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We can't know that life is guaranteed unless we find another example of life arising independently. We don't know how many random chemical reactions are requir
by DennisP 3y ago
We can't know that life is guaranteed unless we find another example of life arising independently.
We don't know how many random chemical reactions are required for life to be likely. We probably agree that a small puddle isn't likely to spontaneously generate life within a century. We like to think that one planet for a billion years is about the right size. But it could be that it takes a whole universe of planets before it's likely to happen once.
If that were the case, then the universe would look exactly like it does now, with us living on the planet where it happened and no life discovered elsewhere so far.
- bmitc 3y ago> We can't know that life is guaranteed unless we find another example of life arising independently. Of course not. But that's why we discuss probabilities. We also can't discuss definitively about things that we have no reasonable ways to detect. So claims about there's no life because we would have seen them is completely worthless given that we have very, very few, if any, ways to detect such life. Assuming it existed, are we even able to detect a planet like Earth with similar animal and human activity in any other solar system, even in the Milky Way? I am personally not aware of such general capability.
- DennisP 3y agoYes, but we have no idea what the probabilities are. We have no basis for saying "it is probable that Mars had life." If we found native life on Europa or something, that would change things completely. Independent life arising at least twice in the same solar system would make it clear that life is common. But a sample size of one, with the anthropic principle, leaves us no clue. Life might be common, or we might be unique.