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That is a good point. I agree with you. And people do have suggestions as to how life can be more probable than naively expected. But this answers the question

by gpsx 12y ago

That is a good point. I agree with you. And people do have suggestions as to how life can be more probable than naively expected. But this answers the question why there is life at all as opposed to why we don't see more of it. My bias is that life is highly improbable and that we will not find any other life in our universe. But I also think it is no miracle that we exist, as I will describe. Given that I am trying to say this in one paragraph, it may not sound well justified, but it is how I view the problem. I'll start with Schrodinger's cat. A cat is in a box with some radioactive source that can decay and kill the cat. You can ask if the cat is alive or dead - and the answer is both. I will ignore the next part (Schrodinger's whole point) about what happens when the human observes it. There are different interpretations about why the human thinks the cat is definitely in one of the two states as opposed to both. This has to do with the human's observation and is not important for now. The point is that the cat is in both states. The universe can be in multiple states, some with life on earth and some without. Every possible state that can exist, does. So no matter how improbable we are, we will exist in some version of the universe. And there would be lots of other life too, just maybe not in our version of the universe. So the probability of life existing doesn't impact whether or not we should exist, but it does impact whether or not we see other life. I don't think we will. But as correctly pointed out, we don't know the answer to this right now.

conesus 12y ago
The universe may / be as great as they say / but it wouldn't be missed / if it didn't exist. - Piet Hein
jacquesm 12y ago
> My bias is that life is highly improbable and that we will not find any other life in our universe. It's probable enough for you to be writing this. The only options are 0, one and many. We can rule out '0'. That leaves us to decide whether the chances of us being the only one are larger than the chances that we are one of many. Obviously the second one has more chance of being true the one where there is only one. But we like to consider ourselves to be special so most people will believe the 'one'. Just like the sun used to revolve around the earth, now we're essentially seeing the universe as revolving around us. The alternative, that we're not special is not compatible with a lot of our collective culture.
- gpsx 12y ago
  The point is that there are multiple universes, according to the quantum mechanics interpretation I subscribe to. So all of your options are true: 0, 1 and many. My position, which is admittedly no better than a guess, is that most universes by a far majority have 0. By virtue of me writing this, among other things, we live in a universe with at least 1. Again, my position would be that it is unlikely we have more than 1 in our universe. What you are saying it true under the assumption there is a single universe.
  - darkmighty 12y ago
    I think you're trying to articulate is the Anthropic principle [1]. It basically states that the probability that "some" life exists is 1. I'm not sure what the name of this next one is, but I believe it's a widely defended scientific principle that we're "typical" in some sense. This principle gets hard to justify cosmologically (it reduces to Occam's Razor locally), but it makes sense to me. It rejects very clearly some quirks like the Bolztmann Brain [2] argument. [1] http://en.wikipedia.org/wiki/Anthropic_principle http://en.wikipedia.org/wiki/Anthropic_principle [2] http://en.wikipedia.org/wiki/Boltzmann_brain http://en.wikipedia.org/wiki/Boltzmann_brain
- jawns 12y ago
  > Obviously the second one has more chance of being true the one where there is only one. That is not at all obvious to me. You are essentially taking the odds of the odds of something. A statistician can correct me, but I don't think it works the same way as calculating the odds of something. Like, it's not as if we have a roulette wheel where "1/10^24" is an option, "2/10^24" is an option, "3/10^24" is an option, etc. In that case, "many" outweighs "1," certainly. But if the odds of abiogenesis are so unlikely that we happen to be the only life in the universe, it doesn't seem like those odds must necessarily be wrong simply because it's logically possible for them to be more or less likely than they are. But even then, it's kind of a wash. For as much as it could be logically possible for the odds to be more likely than they are (which would allow abiogenesis to occur more frequently), it would also be logically possible for the odds to be less likely than they are.
_greim_ 12y ago
The WAP accounts for high improbability by positing a multiverse, but (at least as I understand it) it doesn't predict high improbability, even if there is a multiverse. Also, in a multiverse scenario, the improbable thing might not be the formation of life, but the fine-tuning of the laws of physics which allows the formation of life. In which case life might be relatively common.
- danieltillett 12y ago
  Also, in a multiverse scenario, the improbable thing might not be the formation of life, but the fine-tuning of the laws of physics which allows the formation of life. In which case life might be relatively common. If we assume that this tuning is not an all or nothing event then the larger the possible universe size the more likely it is that we lie within an region where the features are tuned just enough to let one intelligent life form arise. You can think of the tuned conditions that allow life to be common to be a bullseye that is surrounded by tunings that are close enough to allow life to occur infrequently. If you were to pick a region at random out of the regions that contain intelligent life then it is likely that you would pick one of the surrounding regions not the bullseye. This is also an explanation for Fermi's paradox.
  - dTal 12y ago
    You must factor in that such a region would contain a low percentage of the total number of civilizations intelligent enough to consider the question. A well-tuned universe would be teeming with life - it is therefore more likely that we find ourselves in such a universe (which was the point of the GP). You can think of it, not as a bullseye, but as a gaussian spot. It strikes me that the issue at play here is how one chooses to "sample" the anthropic principle, for want of a better term. When you say "pick a region at random", you assume a uniform probability distribution over the set of all universes supporting life (which incidentally is not possible if the number is infinite). But you don't say how to resolve the probabilities with universes containing multiple intelligent life forms - you do select randomly among those too? If so, shouldn't you rather be picking "randomly" from the set of all intelligent life forms in all universes in the first place?
sgt101 12y ago
This is one explanation, but for me fails two tests. The first (pointed out below) is that it is heliocentric - it's about us. The second is that it avoids freedom of will and consciousness in the sense of self perception. It assumes that I am a zombie, and I deny that. I concede that others may be zombies, although I think that they aren't. My actions either navigate me from state to state or create new states. Physics does not account for this; physics is incomplete. I'll leave occams razor on the shaving table, as it's a heuristic and I don't like it for logic - but infinite infinities fails occams too.
- tomp 12y ago
  What does "freedom of will" mean to you? What you describe (actions move you from state to state) sounds like determinism to me.
  - sgt101 12y ago
    To decide which state to move to. That I (and others) are agents that change the future of the universe by choice within the frameworks of possibility.

