Stuart, sorry for being lazy or something, but “SIA” and “SSA” aside, I just don’t see how I could be one of the first few billion ever to live, in a cosmic civilization whose ultimate population is in the quadrillions, and not be in a historical position that is apriori unlikely, with odds of about 1 million to 1 against. Do you have a comment on this naive argument?
Imagine these cosmic civilizations of different sizes exist in parallel universes. Then you are more likely to exist in the universe with many humans than with few. This exactly compensates for the effect you describe.
More pictorially: there are two parallel universes (think of them as different planets). In one, Mitchell Porter lives and nobody else. In the other, Mitchell Porter lives along with a billion other people.
But from your perspective, these other people are irrelevant: what you care about is that there are two Mitchell Porters, one in each universe/planet. So you should feel that it’s equally likely that you are in either universe.
The usual way that I dispel the illusion of a ‘reference class’ based on something like sentience (as opposed to something sensible like the class of beings making the same observations as you) is by asking what inferences a nonsentient AI should make, but of course that line of argument won’t convince Mitchell.
The situation may be a priori unlikely, but I don’t think it’s at all presumptuous to argue that the amount of evidence available to us is enough to shift the likelihood upwards dramatically.
The Doomsday Argument applies to any population of any species, ever. I think it’s pretty reasonable to say that humans are in a pretty exceptional position out of the set of all known species.
Here’s an idea, based on Quantum Mechanics, by someone who hardly knows any Quantum Mechanics at all—therefore it’s probably complete nonsense. (If it’s not nonsense, feel free to name said solution after me. :-)
Doesn’t the amplitude of a configuration need to be squared in order to figure out the probability of its observation?
And also don’t configurations tend to split more than merge?
So doesn’t that mean that if an amplitude-10 configuration splits to two amplitude-5 configurations, the relative probability of the first configuration is 10^2=100 compared to 5^2 + 5^2=50?
So, to put it differently, don’t earlier instances have a greater probability of observation than later instances?
It is the squared magnitude of quantum amplitude that is conserved, not the quantum amplitude itself (which is represented as a complex number). Otherwise, the Born rule would not produce coherent probabilities.
Concretely: A configuration with amplitude 10 (and measure 100) will split its flow into two configurations 7.07 (and hence measure 50 each).
(Of course these are actually blobs whose measure is a multidimensional integral over the amplitude’s squared modulus, and we’d be looking at the equivalent of 5 + 5i and 5 − 5i so that they linearly sum to the original 10 while having length 7.07 each, but whatever...)
Stuart, sorry for being lazy or something, but “SIA” and “SSA” aside, I just don’t see how I could be one of the first few billion ever to live, in a cosmic civilization whose ultimate population is in the quadrillions, and not be in a historical position that is apriori unlikely, with odds of about 1 million to 1 against. Do you have a comment on this naive argument?
It’s a tough job, but someone has to do it :P
“Were you born on Earth before interstellar spaceflight? Enlist in the Confessor corps today! Service guarantees citizenship!”
It is a tough job, but I would rather be born now than any other era: I want to be a Confessor when I grow up.
Imagine these cosmic civilizations of different sizes exist in parallel universes. Then you are more likely to exist in the universe with many humans than with few. This exactly compensates for the effect you describe.
More pictorially: there are two parallel universes (think of them as different planets). In one, Mitchell Porter lives and nobody else. In the other, Mitchell Porter lives along with a billion other people.
But from your perspective, these other people are irrelevant: what you care about is that there are two Mitchell Porters, one in each universe/planet. So you should feel that it’s equally likely that you are in either universe.
The usual way that I dispel the illusion of a ‘reference class’ based on something like sentience (as opposed to something sensible like the class of beings making the same observations as you) is by asking what inferences a nonsentient AI should make, but of course that line of argument won’t convince Mitchell.
The situation may be a priori unlikely, but I don’t think it’s at all presumptuous to argue that the amount of evidence available to us is enough to shift the likelihood upwards dramatically.
The Doomsday Argument applies to any population of any species, ever. I think it’s pretty reasonable to say that humans are in a pretty exceptional position out of the set of all known species.
Here’s an idea, based on Quantum Mechanics, by someone who hardly knows any Quantum Mechanics at all—therefore it’s probably complete nonsense. (If it’s not nonsense, feel free to name said solution after me. :-)
Doesn’t the amplitude of a configuration need to be squared in order to figure out the probability of its observation? And also don’t configurations tend to split more than merge? So doesn’t that mean that if an amplitude-10 configuration splits to two amplitude-5 configurations, the relative probability of the first configuration is 10^2=100 compared to 5^2 + 5^2=50?
So, to put it differently, don’t earlier instances have a greater probability of observation than later instances?
It is the squared magnitude of quantum amplitude that is conserved, not the quantum amplitude itself (which is represented as a complex number). Otherwise, the Born rule would not produce coherent probabilities.
Concretely: A configuration with amplitude 10 (and measure 100) will split its flow into two configurations 7.07 (and hence measure 50 each).
(Of course these are actually blobs whose measure is a multidimensional integral over the amplitude’s squared modulus, and we’d be looking at the equivalent of 5 + 5i and 5 − 5i so that they linearly sum to the original 10 while having length 7.07 each, but whatever...)