The problem with the Doomsday Argument is not it’s too pessimistic about the future. One can be as optimistic or pessimistic about humanity’s future as he likes. But according to DA that prior belief must inevitably get much bleaker once he considers his own birth rank.
One’s own birth rank is information about which physical person the first person is: “out of all the human beings which one is me”. It is perspective-specific, yet it is used to make conclusions on something perspective-independent: the total number of human beings ever exists. If DA’s logic is correct, then I can have supernatural predicting power as long as it is related to the size of the reference class. E.g. in the sleeping beauty problem, I can predict the probability of heads for a fair coin yet to be tossed to be 2⁄3. Or as jessicata pointed out earlier, consider’s Adam and Eve problem by Bostrom.
I don’t support SIA either. Because it uses the existence of the first person as evidence. That boosts the size of the reference class which counters the DA. But that leads to biasing to theories with a bigger reference class. I constantly see the claim that SIA is independent of how you define the reference class. That is not true. Are brains-in-vats in the reference class? What about programmes simulating humans or Boltzmann brains? Whether they shall be considered valid “observers”, i.e. in the same reference class as me, will greatly change the judgments on the relating theories once SIA is applied.
I think the problem lies in the assumption of treating the first-person perspective as an observation selection effect. e.g. considering “I” a random sample from all observers. There is no basis for such assumptions. From a first-person perspective, one naturally knows who “I” is. It is primitively clear, no need to explain it with a selection process. On the other hand, if we wish to not take any specific perspective: to reason “objectively”, then there shouldn’t be an “I” in the logic at all.
Not sure what you mean.
Doomsday argument is about how to think about the information that the first-person “I” is a particular physical person. It suggests treating it the same way as if a random sampling process has selected said physical person. SIA agrees with using sampling process, but disagrees with the range it is sampled from.
The problem with the Doomsday Argument is not it’s too pessimistic about the future. One can be as optimistic or pessimistic about humanity’s future as he likes. But according to DA that prior belief must inevitably get much bleaker once he considers his own birth rank.
One’s own birth rank is information about which physical person the first person is: “out of all the human beings which one is me”. It is perspective-specific, yet it is used to make conclusions on something perspective-independent: the total number of human beings ever exists. If DA’s logic is correct, then I can have supernatural predicting power as long as it is related to the size of the reference class. E.g. in the sleeping beauty problem, I can predict the probability of heads for a fair coin yet to be tossed to be 2⁄3. Or as jessicata pointed out earlier, consider’s Adam and Eve problem by Bostrom.
I don’t support SIA either. Because it uses the existence of the first person as evidence. That boosts the size of the reference class which counters the DA. But that leads to biasing to theories with a bigger reference class. I constantly see the claim that SIA is independent of how you define the reference class. That is not true. Are brains-in-vats in the reference class? What about programmes simulating humans or Boltzmann brains? Whether they shall be considered valid “observers”, i.e. in the same reference class as me, will greatly change the judgments on the relating theories once SIA is applied.
I think the problem lies in the assumption of treating the first-person perspective as an observation selection effect. e.g. considering “I” a random sample from all observers. There is no basis for such assumptions. From a first-person perspective, one naturally knows who “I” is. It is primitively clear, no need to explain it with a selection process. On the other hand, if we wish to not take any specific perspective: to reason “objectively”, then there shouldn’t be an “I” in the logic at all.
Check this thought-experiment about my view.
[edited]
Not sure what you mean. Doomsday argument is about how to think about the information that the first-person “I” is a particular physical person. It suggests treating it the same way as if a random sampling process has selected said physical person. SIA agrees with using sampling process, but disagrees with the range it is sampled from.