In general I agree, and of course Copenhagen is nonsense, but I think you privilege the hypothesis of Many-Worlds over Bohm. You see, Bohm has an explanation for the Born probabilities—they are a stable equilibrium state called, appropriately, “quantum equilibrium”. So there are not even any open questions.
And yes, Bohm is non-local, which you could say is a problem… or you could say it explains why quantum mechanics is different from classical mechanics. (Obviously no quantum theory is going to satisfy all our classical intuitions, or it wouldn’t be a quantum theory at all!)
It doesn’t fit with general relativity, you say? Yes, because none of them do. Quantum gravity doesn’t… work, not with our current formalisms. This is the central problem of modern physics (that and dark energy, which most physicists think is related somehow).
And yes, Bohm is non-local, which you could say is a problem… or you could say it explains why quantum mechanics is different from classical mechanics.
I’m not saying the Bohm interpretation is wrong (because I’m too inexperienced in the field to say), but I do not see how the above statement can be used to privilege Bohm over any other theory. If anything, shouldn’t its non-locality lower our priors on its correctness?
Interpretations can’t be wrong, otherwise they would not be interpretations. They also can’t be right, for the same reason. Here I define”wrong” in the natural sciences sense, “failed an experimental test”. And that’s the only definition that matters when talking about QM (which is a natural science), as opposed to morality and stuff.
I believe the traditional example is a spacecraft passing over the cosmological horizon. We cannot observe this spacecraft, so the belief “things passing over the cosmological horizon cease to exist” cannot be experimentally proved or disproved. And yet, if there are large numbers of people on such a craft, their continued survival might mater a great deal to us. If we believe they will die, we will choose not to send them—which might impose heavy costs due to i.e. overpopulation.
The analogy to many-worlds seems obvious—if true, it would mean the existence of people we cannot experimentally verify. This could have implications for, say, the value of creating new minds, because they’ll already exist somewhere else.
The analogy is hand-waving. If the spacecraft has gone over the cosmological horizon, how did you ever conclude that it exists in the first place? Such a conclusion would only be possible if you observed the spacecraft before it crossed over. In other words, it passed an experimental test.
I suppose I would not be failing an empirical test, but I would be going against the well established law of conservation of mass and energy, and we can conclude I am wrong with >99% certainty.
To prevent us from getting too hooked on the analogy and back to my original question, if there is a theory (Bohm) that cannot pass or fail an experimental test but does go against a well established principle (locality), why should we give it a second glance? (Again, not a rhetorical question.)
I suppose I would not be failing an empirical test, but I would be going against the well established law of conservation of mass and energy, and we can conclude I am wrong with >99% certainty.
Precisely my point. The Law Of Conservation Of Energy is only well-established—empirically speaking—to hold within the observable universe. The Law Of Conservation Of Energy That I Can See is, of course, more complex, and there’s no reason to privileged the hypothesis—as long as you have some way of assigning probabilities to things you can’t observe.
To prevent us from getting too hooked on the analogy and back to my original question, if there is a theory (Bohm) that cannot pass or fail an experimental test but does go against a well established principle (locality), why should we give it a second glance? (Again, not a rhetorical question.)
Well, the Official LW Position (as endorsed by Eliezer Yudkowsky) is that you shouldn’t. And, honestly, that makes a lot of sense. Some people, however, are determined to argue that the whole question is somehow meaningless or impossible to answer.
I believe the traditional example is a spacecraft passing over the cosmological horizon. We cannot observe this spacecraft, so the belief “things passing over the cosmological horizon cease to exist” cannot be experimentally proved or disproved.
However, the conclusion that they don’t subjectively cease to exist after we can no longer communicate with them follows unambiguously from the well-tested models of physics and cosmology. It does not require any strong extra assumptions, only some very weak ones, like that we are not in a cosmic-scale Truman show, or that the Copernican Principle holds.
By comparison, many-worlds is a strong extra assumption which has never been tested and is currently not testable (no, despite the popular misconception here, it does not follow from “just” the Schrodinger equation).
The “Truman Show Hypothesis” may violate the Copernican Principle, but it cannot be experimentally disproved.
I am not using this to argue for Many-Worlds; merely that we should care if Many-Worlds is true.
EDIT: A similar analogy would be that the ship turns into pure utilitronium, rather than vanishing. This might be a better analogy for the MWI for you.
Interpretations can’t be wrong, otherwise they would not be interpretations. They also can’t be right, for the same reason.
Two questions. First, is that true as a matter of how you define ‘interpretation’, or is it true as a matter of subsequent fact? Second, do you mean to say that interpretations haven’t yet passed or failed an experimental test?; or do you mean to say that interpretations can never pass or fail an experimental test?
The ‘haven’t yet’ criterion is weakly true of ‘interpretations’ in the relevant QM context, though all the interpretations of interest here have been verified relative to empirically false models; they just haven’t been verified relative to one another. But the ‘can never’ criterion is clearly false of some of the ‘interpretations’ we’re talking about, and only contingently and ambiguously true of any of them. Whether these models will ever be empirically testable is itself an empirical question.
