You can rewrite the doomsday question into more objective terms: “given evidence that N people have previously come into existence, what update should be made to the credence distribution for the total number of people to ever come into existence?”
To me, that version of the doomsday question is extremely unconvincing for a very different reason. It is using only the most basic (single number, N) aspect of the available data. We could go one step more sophisticated and get the number of people born last year and extrapolate that number of annual births out to eternity. Or we could go yet another step more sophisticated and fit an exponential to the births per year graph to extrapolate instead. Presumably we could go much further, fitting ever more complex models to a wider set of available data. Perhaps even trying to include models of the Earth’s calorific budget or the likelihood of nuclear war.
Its not clear to me why we would put any credence in the doomsday argument (take N, approximately double it) specifically, out of all the available models.
It’s not meant to be convincing, since it doesn’t make any argument. It’s a version of the question.
You can obviously make models of the future, using whatever hypotheses you like. Those models then should be weighted by complexity of hypotheses and credence that they will accurately reflect the future based partly on retrodiction of the past, and the results will modify the very broad distribution that you get by taking nothing but birth rank. If you use a SSA evidence model, then this broad distribution looks something like P(T > kN) ~ 1/k.
If you take all the credible future models appropriately weighted and get a relatively low credence of doomsday before another N people come into existence, then the median of the posterior distribution of total people will be greater than that of the doomsday prior distribution.
This rewrite is still perspective dependent as it involves the concept of “now” to define who “previously come into existence”. i.e. it is different for the current generation vs people in the axial age. Whereas the Doomsday Argument uses a detached viewpoint that is time-indifferent. So the problem still remains.
I don’t think the Doomsday argument claims to be time-independent. It seems to me to be specifically time-dependent—as is any update. And there’s nothing inherently wrong with that: we are all trying to be the most right that we can be given the information we have access to, our point of view.
I didn’t explicitly claim so. But it involves reasoning from a perspective that is impartial to any moment. This independency manifested in its core assumption: that one should regard themself to be randomly selected from all observers from its reference class from past, present and future
I think I don’t understand what makes you say that anthropic reasoning requires “reasoning from a perspective that is impartial to any moment”. The way I think about this is the following:
If I imagine how an omnitemporal, omniscient being would see me, I imagine they would see me as a randomly selected sample from all humans, past present and future (which don’t really exist for the being).
From my point of view, it does feel weird to say that “I’m a randomly selected sample”, but I certainly don’t feel like there is anything special about the year I was born. This, combined with the fact that I’m obviously human, is just a from-my-point-of-view way of saying the same thing. I’m a human and I have no reason to belive the year I was born is special == I’m a human whose birth year is a sample randomly taken from the population of all possible humans.
What changes when you switch perspectives is just the words, not the point. I guess you’re thinking about this differently? Do you think you can state where we’re disagreeing?
When you say the time of your birth is not special, you are already trying to judge it objectively. For you personally, the moment of your birth is special. And more relevantly to the DA, from a first-person perspective, the moment “now” is special.
From an objective viewpoint, discussing a specific observer or a specific moment requires some explanation, something process pointing to it. e.g. a sampling process. Otherwise, it fails to be objective by inherently focusing on someone/sometime.
From a first-person perspective, discussions based on “I” and “now” doesn’t require such an explanation. It’s inherently understandable. The future is just moments after “now”. Its prediction ought to be based on my knowledge of the present and past.
What the doomsday argument saying is, the fact “I am this person” (living now) shall be treated the same way as if someone from the objective viewpoint in 1, performs a random sampling and finds me (now). The two cases are supposed to be logically equivalent. So the two viewpoints can say the same thing. I’m saying let’s not make that assumption. And in this case, the objective viewpoint cannot say the same thing as the first-person perspective. So we can’t switch perspectives here.
You can rewrite the doomsday question into more objective terms: “given evidence that N people have previously come into existence, what update should be made to the credence distribution for the total number of people to ever come into existence?”
To me, that version of the doomsday question is extremely unconvincing for a very different reason. It is using only the most basic (single number, N) aspect of the available data. We could go one step more sophisticated and get the number of people born last year and extrapolate that number of annual births out to eternity. Or we could go yet another step more sophisticated and fit an exponential to the births per year graph to extrapolate instead. Presumably we could go much further, fitting ever more complex models to a wider set of available data. Perhaps even trying to include models of the Earth’s calorific budget or the likelihood of nuclear war.
Its not clear to me why we would put any credence in the doomsday argument (take N, approximately double it) specifically, out of all the available models.
It’s not meant to be convincing, since it doesn’t make any argument. It’s a version of the question.
You can obviously make models of the future, using whatever hypotheses you like. Those models then should be weighted by complexity of hypotheses and credence that they will accurately reflect the future based partly on retrodiction of the past, and the results will modify the very broad distribution that you get by taking nothing but birth rank. If you use a SSA evidence model, then this broad distribution looks something like P(T > kN) ~ 1/k.
If you take all the credible future models appropriately weighted and get a relatively low credence of doomsday before another N people come into existence, then the median of the posterior distribution of total people will be greater than that of the doomsday prior distribution.
This rewrite is still perspective dependent as it involves the concept of “now” to define who “previously come into existence”. i.e. it is different for the current generation vs people in the axial age. Whereas the Doomsday Argument uses a detached viewpoint that is time-indifferent. So the problem still remains.
I don’t think the Doomsday argument claims to be time-independent. It seems to me to be specifically time-dependent—as is any update. And there’s nothing inherently wrong with that: we are all trying to be the most right that we can be given the information we have access to, our point of view.
I didn’t explicitly claim so. But it involves reasoning from a perspective that is impartial to any moment. This independency manifested in its core assumption: that one should regard themself to be randomly selected from all observers from its reference class from past, present and future
I think I don’t understand what makes you say that anthropic reasoning requires “reasoning from a perspective that is impartial to any moment”. The way I think about this is the following:
If I imagine how an omnitemporal, omniscient being would see me, I imagine they would see me as a randomly selected sample from all humans, past present and future (which don’t really exist for the being).
From my point of view, it does feel weird to say that “I’m a randomly selected sample”, but I certainly don’t feel like there is anything special about the year I was born. This, combined with the fact that I’m obviously human, is just a from-my-point-of-view way of saying the same thing. I’m a human and I have no reason to belive the year I was born is special == I’m a human whose birth year is a sample randomly taken from the population of all possible humans.
What changes when you switch perspectives is just the words, not the point. I guess you’re thinking about this differently? Do you think you can state where we’re disagreeing?
When you say the time of your birth is not special, you are already trying to judge it objectively. For you personally, the moment of your birth is special. And more relevantly to the DA, from a first-person perspective, the moment “now” is special.
From an objective viewpoint, discussing a specific observer or a specific moment requires some explanation, something process pointing to it. e.g. a sampling process. Otherwise, it fails to be objective by inherently focusing on someone/sometime.
From a first-person perspective, discussions based on “I” and “now” doesn’t require such an explanation. It’s inherently understandable. The future is just moments after “now”. Its prediction ought to be based on my knowledge of the present and past.
What the doomsday argument saying is, the fact “I am this person” (living now) shall be treated the same way as if someone from the objective viewpoint in 1, performs a random sampling and finds me (now). The two cases are supposed to be logically equivalent. So the two viewpoints can say the same thing. I’m saying let’s not make that assumption. And in this case, the objective viewpoint cannot say the same thing as the first-person perspective. So we can’t switch perspectives here.