3 ms·

Isn't a simpler explanation that we're just... wrong about what we're feeling? My thought about this is that the feeling of free choice that we have stems from

Isn't a simpler explanation that we're just... wrong about what we're feeling? My thought about this is that the feeling of free choice that we have stems from a form of irreducible epistemic uncertainty: we can't know what we are going to do before we do it, because our knowledge would influence our action. Furthermore, when choosing between A and B, we may use our self-concept to simulate our choices, meaning that by necessity our self-model is non-deterministic: it indeed performs several different choices during deliberation. I think our error is that we mistake epistemological uncertainty for metaphysical uncertainty, and the non-determinism of our self-model for the non-determinism of our real self.

meroes 5y ago
Absolutely, free will may be a feeling and largely due to incomplete knowledge and not fundamental. But is it the simpler explanation? That is hard to answer. On the one hand Many Worlds is "simple" and deterministic, on the other hand the complexity of the universe is so much greater. A stochastic model like GRW is also simple in the sense there is only one world, and all particles have a regular chance of random collapse. Also Many Words doesn't just provide the (classical picture)*(number of worlds), so it isn't even that "simple". There is nonlocal structure to the global wavefunction. The worlds don't split into any possible worlds; if one splits one way the others have to split into the other possible choices. These global correlations are nonlocal AFAIK - I know the MWI is nonlocal but I have a hard time understanding David Wallace, Lev Vaidman, and Tim Maudlin who all say it is nonlocal. The precise nature of the nonlocality is hard to understand (for me), but it is nonlocal!
- breuleux 5y ago
  My general philosophy about interpretations of quantum mechanics is that insofar that there is an infinity of possible interpretations that are all mathematically equivalent, the probability that we would think of, let alone find the correct one is for all intents and purposes zero. I don't see any objective criterion that would let us rank them either, so even though it's a fun debate, it is also a pointless one (as long as there are no experiments to differentiate them). > The worlds don't split into any possible worlds; if one splits one way the others have to split into the other possible choices. My (possibly flawed) understanding of MWI is that there isn't really any splitting. There is just a quantum superposition of all possible worlds, and the amplitude corresponding to each one fluctuates over time. A "split" from A to possibilities B and C would just correspond to the amplitude of A draining to 0, half going to B, the other half going to C, but the branches might have had nonzero amplitudes to begin with (they already existed, but now they are "stronger"). Different "branches" may also pour amplitude into the same other "branch" (i.e. they join rather than split). In other words, every moment of possible universe has always existed and will always exist, but over time they switch from "off" (amplitude 0) to various degrees of "on", or to off again, and so on, accordingly to the wavefunction. It's nonlocal in the same way that quantum entanglement is nonlocal in any interpretation, it's just that now we're working on the gargantuan quantum entanglement of every possible state of the entire universe. MWI is arguably the simplest interpretation from the standpoint of rule simplicity: it doesn't involve a notion of collapse, so it has less rules than other interpretations. It is less simple if you look at the sheer mass of what exists according to it, but I find that notion of simplicity less compelling than rule simplicity. Either way, I don't think it matters so I'm noncommittal.
  - meroes 5y ago
    > every moment of possible universe has always existed and will always exist, but over time they switch from "off" This also seems to imply the MWI forces us into block time, then having to recover the experience of time flowing for finite observers like us. The MWI-verse has always existed, as you say, so I'm having a hard time imagining what you mean by dynamical "switching", unless you mean the feeling/appearance of. It would have to be the appearance of something happening, an appearance of time flowing when it is block. I'm sure we can imagine MWI can explain how observers like us in the MW universe experience a flow of time. This still may be simple in the long run.
    - breuleux 5y ago
      Well, the amplitudes would change: all possible universes "exist", but their existence is not binary, it has a complex amplitude. And the norms of the amplitudes of all universes sum to one. So basically if you have three universes, at time t you might have A:0.5, B:0.25, C:0.25, and then at time t+1 you might have A:0.30, B:0.40, C:0.30. Thus the "flow" of time is really just the flow of amplitudes from certain branches to certain others. The idea that something does not "exist or not exist", but rather "exists at amplitude 0, amplitude 0.5, amplitude -i, etc." is kind of a mind screw, but that's the suggestion. This being said, there might be a steady state or fixed point where all amplitudes remain constant. Not sure how we could know if there is one or if we're in it, but that would be interesting.
  - tsimionescu 5y ago
    > MWI is arguably the simplest interpretation from the standpoint of rule simplicity: it doesn't involve a notion of collapse, so it has less rules than other interpretations. This isn't entriely true. MWI still needs to explain why the observed behavior of a measurement is non-linear. So, it comes with a rule about how to deduce the observed probabilities from the wave function amplitudes: you have to do the calculation in a single 'world', you can't do them for the entire wave function; and then the amplitudes give you some kind of count for each 'world', so that if we then perform an analysis on all observers in all worlds, the chance of us being one of the observers who measure state A is proportional to the amplitude. Even worse, the MWI needs to find or posit some way for the universe to choose, for each quantum measurement, a particular basis that gives rise to the many worlds - as that is also something missing from the Schrodinger equation. The CI has an advantage here, as the basis is explicitly chosen by the measurement device, whereas in MWI it has to be a fundamental property of the universe (this is usually suggested to happen through de coherence, that there is actually one unique 'right' basis, the one that is stable under de coherence effects, but this is not entirely satisfactory).

