It seems like maybe you think I think the Doomsday Argument is about drawing inferences about the past, or something? The Doomsday Argument isn’t [necessarily] about drawing inferences about what happened in the past. It’s about using factors that aren’t particularly in the past, present, or future, to constrain our expectations of what will happen in the future, and our model of reality outside time.
My response to that is that this would be the case if we didn’t have more information, but we do, and thus we can update away from the doomsday argument, because we have way more evidence than the doomsday argument assumes.
It’s an underconstrained model because of that, and a lot of anthropic reasoning’s weird results fundamentally come from intentionally ignoring evidence that could be true in a different world, but is not the world we live in, and we have more information on constraints that changes the probabilities of the doomsday argument drastically.
To be clear, I think the main flaw of a lot of anthropics in practice is ignoring other sources of evidence, and I suspect a lot of the problem really does boil down to conservation of expected evidence violations plus ignoring other, much larger sources of evidence.
This is why the most general versions of the simulation hypothesis/Mathematical Universe Hypothesis/computational functionalism hypothesis for consciousness are not properly speaking valid Bayesian hypotheses, because every outcome could count as confirmation of the theory, so it is utterly useless for prediction.
It’s a great universal ontology, but it’s predictive power is precisely 0.
More positively speaking, the hypotheses are just the assumed things they have for Bayesians, similarly to how logical omniscience is just assumed for Bayesians, and thus it’s great to have a universal tool-kit, but that does come with the downside of having 0 ability to predict anything (because it contains everything).
My response to that is that this would be the case if we didn’t have more information, but we do, and thus we can update away from the doomsday argument, because we have way more evidence than the doomsday argument assumes.
It’s an underconstrained model because of that, and a lot of anthropic reasoning’s weird results fundamentally come from intentionally ignoring evidence that could be true in a different world, but is not the world we live in, and we have more information on constraints that changes the probabilities of the doomsday argument drastically.
I agree with this!
“Update away from” does not imply “discard”.
To be clear, I think the main flaw of a lot of anthropics in practice is ignoring other sources of evidence, and I suspect a lot of the problem really does boil down to conservation of expected evidence violations plus ignoring other, much larger sources of evidence.
On this:
This is why the most general versions of the simulation hypothesis/Mathematical Universe Hypothesis/computational functionalism hypothesis for consciousness are not properly speaking valid Bayesian hypotheses, because every outcome could count as confirmation of the theory, so it is utterly useless for prediction.
It’s a great universal ontology, but it’s predictive power is precisely 0.
More positively speaking, the hypotheses are just the assumed things they have for Bayesians, similarly to how logical omniscience is just assumed for Bayesians, and thus it’s great to have a universal tool-kit, but that does come with the downside of having 0 ability to predict anything (because it contains everything).