Here I define”wrong” in the natural sciences sense, “failed an experimental test”. And that’s the only definition that matters when talking about QM (which is a natural science)
What are you building into ‘right’/‘wrong’ here? That is, why does your assertion have more semantic content than if you’d skipped the ‘right’/‘wrong’ assertion and just said ‘The Bohm interpretation hasn’t passed an experimental test yet. Bye now!’? Certainly if you mean to suggest that scientific models cannot have merits or dismerits aside from experimental verification/falsification, then this is wrong. Scientific models can be overly vague, or ambiguous, or internally inconsistent, or overly complex or inelegant, or unexplanatory, or gerrymandered, or ad-hoc, or unverifiable, or unfalsifiable, or historically (as opposed to experimentally) false. All of those are faults in their own right—and, often, they are Bayesianly relevant faults, faults that should impact our credence in the model.
But the ‘can never’ criterion is clearly false of some of the ‘interpretations’ we’re talking about, and only contingently and ambiguously true of any of them.
Interpretations are designed to give the same predictions as can be inferred from a no-interpretation math, otherwise they would be called theories.
What are you building into ‘right’/‘wrong’ here?
Experimentally testable new predictions. No more, no less.
Interpretations are designed to give the same predictions as can be inferred from a no-interpretation math, otherwise they would be called theories.
This is empirically false, as a statement about how scientific discourse works. Compare string theory, which is frequently labeled a ‘theory’ (or family of theories) even though it has far more difficult-to-observe posits (one-dimensional strings!) than most (perhaps all) of the mainstream QM ‘interpretations’. See also falsified QM interpretations.
Perhaps a more model-theoretic approach would be appropriate here; clearly QM interpretations can vary quite a bit in their verifiability/falsifiability, so what distinguishes them from other theories may be that they specify the meanings of the terms in the QM formalism. On this view, ‘interpretations’ may add real content and predictions to a set of statements, provided that in the process they also fix the semantics of a large portion of the statements. After all, the problem with QM is not merely that we aren’t clear on the invisible metaphysics secretly underwriting and accounting for our experiences; we aren’t even clear on the phenomenology (appearances) or ontology (observable posits) of the theory, treated as mere formalism.
Interpretations are designed to give the same predictions as can be inferred from a no-interpretation math, otherwise they would be called theories.
This isn’t necessarily true. Consider that the GRW interpretation has been pretty much falsified by Van Harlingen’s work at UIUC (macroscopic current superposition in SQUIDs). Most of the interpretations rely on different postulates than traditional Copenhagen quantum so there can be (and generally are) differences. However, to date, most of those differences aren’t measurable.
Similarly, we call many-worlds an “interpretation” even though no one has figured out how to actually make predictions with it. The difference between “interpretation” and “theory” is a bit loose.
This isn’t necessarily true. Consider that the GRW interpretation has been pretty much falsified by Van Harlingen’s work at UIUC (macroscopic current superposition in SQUIDs).
I am not familiar with the GRW theory, but, like most other objective collapse models and unlike [the lowest common denominator] Copenhagen, it appears to be more than an interpretation, so no wonder that it can be falsified.
Anyway, my definition of an interpretation is “same math, same predictions, different invisible underlying ontology”. If your definition is different, feel free to state it.
Almost all “interpretations” (using the word as used in the literature) of quantum mechanics use different axioms, and its a mathematical question as to whether or not the theories make the same predictions. Many stochastic “interpretations” modify the Schroedinger equation, for instance. Even many-worlds can’t be proven as an interpretation using your definition (no one has shown it actually leads to the same predictions as Copenhagen).
Its an unfortunate artifact of the literature on various approaches quantum mechanics that the words interpretation and theory often over-load each other, but its the reality we live in.
If that’s your definition, then it’s an empirical question whether a given model is an interpretation, because it’s often contingent and difficult-to-demonstrate that a given ontology is necessarily ‘invisible’, as opposed to ‘potentially-testable-but-as-yet-untested’. Impossibility proofs about future scientific experiments are no easy task. So we can only speculate about whether Many Worlds, Bohmian Mechanics, Collapse theories, etc. are ‘interpretations’ in your sense.
(And by ‘invisible’ I gather you mean ‘empirically equivalent to a certain set of rivals’—so whether something’s an interpretation is always relative to other models, the real predicate is interpretation-compared-to-x.)
In general I agree, and of course Copenhagen is nonsense, but I think you privilege the hypothesis of Many-Worlds over Bohm. You see, Bohm has an explanation for the Born probabilities—they are a stable equilibrium state called, appropriately, “quantum equilibrium”. So there are not even any open questions.
And yes, Bohm is non-local, which you could say is a problem… or you could say it explains why quantum mechanics is different from classical mechanics. (Obviously no quantum theory is going to satisfy all our classical intuitions, or it wouldn’t be a quantum theory at all!)
