4 ms·

MWI seems more elegant than Copenhagen in many formulations because the problem of the relative magnitudes of the worlds is swept under the rug. If I perform a

MWI seems more elegant than Copenhagen in many formulations because the problem of the relative magnitudes of the worlds is swept under the rug. If I perform a quantum coin-flip with 2/3 possibility of heads, then it creates two worlds - but I end up in one of them twice as often - why? The only solutions I've seen to preserve the relative probabilities are: 1) sufficiently unlikely worlds sometimes just disappear, or 2) some kind of appeal to consciousness. These are at least as ad-hoc and hand-wavy as waveform collapse.

spiritcat 8y ago
Or it actually creates three worlds, two heads worlds and one tails.
- tbabb 8y ago
  Or an infinity of worlds, with two thirds of them with heads, and one third with tails.
- Jweb_Guru 8y ago
  Being able to count worlds in the manner you describe is apparently not easy to justify. If I recall correctly, this is actually a pretty thorny epistemological problem with the theory. IIRC the current response among Many Worlds people is that either (1) it doesn't really matter because there is no reason to believe that probabilities are "real" in the first place, or (2) attempting to show that if you did insist on finding a metric that looked like probability, it would provably have to be the Born probability (see https://arxiv.org/abs/1405.7577 https://arxiv.org/abs/1405.7577). All this stuff is way over my head so I have no way of evaluating whether it's persuasive or not, but it does at least seem to be contentious among physicists.
int_19h 8y ago
> If I perform a quantum coin-flip with 2/3 possibility of heads, then it creates two worlds - but I end up in one of them twice as often - why? This question is impossible to answer until you unambiguously define "I" and "end up" first. My answer is that there's no singular you. There's one you for each of the worlds, just as there's one coin for each of the worlds. The only difference is that the coin doesn't wonder about its "other selves", because it doesn't have the concept of self. Humans do have one, but we have no reason to believe that it is correct or meaningful in this context.

spiritcat 8y ago

Or it actually creates three worlds, two heads worlds and one tails.

tbabb 8y ago
Or an infinity of worlds, with two thirds of them with heads, and one third with tails.
Jweb_Guru 8y ago
Being able to count worlds in the manner you describe is apparently not easy to justify. If I recall correctly, this is actually a pretty thorny epistemological problem with the theory. IIRC the current response among Many Worlds people is that either (1) it doesn't really matter because there is no reason to believe that probabilities are "real" in the first place, or (2) attempting to show that if you did insist on finding a metric that looked like probability, it would provably have to be the Born probability (see https://arxiv.org/abs/1405.7577 https://arxiv.org/abs/1405.7577). All this stuff is way over my head so I have no way of evaluating whether it's persuasive or not, but it does at least seem to be contentious among physicists.

int_19h 8y ago

> If I perform a quantum coin-flip with 2/3 possibility of heads, then it creates two worlds - but I end up in one of them twice as often - why? This question is impossible to answer until you unambiguously define "I" and "end up" first. My answer is that there's no singular you. There's one you for each of the worlds, just as there's one coin for each of the worlds. The only difference is that the coin doesn't wonder about its "other selves", because it doesn't have the concept of self. Humans do have one, but we have no reason to believe that it is correct or meaningful in this context.