So far, the only effect that all the Omega-talk has had on me is to make me honestly suspect that you guys must be into some kind of mind-over-matter quantum woo.
What on Earth gives you that impression? I agree that scenarios with Omega wil have probably little impact on practical matters, at least in near future, but quantum woo?
In every case I have seen so far where Eliezer has denigrated the standard game solution because it fails to win, he has been analyzing a game involving a physically and philosophically impossible fictional situation.
Why is Omega physically impossible? What is philosophically impossible, in general?
So far, the only effect that all the Omega-talk has had on me is to make me honestly suspect that you guys must be into some kind of mind-over-matter quantum woo.
What on Earth gives you that impression?
Omega makes a decision to put the money in the box, or not. In my model of (MWI) reality, that results in a branching—there are now 2 worlds (one with money, one without). The only problem is, I don’t know which world I am in. Next, I decide whether to one-box or to two-box. In my model, that results in 4 possible worlds now. Or more precisely, someone who knows neither my decision nor Omega’s would count 4 worlds.
But now we are asked to consider some kind of weird quantum correlation between Omega’s choice and my own. Omega’s choice is an event within my own past light-cone. By the usual physical assumptions, my choice should not have any causal influence on his choice. But I am asked to believe that if I choose to two-box, then he will have chosen not to leave money, whereas if I just believe as Omega wishes me to believe, then my choice will make me rich by reaching back and altering the past (selecting my preferred history?). And you ask “What on Earth gives me the impression that this is quantum woo?”
Omega makes a decision to put the money in the box, or not. In my model of (MWI) reality, that results in a branching—there are now 2 worlds (one with money, one without). The only problem is, I don’t know which world I am in. Next, I decide whether to one-box or to two-box. In my model, that results in 4 possible worlds now. Or more precisely, someone who knows neither my decision nor Omega’s would count 4 worlds.
Incorrect. Omega’s decision is no more indeterministic than the output of a calculation. Asking (say) me “Does two plus two equal three?” does not create two worlds, one in which I say “yes” and one in which I say “no”—overwhelmingly I will tell you “no”.
As others have said. Omega-talk is possible in a purely classical world, and is clearer in a classical world. Omega simply scans my brain and deterministically decides whether to put the money in or not. Then I decide whether I take one or two of the boxes. To say my choice should not have any causal influence on his choice is misleading at least. It may be true (depending on how exactly one defines causality), however it doesn’t exclude correlations between the two choices simply because they are both consequences of a common cause (state of my brain and the relevant portion of the world immediately before the scenario begun).
There is no need to include quantumness or even MWI into this scenario, and no certain reason why quantum effects would prevent it from happening. That said, I don’t say that something similar is probably going to happen soon.
That’s the case if you somehow manage to use a quantum coin in your decision. Your decision could be close enough to deterministic that the measure of the words where you decide differently is billions of times or more smaller and can safely be neglected.
Because, in predicting my future decisions, he is performing Laplace demon computations based on Heisenberg demon measurements. And physics rules out such demons.
What is philosophically impossible, in general?
Anything which cannot consistently coexist with what is already known to exist
One possibility: Omega is running this universe as a simulation, and has already run a large number of earlier identical instances.
Ok, that is possible, I suppose. Though it does conflict, in a sense, with the claim that he put the money in the box before I made the decision whether to one-box or two-box. Because, in some sense, I already made that decision in all(?) of those earlier identical simulations.
It is far from sure that the decisions made by human brains rely heavily on quantum effects and that the relevant data can’t be obtained by some non-destructive scanning, without Heisenberg-demonic measurements. The Laplace-demon aspects is in fact a matter of precision. If Omega needed to simulate the brain precisely (unfortunately, the formulations of the paradox here on LW and in the subsequent discussions suggest this), then yes, Omega would have to be a demon. But the Newcomb’s paradox needn’t happen in its idealised version with 100% success of Omega’s predictions to be valid and interesting. If Omega is right only 87% of the time, the paradox still holds, and I don’t see any compelling reason why this should be impossible without postulating demonic abilities.
What on Earth gives you that impression? I agree that scenarios with Omega wil have probably little impact on practical matters, at least in near future, but quantum woo?
Why is Omega physically impossible? What is philosophically impossible, in general?
Omega makes a decision to put the money in the box, or not. In my model of (MWI) reality, that results in a branching—there are now 2 worlds (one with money, one without). The only problem is, I don’t know which world I am in. Next, I decide whether to one-box or to two-box. In my model, that results in 4 possible worlds now. Or more precisely, someone who knows neither my decision nor Omega’s would count 4 worlds.
But now we are asked to consider some kind of weird quantum correlation between Omega’s choice and my own. Omega’s choice is an event within my own past light-cone. By the usual physical assumptions, my choice should not have any causal influence on his choice. But I am asked to believe that if I choose to two-box, then he will have chosen not to leave money, whereas if I just believe as Omega wishes me to believe, then my choice will make me rich by reaching back and altering the past (selecting my preferred history?). And you ask “What on Earth gives me the impression that this is quantum woo?”
Incorrect. Omega’s decision is no more indeterministic than the output of a calculation. Asking (say) me “Does two plus two equal three?” does not create two worlds, one in which I say “yes” and one in which I say “no”—overwhelmingly I will tell you “no”.
Your model ought to be branching at every subatomic event, not at every conscious intelligent choice.
This makes reality (even humans) predictable.
As others have said. Omega-talk is possible in a purely classical world, and is clearer in a classical world. Omega simply scans my brain and deterministically decides whether to put the money in or not. Then I decide whether I take one or two of the boxes. To say my choice should not have any causal influence on his choice is misleading at least. It may be true (depending on how exactly one defines causality), however it doesn’t exclude correlations between the two choices simply because they are both consequences of a common cause (state of my brain and the relevant portion of the world immediately before the scenario begun).
There is no need to include quantumness or even MWI into this scenario, and no certain reason why quantum effects would prevent it from happening. That said, I don’t say that something similar is probably going to happen soon.
That’s the case if you somehow manage to use a quantum coin in your decision. Your decision could be close enough to deterministic that the measure of the words where you decide differently is billions of times or more smaller and can safely be neglected.
Because, in predicting my future decisions, he is performing Laplace demon computations based on Heisenberg demon measurements. And physics rules out such demons.
Anything which cannot consistently coexist with what is already known to exist
One possibility: Omega is running this universe as a simulation, and has already run a large number of earlier identical instances.
There may be many less obvious possibilities, even if you require Omega to be certain rather than just very sure.
Ok, that is possible, I suppose. Though it does conflict, in a sense, with the claim that he put the money in the box before I made the decision whether to one-box or two-box. Because, in some sense, I already made that decision in all(?) of those earlier identical simulations.
It is far from sure that the decisions made by human brains rely heavily on quantum effects and that the relevant data can’t be obtained by some non-destructive scanning, without Heisenberg-demonic measurements. The Laplace-demon aspects is in fact a matter of precision. If Omega needed to simulate the brain precisely (unfortunately, the formulations of the paradox here on LW and in the subsequent discussions suggest this), then yes, Omega would have to be a demon. But the Newcomb’s paradox needn’t happen in its idealised version with 100% success of Omega’s predictions to be valid and interesting. If Omega is right only 87% of the time, the paradox still holds, and I don’t see any compelling reason why this should be impossible without postulating demonic abilities.