chemistry) like ours, we learn that life as we know it either started somewhere and spread or was re-invented.
If it doesn't, but is obviously alive (move on its own will, hunts, i dont know) we learn that life can exist with different chemistries.
If it's not obviously alive but we determine anyway, whichever way we do that, we've learned of a new aspect of life.
what does "what that means" mean ? ? ?
Are there many varieties of self-replicating molecules? (which I understand is needed to start life) Maaaaybe there's only so many ways that this can get started and RNA is the "only" way to do it. In a similar way that we have a hard time imagining non-carbon life since no other element behaves in the ways that carbon does