I just looked up “many minds” and it’s a little bit like what I wrote here, but described differently in ways that I think I don’t like. (It’s possible that Wikipedia is not doing it justice, or that I’m misunderstanding it.) I think minds are what brains do, and I think brains are macroscopic systems that follow the laws of quantum mechanics just like everything else in the universe.
What property distinguished a universe where “Harry found himself in a tails branch” and a universe where “Harry found himself in a heads branch”?
Those both happen in the same universe. Those Harry’s both exist. Maybe you should put aside many-worlds and just think about Parfit’s teletransportation paradox. I think you’re assuming that “thread of subjective experience” is a coherent concept that satisfies all the intuitive properties that we feel like it should have, and I think that the teletransportation paradox is a good illustration that it’s not coherent at all, or at the very least, we should be extraordinarily cautious when making claims about the properties of this alleged thing you call a “thread of subjective experience” or “thread of consciousness”. (See also other Parfit thought experiments along the same lines.)
I don’t like the idea where we talk about what will happen to Harry, as if that has to have a unique answer. Instead I’d rather talk about Harry-moments, where there’s a Harry at a particular time doing particular things and full of memories of what happened in the past. Then there are future Harry-moments. We can go backwards in time from a Harry-moment to a unique (at any given time) past Harry-moment corresponding to it—after all, we can inspect the memories in future-Harry-moment’s head about what past-Harry was doing at that time (assuming there were no weird brain surgeries etc). But we can’t uniquely go in the forward direction: Who’s to say that multiple future-Harry-moments can’t hold true memories of the very same past-Harry-moment?
Here I am, right now, a Steve-moment. I have a lot of direct and indirect evidence of quantum interactions that have happened in the past or are happening right now, as imprinted on my memories, surroundings, and so on. And if you a priori picked some possible property of those interactions that (according to the Born rule) has 1-in-a-googol probability to occur in general, then I would be delighted to bet my life’s savings that this property is not true of my current observations and memories. Obviously that doesn’t mean that it’s literally impossible.
“Thread of subjective experience” was an aside (just one of the mechanisms that explains why we “find ourselves” in a world that behaves according to the Born rule), don’t focus too much on it.
The core question is which physical mechanism (everything should be physical, right?) ensures that you almost never will see a string of a billion tails after a billion quantum coin flips, while the universe contains a quantum branch with you looking in astonishment on a string with a billion tails. Why should you expect that it will almost certainly not happen, when there’s always a physical instance of you that will see it happened?
You’ll have 2^1000000000 branches with exactly the same amplitude. You’ll experience every one of them. Which physical mechanism will make it more likely for you to experience strings with roughly the same number of heads and tails?
In the Copenhagen interpretation it’s trivial: when the quantum coin flipper writes a result of the flip the universe somehow samples from a probability distribution and the rest is the plain old probability theory. You don’t expect to observe a string of a billion tails (or any other preselected string), because you who observes this string almost never exist.
I just looked up “many minds” and it’s a little bit like what I wrote here, but described differently in ways that I think I don’t like. (It’s possible that Wikipedia is not doing it justice, or that I’m misunderstanding it.) I think minds are what brains do, and I think brains are macroscopic systems that follow the laws of quantum mechanics just like everything else in the universe.
Those both happen in the same universe. Those Harry’s both exist. Maybe you should put aside many-worlds and just think about Parfit’s teletransportation paradox. I think you’re assuming that “thread of subjective experience” is a coherent concept that satisfies all the intuitive properties that we feel like it should have, and I think that the teletransportation paradox is a good illustration that it’s not coherent at all, or at the very least, we should be extraordinarily cautious when making claims about the properties of this alleged thing you call a “thread of subjective experience” or “thread of consciousness”. (See also other Parfit thought experiments along the same lines.)
I don’t like the idea where we talk about what will happen to Harry, as if that has to have a unique answer. Instead I’d rather talk about Harry-moments, where there’s a Harry at a particular time doing particular things and full of memories of what happened in the past. Then there are future Harry-moments. We can go backwards in time from a Harry-moment to a unique (at any given time) past Harry-moment corresponding to it—after all, we can inspect the memories in future-Harry-moment’s head about what past-Harry was doing at that time (assuming there were no weird brain surgeries etc). But we can’t uniquely go in the forward direction: Who’s to say that multiple future-Harry-moments can’t hold true memories of the very same past-Harry-moment?
Here I am, right now, a Steve-moment. I have a lot of direct and indirect evidence of quantum interactions that have happened in the past or are happening right now, as imprinted on my memories, surroundings, and so on. And if you a priori picked some possible property of those interactions that (according to the Born rule) has 1-in-a-googol probability to occur in general, then I would be delighted to bet my life’s savings that this property is not true of my current observations and memories. Obviously that doesn’t mean that it’s literally impossible.
“Thread of subjective experience” was an aside (just one of the mechanisms that explains why we “find ourselves” in a world that behaves according to the Born rule), don’t focus too much on it.
The core question is which physical mechanism (everything should be physical, right?) ensures that you almost never will see a string of a billion tails after a billion quantum coin flips, while the universe contains a quantum branch with you looking in astonishment on a string with a billion tails. Why should you expect that it will almost certainly not happen, when there’s always a physical instance of you that will see it happened?
You’ll have 2^1000000000 branches with exactly the same amplitude. You’ll experience every one of them. Which physical mechanism will make it more likely for you to experience strings with roughly the same number of heads and tails?
In the Copenhagen interpretation it’s trivial: when the quantum coin flipper writes a result of the flip the universe somehow samples from a probability distribution and the rest is the plain old probability theory. You don’t expect to observe a string of a billion tails (or any other preselected string), because you who observes this string almost never exist.
What happens in MWI?