meroes 5y ago

Absolutely, free will may be a feeling and largely due to incomplete knowledge and not fundamental. But is it the simpler explanation? That is hard to answer. On the one hand Many Worlds is "simple" and deterministic, on the other hand the complexity of the universe is so much greater. A stochastic model like GRW is also simple in the sense there is only one world, and all particles have a regular chance of random collapse. Also Many Words doesn't just provide the (classical picture)*(number of worlds), so it isn't even that "simple". There is nonlocal structure to the global wavefunction. The worlds don't split into any possible worlds; if one splits one way the others have to split into the other possible choices. These global correlations are nonlocal AFAIK - I know the MWI is nonlocal but I have a hard time understanding David Wallace, Lev Vaidman, and Tim Maudlin who all say it is nonlocal. The precise nature of the nonlocality is hard to understand (for me), but it is nonlocal!

breuleux 5y ago
My general philosophy about interpretations of quantum mechanics is that insofar that there is an infinity of possible interpretations that are all mathematically equivalent, the probability that we would think of, let alone find the correct one is for all intents and purposes zero. I don't see any objective criterion that would let us rank them either, so even though it's a fun debate, it is also a pointless one (as long as there are no experiments to differentiate them). > The worlds don't split into any possible worlds; if one splits one way the others have to split into the other possible choices. My (possibly flawed) understanding of MWI is that there isn't really any splitting. There is just a quantum superposition of all possible worlds, and the amplitude corresponding to each one fluctuates over time. A "split" from A to possibilities B and C would just correspond to the amplitude of A draining to 0, half going to B, the other half going to C, but the branches might have had nonzero amplitudes to begin with (they already existed, but now they are "stronger"). Different "branches" may also pour amplitude into the same other "branch" (i.e. they join rather than split). In other words, every moment of possible universe has always existed and will always exist, but over time they switch from "off" (amplitude 0) to various degrees of "on", or to off again, and so on, accordingly to the wavefunction. It's nonlocal in the same way that quantum entanglement is nonlocal in any interpretation, it's just that now we're working on the gargantuan quantum entanglement of every possible state of the entire universe. MWI is arguably the simplest interpretation from the standpoint of rule simplicity: it doesn't involve a notion of collapse, so it has less rules than other interpretations. It is less simple if you look at the sheer mass of what exists according to it, but I find that notion of simplicity less compelling than rule simplicity. Either way, I don't think it matters so I'm noncommittal.
- meroes 5y ago
  > every moment of possible universe has always existed and will always exist, but over time they switch from "off" This also seems to imply the MWI forces us into block time, then having to recover the experience of time flowing for finite observers like us. The MWI-verse has always existed, as you say, so I'm having a hard time imagining what you mean by dynamical "switching", unless you mean the feeling/appearance of. It would have to be the appearance of something happening, an appearance of time flowing when it is block. I'm sure we can imagine MWI can explain how observers like us in the MW universe experience a flow of time. This still may be simple in the long run.
  - breuleux 5y ago
    Well, the amplitudes would change: all possible universes "exist", but their existence is not binary, it has a complex amplitude. And the norms of the amplitudes of all universes sum to one. So basically if you have three universes, at time t you might have A:0.5, B:0.25, C:0.25, and then at time t+1 you might have A:0.30, B:0.40, C:0.30. Thus the "flow" of time is really just the flow of amplitudes from certain branches to certain others. The idea that something does not "exist or not exist", but rather "exists at amplitude 0, amplitude 0.5, amplitude -i, etc." is kind of a mind screw, but that's the suggestion. This being said, there might be a steady state or fixed point where all amplitudes remain constant. Not sure how we could know if there is one or if we're in it, but that would be interesting.
- tsimionescu 5y ago
  > MWI is arguably the simplest interpretation from the standpoint of rule simplicity: it doesn't involve a notion of collapse, so it has less rules than other interpretations. This isn't entriely true. MWI still needs to explain why the observed behavior of a measurement is non-linear. So, it comes with a rule about how to deduce the observed probabilities from the wave function amplitudes: you have to do the calculation in a single 'world', you can't do them for the entire wave function; and then the amplitudes give you some kind of count for each 'world', so that if we then perform an analysis on all observers in all worlds, the chance of us being one of the observers who measure state A is proportional to the amplitude. Even worse, the MWI needs to find or posit some way for the universe to choose, for each quantum measurement, a particular basis that gives rise to the many worlds - as that is also something missing from the Schrodinger equation. The CI has an advantage here, as the basis is explicitly chosen by the measurement device, whereas in MWI it has to be a fundamental property of the universe (this is usually suggested to happen through de coherence, that there is actually one unique 'right' basis, the one that is stable under de coherence effects, but this is not entirely satisfactory).