In a single universe interpretation, we can posit biogenesis is rare, but we do know it happened at least once in ~two trillion galaxies worth of stars in ~13 billion years.
In MWI it could be even rarer—with unlimited branches for wild coincidences of chemistry to occur, we’re necessarily living in a branch where such did occur.
Allow for argument’s sake that biogenesis is so rare that branches where life is found are tiny in measure. We find ourselves in such a branch, so anthropics and branching kind of gives us the first miracle for free. But given we’re here, the chance it happened here independently TWICE is vanishingly small again.
If biogenesis is so rare it occurs in a tiny minority of branches only, then in almost all branches where it does occur, it only occurs once.
If I haven’t badly misunderstood something, I think if we accept MWI then it seems much more plausible that we are the only life in the universe.
Trying to reason from a single datapoint out of an unknown distribution is always going to be low-information and low-predictive-power. MWI expands the scope of the unknown distribution (or does it? It all adds up to normal, right?), but doesn’t change the underlying unknowns.
In Transparent Newcomb’s Problem, your decision determines whether you existed when you were making the decision. It’s not valid to conclude that you exist merely from subjective observation of your own existence, because such observation can take place within counterfactuals, and you wouldn’t be able to tell that you are within a counterfactual or actuality other than by reasoning about (or determining) your situation’s actuality status. Like math, existence can’t be perceived by looking at rocks.
In a single universe interpretation, we can posit biogenesis is rare, but we do know it happened at least once in ~two trillion galaxies worth of stars in ~13 billion years.
So this already doesn’t follow, your conclusion is true, but doesn’t require MWI. Even without MWI, observing our own existence doesn’t tell us anything about the probability of biogenesis (and subsequent development of generally intelligent life).
I disagree. I think the fact that our reality branches a la Everett has no bearing on our probability of biogensis.
Consider a second biogenesis that happened recently enough and far away enough that light (i.e., information, causal influence) has not had enough time to travel from it to us. We know such regions of spacetime “recent enough and far away enough” exist and in principle could host life, but since we cannot observe a sign of life or a sign of lack of life from them, they are not relevant to our probability of biogenesis whereas by your logic, they are relevant.
Under MWI of QM, anthropics gets weird.
In a single universe interpretation, we can posit biogenesis is rare, but we do know it happened at least once in ~two trillion galaxies worth of stars in ~13 billion years.
In MWI it could be even rarer—with unlimited branches for wild coincidences of chemistry to occur, we’re necessarily living in a branch where such did occur. Allow for argument’s sake that biogenesis is so rare that branches where life is found are tiny in measure. We find ourselves in such a branch, so anthropics and branching kind of gives us the first miracle for free. But given we’re here, the chance it happened here independently TWICE is vanishingly small again.
If biogenesis is so rare it occurs in a tiny minority of branches only, then in almost all branches where it does occur, it only occurs once.
If I haven’t badly misunderstood something, I think if we accept MWI then it seems much more plausible that we are the only life in the universe.
Anthropics start out weird.
Trying to reason from a single datapoint out of an unknown distribution is always going to be low-information and low-predictive-power. MWI expands the scope of the unknown distribution (or does it? It all adds up to normal, right?), but doesn’t change the underlying unknowns.
In Transparent Newcomb’s Problem, your decision determines whether you existed when you were making the decision. It’s not valid to conclude that you exist merely from subjective observation of your own existence, because such observation can take place within counterfactuals, and you wouldn’t be able to tell that you are within a counterfactual or actuality other than by reasoning about (or determining) your situation’s actuality status. Like math, existence can’t be perceived by looking at rocks.
So this already doesn’t follow, your conclusion is true, but doesn’t require MWI. Even without MWI, observing our own existence doesn’t tell us anything about the probability of biogenesis (and subsequent development of generally intelligent life).
I disagree. I think the fact that our reality branches a la Everett has no bearing on our probability of biogensis.
Consider a second biogenesis that happened recently enough and far away enough that light (i.e., information, causal influence) has not had enough time to travel from it to us. We know such regions of spacetime “recent enough and far away enough” exist and in principle could host life, but since we cannot observe a sign of life or a sign of lack of life from them, they are not relevant to our probability of biogenesis whereas by your logic, they are relevant.