[derbOac]

I had a related thought which is that there's some bistability involved maybe. That is, even if there's not hard boundaries and exceptions can be found to any rule, in aggregate systems tend to behave as one or the other roughly speaking.

Another problem is our sample size is relatively small — it seems difficult to come to a definition of life when we don't know if it exists elsewhere in the universe, and if so, what that looks like. In some ways asking "how would we know we've found life elsewhere" might be the most useful approach. But we have no way to confirm or confirm our expectations at this point.