I had assumed that microscopic reversibility and a large set of measurements were all that was required. Could you explain where my assumption is wrong ?
Quantum mechanics (in any interpretation, not just many-worlds) makes this impossible even in principle; the necessary information can’t be retrieved, and may not even be present in any one quantum outcome. Even under classical mechanics, you need exact measurements of essentially the whole universe, including photons on their way to infinity, meaning that you need sensors and computers that are larger than and outside of the universe.
To actually retrieve the computation they embodied? That which made them, well, them?
My personal guess is that, barring the possibility of “it turns out something like time travel is possible after all”, and even then, the trickiness of somehow reaching back to before the machine was built, or some other improbable major physics revolution that would let us retrieve information from the past, well, sadly, I’d have to guess no.
Of course, I’d be ecstatic if it turned out there was a way. I’m just not expecting it. :(
No consensus. Many people think we will eventually invent tech to relaunch cryonically frozen people, and many other people disagree, but pretty much no one sees any hope for reconstructing people whose brains have already decomposed.
Depends on what you think of as a person. If you reconstructed someone based on your and other people’s memories of them and whatever other record there exists, they may well be just what you remember. That might be enough to make you happy. Of course, the recreated person won’t be the same as whoever they are modeled after.
The thing I love about lesswrong is that you’re never more than one step away from an epistemological landmine, and even a simple ordinary question like “can we raise the dead” ends up as “is a person the same person just because you have no way of knowing that they aren’t the same person ?”.
In a Big World, though, there is no one person who generated those memories. If you can accurately approximate the objective distribution of those people, and draw someone at random from it, that seems as good as resurrection to me. (Assuming quantum immortality/no Death events, and strictly patternist personal identity/causal continuity is unimportant; I see no reason not to assume these, but apparently some disagree.)
If you can accurately approximate the objective distribution of those people, and draw someone at random from it, that seems as good as resurrection to me.
How might we go about doing this? One method I can see is to make a large number of measurements on physical objects/systems correlated with the deceased persons (in the information theoretic sense), then do a full quantum simulation of the universe starting from initial low-entropy conditions, and look for branches that contain systems that match those measurements, then backtrack the simulation a bit to where those persons are still alive.
I can’t parse your assumptions—are they separate assumptions, or are you implying that they’re equivalent? Quantum immortality, in particular, seems irrelevant to the argument. I don’t see what the disagreement is in the link, except to QI.
In a Big World, though, there is no one person who generated those memories
If we define a “Big World” to be, say Tegmark Level I infinite universe, then it is still the case that one particular space/time localized stable pattern realized in organic molecules did create the memories. There are other “copies” of that same pattern 10^118 meters away, but they are not here. I am unconvinced of your somewhat radical statement here.
It’s a much older idea than that. One of the best stories on it that I’ve read is by… Ray Bradbury, perhaps? I’m not sure. It’s about a long dead classical composer whose personality and memories are reconstructed inside a living person’s brain. He remembers his life, he remembers writing music and even remembers dying… but discovers that he can’t compose anything new. Anyone know what I’m talking about?
Vaguely remember as well. I recall a girl doing research on this person on the nth floor of library -- that is somehow connected. This person is simulated in a virtual world, and then realizes he’s a simulation when he cannot compose anything new. The realization occurs amidst Greek or Spanish architecture during a sunrise. Same story? But which?
I probe my brain for another clue… I learned the word “hegemony” while reading this book. Googling “hegemony” and “science fiction” eventually gives Hyperion by Dan Simmons. Google is awesome.
But it was the poet Keats that was simulated.
That was 1989. I bet we can think of an older example. A person resurrected but lacking their “essence” is older than AI.
That isn’t the story I’m thinking about. In the story the reconstructed person is in a real body, a real mind—he’s been mapped onto a living person’s brain. Since his style of music is no longer popular, he produces a new symphony in the style of the day, despite knowing it’s still a rehash of his previous work. At the end of the performance, everyone applauds… but they’re actually applauding the neuroscientists for their work, not the composer for his, and in the end he gets ‘erased’ so that the test subject can have his mind back. It might be a story from the 50s, since I seem to remember reading it in an anthology of such.
Yes, that’s it! Thank you so much. It’s definitely from that 50′s pulp anthology, which I’m sure is packed away in a box somewhere. The 50′s were great for science fiction when you consider the magnitude of the ideas they loved to deal with… often far more sophisticated and penetrating than the military SF of today or even the time travel or alien encounters of the 80s and 90s.
A person is nature plus nurture, and besides, I’m not even sure if DNA alone would produce the same baby. Epigenetics, womb variation, and whatnot all have an effect even before a child is born.
You mean without brute-forcing it by creating every conceivable person? (I’m sure I read something in Deutsch to the effect that infinite computing power might be available in certain universes...)
Not very useful if you want to interact with the specific person you want resurrected. You also risk creating a lot of unnecessary suffering in the created persons.
What’s the current view on whether there’s enough information available to reconstruct the dead ?
(by which I mean the unfrozen dead)
Resurrecting the ancient dead requires that our models of physics be wrong in character, not just detail.