by gpsx 12y ago

conesus 12y ago

The universe may / be as great as they say / but it wouldn't be missed / if it didn't exist. - Piet Hein

jacquesm 12y ago

> My bias is that life is highly improbable and that we will not find any other life in our universe. It's probable enough for you to be writing this. The only options are 0, one and many. We can rule out '0'. That leaves us to decide whether the chances of us being the only one are larger than the chances that we are one of many. Obviously the second one has more chance of being true the one where there is only one. But we like to consider ourselves to be special so most people will believe the 'one'. Just like the sun used to revolve around the earth, now we're essentially seeing the universe as revolving around us. The alternative, that we're not special is not compatible with a lot of our collective culture.

gpsx 12y ago
The point is that there are multiple universes, according to the quantum mechanics interpretation I subscribe to. So all of your options are true: 0, 1 and many. My position, which is admittedly no better than a guess, is that most universes by a far majority have 0. By virtue of me writing this, among other things, we live in a universe with at least 1. Again, my position would be that it is unlikely we have more than 1 in our universe. What you are saying it true under the assumption there is a single universe.
- darkmighty 12y ago
  I think you're trying to articulate is the Anthropic principle [1]. It basically states that the probability that "some" life exists is 1. I'm not sure what the name of this next one is, but I believe it's a widely defended scientific principle that we're "typical" in some sense. This principle gets hard to justify cosmologically (it reduces to Occam's Razor locally), but it makes sense to me. It rejects very clearly some quirks like the Bolztmann Brain [2] argument. [1] http://en.wikipedia.org/wiki/Anthropic_principle http://en.wikipedia.org/wiki/Anthropic_principle [2] http://en.wikipedia.org/wiki/Boltzmann_brain http://en.wikipedia.org/wiki/Boltzmann_brain
jawns 12y ago
> Obviously the second one has more chance of being true the one where there is only one. That is not at all obvious to me. You are essentially taking the odds of the odds of something. A statistician can correct me, but I don't think it works the same way as calculating the odds of something. Like, it's not as if we have a roulette wheel where "1/10^24" is an option, "2/10^24" is an option, "3/10^24" is an option, etc. In that case, "many" outweighs "1," certainly. But if the odds of abiogenesis are so unlikely that we happen to be the only life in the universe, it doesn't seem like those odds must necessarily be wrong simply because it's logically possible for them to be more or less likely than they are. But even then, it's kind of a wash. For as much as it could be logically possible for the odds to be more likely than they are (which would allow abiogenesis to occur more frequently), it would also be logically possible for the odds to be less likely than they are.

_greim_ 12y ago

The WAP accounts for high improbability by positing a multiverse, but (at least as I understand it) it doesn't predict high improbability, even if there is a multiverse. Also, in a multiverse scenario, the improbable thing might not be the formation of life, but the fine-tuning of the laws of physics which allows the formation of life. In which case life might be relatively common.

danieltillett 12y ago
Also, in a multiverse scenario, the improbable thing might not be the formation of life, but the fine-tuning of the laws of physics which allows the formation of life. In which case life might be relatively common. If we assume that this tuning is not an all or nothing event then the larger the possible universe size the more likely it is that we lie within an region where the features are tuned just enough to let one intelligent life form arise. You can think of the tuned conditions that allow life to be common to be a bullseye that is surrounded by tunings that are close enough to allow life to occur infrequently. If you were to pick a region at random out of the regions that contain intelligent life then it is likely that you would pick one of the surrounding regions not the bullseye. This is also an explanation for Fermi's paradox.
- dTal 12y ago
  You must factor in that such a region would contain a low percentage of the total number of civilizations intelligent enough to consider the question. A well-tuned universe would be teeming with life - it is therefore more likely that we find ourselves in such a universe (which was the point of the GP). You can think of it, not as a bullseye, but as a gaussian spot. It strikes me that the issue at play here is how one chooses to "sample" the anthropic principle, for want of a better term. When you say "pick a region at random", you assume a uniform probability distribution over the set of all universes supporting life (which incidentally is not possible if the number is infinite). But you don't say how to resolve the probabilities with universes containing multiple intelligent life forms - you do select randomly among those too? If so, shouldn't you rather be picking "randomly" from the set of all intelligent life forms in all universes in the first place?

sgt101 12y ago

This is one explanation, but for me fails two tests. The first (pointed out below) is that it is heliocentric - it's about us. The second is that it avoids freedom of will and consciousness in the sense of self perception. It assumes that I am a zombie, and I deny that. I concede that others may be zombies, although I think that they aren't. My actions either navigate me from state to state or create new states. Physics does not account for this; physics is incomplete. I'll leave occams razor on the shaving table, as it's a heuristic and I don't like it for logic - but infinite infinities fails occams too.

tomp 12y ago
What does "freedom of will" mean to you? What you describe (actions move you from state to state) sounds like determinism to me.
- sgt101 12y ago
  To decide which state to move to. That I (and others) are agents that change the future of the universe by choice within the frameworks of possibility.