It depends on what you mean by “I”. This is the crux of the matter. MWI takes a God’s-eye perspective and looks at the whole wave function. On that view, there are many you’s (i.e. many slices of the wave function that contain macroscopic systems of mutually entangled particles that perceive themselves to be you).
QIT takes the perspective of the-you-that-you-currently-perceive-yourself-to-be. You will only ever perceive one of that kind of you.
For the purposes of making decisions it makes more sense to take the latter perspective because it’s the-latter-kind-of-you that is making the decisions and has to live with the consequences.
I would say that a major difference between MWI and various collapse interpretations is that there are situations where according to collapse interpretations there most likely will be no future you; but according to MWI there surely will, although their amplitude is low (the aforementioned Russian roulette is one such situation, for instance). I find it somewhat difficult to think about those from the perspective you advocate.
No. Not “will”. IS. If you’re going to take the God’s eye view then you have to let go of your intuitions about time along with your intuitions about classical reality. The wave function is a static four-dimensional thing. Time emerges from the wave function in exactly the same way that classical reality does. You have to be careful not to apply terminology from the mortal’s-eye-view to the God’s-eye-view. That’s how you get yourself into trouble.
UPDATE: Here is a popular article about how time emerges from entanglement.
I think what I said applies when you take a first-person point of view. If you’re a participant in a quantum suicide experiment, then if you expect a collapse interpretation to be an accurate description of reality, you should expect to eventually be hit by a bullet and die. But both MWI and QIT predict that you will continuously notice that the gun doesn’t fire. The difference is not in the point of view taken, it’s in the fact that the parts of the wavefunction that contain a (from first-person eye-view) future version of the participant actually are there.
But both MWI and QIT predict that you will continuously notice that the gun doesn’t fire.
No, that’s not quite true. QIT predicts that if you notice anything then you will notice that the gun didn’t fire. But QIT does not guarantee that you will notice anything. You could just die.
Notice (!) that when you start to talk about “noticing” things you are tacitly bringing consciousness into the discussion, which is a whole ‘nuther can o’ philosophical worms.
It depends on what you mean by “I”. This is the crux of the matter. MWI takes a God’s-eye perspective and looks at the whole wave function. On that view, there are many you’s (i.e. many slices of the wave function that contain macroscopic systems of mutually entangled particles that perceive themselves to be you).
QIT takes the perspective of the-you-that-you-currently-perceive-yourself-to-be. You will only ever perceive one of that kind of you.
For the purposes of making decisions it makes more sense to take the latter perspective because it’s the-latter-kind-of-you that is making the decisions and has to live with the consequences.
I would say that a major difference between MWI and various collapse interpretations is that there are situations where according to collapse interpretations there most likely will be no future you; but according to MWI there surely will, although their amplitude is low (the aforementioned Russian roulette is one such situation, for instance). I find it somewhat difficult to think about those from the perspective you advocate.
No. Not “will”. IS. If you’re going to take the God’s eye view then you have to let go of your intuitions about time along with your intuitions about classical reality. The wave function is a static four-dimensional thing. Time emerges from the wave function in exactly the same way that classical reality does. You have to be careful not to apply terminology from the mortal’s-eye-view to the God’s-eye-view. That’s how you get yourself into trouble.
UPDATE: Here is a popular article about how time emerges from entanglement.
I think what I said applies when you take a first-person point of view. If you’re a participant in a quantum suicide experiment, then if you expect a collapse interpretation to be an accurate description of reality, you should expect to eventually be hit by a bullet and die. But both MWI and QIT predict that you will continuously notice that the gun doesn’t fire. The difference is not in the point of view taken, it’s in the fact that the parts of the wavefunction that contain a (from first-person eye-view) future version of the participant actually are there.
No, that’s not quite true. QIT predicts that if you notice anything then you will notice that the gun didn’t fire. But QIT does not guarantee that you will notice anything. You could just die.
Notice (!) that when you start to talk about “noticing” things you are tacitly bringing consciousness into the discussion, which is a whole ‘nuther can o’ philosophical worms.
See also my response to akvadrako.