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The numbers involved here make the chances that we are unique vanishingly small IMO; the numbers are the justification. Those numbers mean that even if the odd

The numbers involved here make the chances that we are unique vanishingly small IMO; the numbers are the justification. Those numbers mean that even if the odds of life are vanishingly small, there was and will be other life out there. We’re not talking about one world like Earth but likely billions at least. As far as we can tell our star is in no way unique or special, and if those same processes happened say 100000000000000000000000 times elsewhere, it seems very unlikely to me that they wouldn’t produce self-replicating life as well somewhere, sometime.

pfdietz 2y ago
> The numbers involved here make the chances that we are unique vanishingly small IMO; the numbers are the justification. This is nothing but handwaving. Your argument evaporates when examined closely or critically. > Those numbers mean that even if the odds of life are vanishingly small, there was and will be other life out there. Obviously not. If there are N places where life could arise, but the chance that life arises at each is << 1/N, then your conclusion does not obtain. For any N, there is always a sufficiently small chance life would arise that would ruin your conclusion. You are slipping in an assumption again, that the chance can't be "too small". But we can't rule out that some event in OoL is extremely, astronomically, exponentially unlikely. All known examples of living systems capable of Darwinian evolution have great complexity, and that initial complexity has to have come from somewhere. We can't rule out that at least some of it was just due to some extremely low probability event(s).
- grey-area 2y ago
  So we have: Unimaginably large no of plants, odds of life are rare, but life is common because of the no of planets. Unimaginably large no of planets, odds of life are such that it only emerged once in billions of years over 10^25 planets, so odds of life emerging are something insane like 10^30:1. Your conclusion that life is probably unique on Earth is possible, but seems highly unlikely, and in the absence of other information, I'm going to assume the most likely outcome, which is that we are not alone, we don't yet know how alone, but the outlier is to say life emerged but once. Feel free to make whatever assumptions you like, but stating the obvious about assumptions doesn't change my argument at all or invalidate it - obviously you have to make assumptions when information is incomplete. Nobody is saying with certainty there is or is not life (clearly we don't yet know), we're talking about the most likely outcome given what we know. We have found the building blocks of life on asteroids already, if we do find extra-terrestrial life in our neighbourhood it would mean life is extremely common in the universe due to the no of planets and time, if not, it doesn't mean much, it just means it is not extremely common, the outcome you posit is way on the other extreme of the scale. https://eos.org/articles/lifes-building-blocks-found-in-bennu-samples https://eos.org/articles/lifes-building-blocks-found-in-benn...
  - pfdietz 2y ago
    > but seems highly unlikely How is this judgment reached? What's the probability distribution assumed for the probability of life arising, and how was that estimated? This is nothing more than a personal feeling on your part dressed up to try to make it seem to be something that isn't completely subjective. This whole subject, touching as it does on existential questions, is rife with opportunities for bias, so it's very important to be rigorous and explicit in reasoning, not resort to "feelings", or in arguments that end being exercises in rationalization of those feelings. What one must do in such a situation is seriously question ones own assertions. "How do I know that this is true?" "What would look different if this weren't true?" So many seem to just voice their intuition and stop thinking. I want you to imagine an alternative world, let's call it Schmearth. It's inhabited by Schmumans, orbited by the Schmoon. It's in a universe much like ours, but the laws of physics are such that OoL has a very difficult step, so Schmearth is the only life bearing planet in their universe. My question to you: what would be different that they would see that we do not (or vice versa)? If you can't identify such a thing, how do we know we aren't ourselves living on Schmearth?

pfdietz 2y ago

> The numbers involved here make the chances that we are unique vanishingly small IMO; the numbers are the justification. This is nothing but handwaving. Your argument evaporates when examined closely or critically. > Those numbers mean that even if the odds of life are vanishingly small, there was and will be other life out there. Obviously not. If there are N places where life could arise, but the chance that life arises at each is << 1/N, then your conclusion does not obtain. For any N, there is always a sufficiently small chance life would arise that would ruin your conclusion. You are slipping in an assumption again, that the chance can't be "too small". But we can't rule out that some event in OoL is extremely, astronomically, exponentially unlikely. All known examples of living systems capable of Darwinian evolution have great complexity, and that initial complexity has to have come from somewhere. We can't rule out that at least some of it was just due to some extremely low probability event(s).

grey-area 2y ago
So we have: Unimaginably large no of plants, odds of life are rare, but life is common because of the no of planets. Unimaginably large no of planets, odds of life are such that it only emerged once in billions of years over 10^25 planets, so odds of life emerging are something insane like 10^30:1. Your conclusion that life is probably unique on Earth is possible, but seems highly unlikely, and in the absence of other information, I'm going to assume the most likely outcome, which is that we are not alone, we don't yet know how alone, but the outlier is to say life emerged but once. Feel free to make whatever assumptions you like, but stating the obvious about assumptions doesn't change my argument at all or invalidate it - obviously you have to make assumptions when information is incomplete. Nobody is saying with certainty there is or is not life (clearly we don't yet know), we're talking about the most likely outcome given what we know. We have found the building blocks of life on asteroids already, if we do find extra-terrestrial life in our neighbourhood it would mean life is extremely common in the universe due to the no of planets and time, if not, it doesn't mean much, it just means it is not extremely common, the outcome you posit is way on the other extreme of the scale. https://eos.org/articles/lifes-building-blocks-found-in-bennu-samples https://eos.org/articles/lifes-building-blocks-found-in-benn...
- pfdietz 2y ago
  > but seems highly unlikely How is this judgment reached? What's the probability distribution assumed for the probability of life arising, and how was that estimated? This is nothing more than a personal feeling on your part dressed up to try to make it seem to be something that isn't completely subjective. This whole subject, touching as it does on existential questions, is rife with opportunities for bias, so it's very important to be rigorous and explicit in reasoning, not resort to "feelings", or in arguments that end being exercises in rationalization of those feelings. What one must do in such a situation is seriously question ones own assertions. "How do I know that this is true?" "What would look different if this weren't true?" So many seem to just voice their intuition and stop thinking. I want you to imagine an alternative world, let's call it Schmearth. It's inhabited by Schmumans, orbited by the Schmoon. It's in a universe much like ours, but the laws of physics are such that OoL has a very difficult step, so Schmearth is the only life bearing planet in their universe. My question to you: what would be different that they would see that we do not (or vice versa)? If you can't identify such a thing, how do we know we aren't ourselves living on Schmearth?