I had assumed that microscopic reversibility and a large set of measurements were all that was required. Could you explain where my assumption is wrong ?
Quantum mechanics (in any interpretation, not just many-worlds) makes this impossible even in principle; the necessary information can’t be retrieved, and may not even be present in any one quantum outcome. Even under classical mechanics, you need exact measurements of essentially the whole universe, including photons on their way to infinity, meaning that you need sensors and computers that are larger than and outside of the universe.
To actually retrieve the computation they embodied? That which made them, well, them?
My personal guess is that, barring the possibility of “it turns out something like time travel is possible after all”, and even then, the trickiness of somehow reaching back to before the machine was built, or some other improbable major physics revolution that would let us retrieve information from the past, well, sadly, I’d have to guess no.
Of course, I’d be ecstatic if it turned out there was a way. I’m just not expecting it. :(
No consensus. Many people think we will eventually invent tech to relaunch cryonically frozen people, and many other people disagree, but pretty much no one sees any hope for reconstructing people whose brains have already decomposed.
Depends on what you think of as a person. If you reconstructed someone based on your and other people’s memories of them and whatever other record there exists, they may well be just what you remember. That might be enough to make you happy. Of course, the recreated person won’t be the same as whoever they are modeled after.
The thing I love about lesswrong is that you’re never more than one step away from an epistemological landmine, and even a simple ordinary question like “can we raise the dead” ends up as “is a person the same person just because you have no way of knowing that they aren’t the same person ?”.
In a Big World, though, there is no one person who generated those memories. If you can accurately approximate the objective distribution of those people, and draw someone at random from it, that seems as good as resurrection to me. (Assuming quantum immortality/no Death events, and strictly patternist personal identity/causal continuity is unimportant; I see no reason not to assume these, but apparently some disagree.)
How might we go about doing this? One method I can see is to make a large number of measurements on physical objects/systems correlated with the deceased persons (in the information theoretic sense), then do a full quantum simulation of the universe starting from initial low-entropy conditions, and look for branches that contain systems that match those measurements, then backtrack the simulation a bit to where those persons are still alive.
Is that what you had in mind?
I can’t parse your assumptions—are they separate assumptions, or are you implying that they’re equivalent? Quantum immortality, in particular, seems irrelevant to the argument. I don’t see what the disagreement is in the link, except to QI.
If we define a “Big World” to be, say Tegmark Level I infinite universe, then it is still the case that one particular space/time localized stable pattern realized in organic molecules did create the memories. There are other “copies” of that same pattern 10^118 meters away, but they are not here. I am unconvinced of your somewhat radical statement here.
Straight from the Caprica pilot.
It’s a much older idea than that. One of the best stories on it that I’ve read is by… Ray Bradbury, perhaps? I’m not sure. It’s about a long dead classical composer whose personality and memories are reconstructed inside a living person’s brain. He remembers his life, he remembers writing music and even remembers dying… but discovers that he can’t compose anything new. Anyone know what I’m talking about?
Vaguely remember as well. I recall a girl doing research on this person on the nth floor of library -- that is somehow connected. This person is simulated in a virtual world, and then realizes he’s a simulation when he cannot compose anything new. The realization occurs amidst Greek or Spanish architecture during a sunrise. Same story? But which?
I probe my brain for another clue… I learned the word “hegemony” while reading this book. Googling “hegemony” and “science fiction” eventually gives Hyperion by Dan Simmons. Google is awesome.
But it was the poet Keats that was simulated.
That was 1989. I bet we can think of an older example. A person resurrected but lacking their “essence” is older than AI.
That isn’t the story I’m thinking about. In the story the reconstructed person is in a real body, a real mind—he’s been mapped onto a living person’s brain. Since his style of music is no longer popular, he produces a new symphony in the style of the day, despite knowing it’s still a rehash of his previous work. At the end of the performance, everyone applauds… but they’re actually applauding the neuroscientists for their work, not the composer for his, and in the end he gets ‘erased’ so that the test subject can have his mind back. It might be a story from the 50s, since I seem to remember reading it in an anthology of such.
A Work Of Art, by James Blish. Enjoy..
Yes, that’s it! Thank you so much. It’s definitely from that 50′s pulp anthology, which I’m sure is packed away in a box somewhere. The 50′s were great for science fiction when you consider the magnitude of the ideas they loved to deal with… often far more sophisticated and penetrating than the military SF of today or even the time travel or alien encounters of the 80s and 90s.
Oh yes !
Some of the ideas though—they’re not the sort you would want spread.
Get hold of their DNA, and you might be able to get somewhere fairly soon.
E.g. see my “Celebrity cloning” video.
A person is nature plus nurture, and besides, I’m not even sure if DNA alone would produce the same baby. Epigenetics, womb variation, and whatnot all have an effect even before a child is born.
You mean without brute-forcing it by creating every conceivable person? (I’m sure I read something in Deutsch to the effect that infinite computing power might be available in certain universes...)
Not very useful if you want to interact with the specific person you want resurrected. You also risk creating a lot of unnecessary suffering in the created persons.