Looking down on the double slit experiment from outside you can ask questions like “what is the probability that the photon will go through each slot?”. You have no “givens” to affect your probabilities so you say “50/50”, and you’re right. The photon goes through both, but since there’s only one photon (conserved number of photons), it does it in a particular (some what obvious) way: it combines the states “left/not right” and “not left/right”.
Now say you’re presented with two doors. You also can’t be in the state “right and left”. Now when you go through one door, because you’re interacting with yourself, you have givens that affect the probabilities. Ask yourself, “What is the probability that I went through the left door, given that I just went through the right door?” Zero, baby!
The version of you that when through the left door will be able to make a very similar calculation.
The explainer doesn’t seem to imply the choice is equivalent to a quantum split unless I’m missing something? I’ve had Jeff’s reservation every time I’ve heard this argument. It seems like it would just be a huge coincidence for our decisions to actually correspond to splits. Subjective senses of uncertainty may not equal actual lack of determinism at the atomic level.
My impression (also not a physicist) is that there’s no obvious connection between a wave function collapsing somewhere in the universe and your neurons churning through a decision about which door you’d rather walk through. Under Many Worlds, every quantum-possible universe exists, but that doesn’t mean that your experience of decision-making is equal-and-opposite distributed across those worlds. If you like the look of the right door better than the left door, then probably most of your selves will go through that door.
(If you’re interested in a fictional exploration of these issues, Ted Chiang’s Anxiety is the Dizziness of Freedom is excellent.)
fwiw, my concern isn’t premised on “all futures / choices being equally likely.”
I think the concern is closer to something like “some set of futures are going to happen (there’s some distribution of Everett branches that exists and can’t be altered from the inside), so there’s not really room to change the course of things from a zoomed-out, point-of-view-of-the-universe perspective.”
I think so? (I’m also lacking the relevant physics.)
From the explainer I linked to:
The explainer doesn’t seem to imply the choice is equivalent to a quantum split unless I’m missing something? I’ve had Jeff’s reservation every time I’ve heard this argument. It seems like it would just be a huge coincidence for our decisions to actually correspond to splits. Subjective senses of uncertainty may not equal actual lack of determinism at the atomic level.
My impression (also not a physicist) is that there’s no obvious connection between a wave function collapsing somewhere in the universe and your neurons churning through a decision about which door you’d rather walk through. Under Many Worlds, every quantum-possible universe exists, but that doesn’t mean that your experience of decision-making is equal-and-opposite distributed across those worlds. If you like the look of the right door better than the left door, then probably most of your selves will go through that door.
(If you’re interested in a fictional exploration of these issues, Ted Chiang’s Anxiety is the Dizziness of Freedom is excellent.)
fwiw, my concern isn’t premised on “all futures / choices being equally likely.”
I think the concern is closer to something like “some set of futures are going to happen (there’s some distribution of Everett branches that exists and can’t be altered from the inside), so there’s not really room to change the course of things from a zoomed-out, point-of-view-of-the-universe perspective.”
I’ll give the Chiang story a look, thanks!