As soon as we’ve established the notion of probability experiment that approximates our knowledge about the physical process that we are talking about—we are done. This works exactly the same way whether you are not sure about the outcome of a coin toss, oddness or evenness of an unknown to you digit of pi, or whether you live on a tallest or the coldest mountain.
And if you find yourself unable to formally express some reasoning like that—this is a feature not a bug. It shows when your reasoning becomes incoherent.
A root confusion may be whether different pasts could have caused the same present, and hence whether I can have multiple simultaneous possible parents, in an “indexical-uncertainty” sense, in the same way that I can have multiple simultaneous possible future children.
I think our disagreement is that you believe that one always has multiple possible parents as some metaphysical fact about the universe, while I believe that the notion of possible parent is only appropriate for a person who is in a state of uncertainty about who their parents are. Does that sound right to you?
The same standard physics theories that say it’s impossible to be certain about the future, also say it’s impossible to be certain about the past.
Consider, a coin is about to be tossed. You are indifferent between two outcomes. Then the coin is tossed and shown to you and you reflect on it a second later. Technically you can’t be absolutely sure that you didn’t misremember the outcome. But you are much more confident than beforehand, to the point where we usually just approximate away whatever uncertainty is left for the sake of simplicity.
we’re still left uncomfortably aware of our subjective inability to say exactly what the future and past are and why exactly they must be that way
Until we learn what and why they are with a high level of confidence. Then we are much less uncomfortable about it.
And yes there is still a chance that all that we know is wrong, souls are real and are allocated to humans throughout history by a random process and therefore the assumptions of Doomsday Argument just so happened to be true. Conditionally on that Doomsday Inference is true. But to the best of our knowledge this is extremely unlikely, so we shouldn’t worry about it too much and should frame Doomsday Argument appropriately.
If you can’t generate your parents’ genomes and everything from memory, then yes, you are in a state of uncertainty about who they are, in the same qualitative way you are in a state of uncertainty about who your young children will grow up to be.
Ditto for the isomorphism between your epistemic state w.r.t. never-met grandparents vs your epistemic state w.r.t. not-yet-born children.
It may be helpful to distinguish the subjective future, which contains the outcomes of all not-yet-performed experiments [i.e. all evidence/info not yet known] from the physical future, which is simply a direction in physical time.
If you can’t generate your parents’ genomes and everything from memory, then yes, you are in a state of uncertainty about who they are, in the same qualitative way you are in a state of uncertainty about who your young children will grow up to be.
Here you seem to confuse “which person has quality X” with “what are all the other qualities that a person, who has quality X has”.
I’m quite confident about which people are my parents. I’m less confident about all the qualities that my parents have. The former is relevant to Doomsday argument, the latter is not.
And even if I had no idea about who my parents are I’d still be pretty confident that they were born in the last century not in 6th BC.
It may be helpful to distinguish the subjective future, which contains the outcomes of all not-yet-performed experiments [i.e. all evidence/info not yet known] from the physical future, which is simply a direction in physical time
As soon as we’ve established the notion of probability experiment that approximates our knowledge about the physical process that we are talking about—we are done. This works exactly the same way whether you are not sure about the outcome of a coin toss, oddness or evenness of an unknown to you digit of pi, or whether you live on a tallest or the coldest mountain.
And if you find yourself unable to formally express some reasoning like that—this is a feature not a bug. It shows when your reasoning becomes incoherent.
I think our disagreement is that you believe that one always has multiple possible parents as some metaphysical fact about the universe, while I believe that the notion of possible parent is only appropriate for a person who is in a state of uncertainty about who their parents are. Does that sound right to you?
This is really beside the point.
Consider, a coin is about to be tossed. You are indifferent between two outcomes. Then the coin is tossed and shown to you and you reflect on it a second later. Technically you can’t be absolutely sure that you didn’t misremember the outcome. But you are much more confident than beforehand, to the point where we usually just approximate away whatever uncertainty is left for the sake of simplicity.
Until we learn what and why they are with a high level of confidence. Then we are much less uncomfortable about it.
And yes there is still a chance that all that we know is wrong, souls are real and are allocated to humans throughout history by a random process and therefore the assumptions of Doomsday Argument just so happened to be true. Conditionally on that Doomsday Inference is true. But to the best of our knowledge this is extremely unlikely, so we shouldn’t worry about it too much and should frame Doomsday Argument appropriately.
If you can’t generate your parents’ genomes and everything from memory, then yes, you are in a state of uncertainty about who they are, in the same qualitative way you are in a state of uncertainty about who your young children will grow up to be.
Ditto for the isomorphism between your epistemic state w.r.t. never-met grandparents vs your epistemic state w.r.t. not-yet-born children.
It may be helpful to distinguish the subjective future, which contains the outcomes of all not-yet-performed experiments [i.e. all evidence/info not yet known] from the physical future, which is simply a direction in physical time.
Here you seem to confuse “which person has quality X” with “what are all the other qualities that a person, who has quality X has”.
I’m quite confident about which people are my parents. I’m less confident about all the qualities that my parents have. The former is relevant to Doomsday argument, the latter is not.
And even if I had no idea about who my parents are I’d still be pretty confident that they were born in the last century not in 6th BC.
Sure. But I don’t see how it’s relevant here.