Basically SIA and SSA are seen as very different. But some problems that we would feel instinctively should illustrate their differences—situations with varying numbers of agents like above—do not.
One obvious point is that if this is correct then in our universe one can probably safely reason with SIA and SSA and get similar results. This means that if there’s something that goes wrong with applying anthropic reasoning in some contexts it probably isn’t lack of precision in the anthropic principles being applied.
Assuming MWI is correct, the probability of intelligent life in this universe is 100%. If we assume it’s false, and that the universe is of finite size, and that it’s only about as much as we can see, it still holds an absurd number of galaxies. It’s far from obvious how common life is. All we know is that it looks like there isn’t any more in this one galaxy.
Besides that, the only major reasoning I’ve seen with either of those is the Doomsday Argument, which falls under that exception you mentioned. It’s largely about our ancestors and descendants.
Assuming MWI is correct, the probability of intelligent life in this universe is 100%
The probability of intelligent life in this universe is 100% conditioned on the fact that we are intelligent, and barring the fact that some powers would likely challenge this proposition.
Assuming MWI is correct, and that by Universe you mean the larger, seemingly infinite structure our Hubble Volume is embedded in, then yes, the probability of intelligent life (other than us) is unity. Though we are still alone if they are over the Hubble Horizon.
If by Universe you mean “our” observable universe, then MWI seems to guarantee that some (possibly small) proportion of branches of this Hubble volume will have no intelligent observers other than us. Still other branches/histories of “our” Hubble volume should have no observers at all.
Is there a point to this?
Basically SIA and SSA are seen as very different. But some problems that we would feel instinctively should illustrate their differences—situations with varying numbers of agents like above—do not.
One obvious point is that if this is correct then in our universe one can probably safely reason with SIA and SSA and get similar results. This means that if there’s something that goes wrong with applying anthropic reasoning in some contexts it probably isn’t lack of precision in the anthropic principles being applied.
For certain types of models.
Assuming MWI is correct, the probability of intelligent life in this universe is 100%. If we assume it’s false, and that the universe is of finite size, and that it’s only about as much as we can see, it still holds an absurd number of galaxies. It’s far from obvious how common life is. All we know is that it looks like there isn’t any more in this one galaxy.
Besides that, the only major reasoning I’ve seen with either of those is the Doomsday Argument, which falls under that exception you mentioned. It’s largely about our ancestors and descendants.
The probability of intelligent life in this universe is 100% conditioned on the fact that we are intelligent, and barring the fact that some powers would likely challenge this proposition.
Assuming MWI is correct, and that by Universe you mean the larger, seemingly infinite structure our Hubble Volume is embedded in, then yes, the probability of intelligent life (other than us) is unity. Though we are still alone if they are over the Hubble Horizon.
If by Universe you mean “our” observable universe, then MWI seems to guarantee that some (possibly small) proportion of branches of this Hubble volume will have no intelligent observers other than us. Still other branches/histories of “our” Hubble volume should have no observers at all.
Right. Now I feel stupid for missing that.
Different objection: the amount of life isn’t a poisson distribution. It has much thicker tails, as the absurd amount of life in MWI shows.