It doesn’t fit with general relativity, you say? Yes, because none of them do. Quantum gravity doesn’t… work, not with our current formalisms. This is the central problem of modern physics (that and dark energy, which most physicists think is related somehow).
I’m not saying the Bohm interpretation is wrong (because I’m too inexperienced in the field to say), butI do not see how the above statement can be used to privilege Bohm over any other theory. If anything, shouldn’t its non-locality lower our priors on its correctness?Interpretations can’t be wrong, otherwise they would not be interpretations. They also can’t be right, for the same reason. Here I define”wrong” in the natural sciences sense, “failed an experimental test”. And that’s the only definition that matters when talking about QM (which is a natural science), as opposed to morality and stuff.
Redefining an existing word to make an unrelated point is widely considered not clever.
If interpretations cannot pass or fail an experimental test, what purpose do they serve?
(Not a rhetorical question; genuinely curious.)
They give you an excuse to not bite the bullet and accept the math as the way the universe actually is.
You might value something you can’t always see.
That didn’t really answer the question. Can you give a context-specific answer?
I believe the traditional example is a spacecraft passing over the cosmological horizon. We cannot observe this spacecraft, so the belief “things passing over the cosmological horizon cease to exist” cannot be experimentally proved or disproved. And yet, if there are large numbers of people on such a craft, their continued survival might mater a great deal to us. If we believe they will die, we will choose not to send them—which might impose heavy costs due to i.e. overpopulation.
The analogy to many-worlds seems obvious—if true, it would mean the existence of people we cannot experimentally verify. This could have implications for, say, the value of creating new minds, because they’ll already exist somewhere else.
The analogy is hand-waving. If the spacecraft has gone over the cosmological horizon, how did you ever conclude that it exists in the first place? Such a conclusion would only be possible if you observed the spacecraft before it crossed over. In other words, it passed an experimental test.
You have a spaceship. You believe that it will cease to exist if it passes the cosmological horizon. What empirical test are you failing?
I suppose I would not be failing an empirical test, but I would be going against the well established law of conservation of mass and energy, and we can conclude I am wrong with >99% certainty.
To prevent us from getting too hooked on the analogy and back to my original question, if there is a theory (Bohm) that cannot pass or fail an experimental test but does go against a well established principle (locality), why should we give it a second glance? (Again, not a rhetorical question.)
Precisely my point. The Law Of Conservation Of Energy is only well-established—empirically speaking—to hold within the observable universe. The Law Of Conservation Of Energy That I Can See is, of course, more complex, and there’s no reason to privileged the hypothesis—as long as you have some way of assigning probabilities to things you can’t observe.
Well, the Official LW Position (as endorsed by Eliezer Yudkowsky) is that you shouldn’t. And, honestly, that makes a lot of sense. Some people, however, are determined to argue that the whole question is somehow meaningless or impossible to answer.
However, the conclusion that they don’t subjectively cease to exist after we can no longer communicate with them follows unambiguously from the well-tested models of physics and cosmology. It does not require any strong extra assumptions, only some very weak ones, like that we are not in a cosmic-scale Truman show, or that the Copernican Principle holds.
By comparison, many-worlds is a strong extra assumption which has never been tested and is currently not testable (no, despite the popular misconception here, it does not follow from “just” the Schrodinger equation).
The “Truman Show Hypothesis” may violate the Copernican Principle, but it cannot be experimentally disproved.
I am not using this to argue for Many-Worlds; merely that we should care if Many-Worlds is true.
EDIT: A similar analogy would be that the ship turns into pure utilitronium, rather than vanishing. This might be a better analogy for the MWI for you.
Two questions. First, is that true as a matter of how you define ‘interpretation’, or is it true as a matter of subsequent fact? Second, do you mean to say that interpretations haven’t yet passed or failed an experimental test?; or do you mean to say that interpretations can never pass or fail an experimental test?
The ‘haven’t yet’ criterion is weakly true of ‘interpretations’ in the relevant QM context, though all the interpretations of interest here have been verified relative to empirically false models; they just haven’t been verified relative to one another. But the ‘can never’ criterion is clearly false of some of the ‘interpretations’ we’re talking about, and only contingently and ambiguously true of any of them. Whether these models will ever be empirically testable is itself an empirical question.
What are you building into ‘right’/‘wrong’ here? That is, why does your assertion have more semantic content than if you’d skipped the ‘right’/‘wrong’ assertion and just said ‘The Bohm interpretation hasn’t passed an experimental test yet. Bye now!’? Certainly if you mean to suggest that scientific models cannot have merits or dismerits aside from experimental verification/falsification, then this is wrong. Scientific models can be overly vague, or ambiguous, or internally inconsistent, or overly complex or inelegant, or unexplanatory, or gerrymandered, or ad-hoc, or unverifiable, or unfalsifiable, or historically (as opposed to experimentally) false. All of those are faults in their own right—and, often, they are Bayesianly relevant faults, faults that should impact our credence in the model.
Interpretations are designed to give the same predictions as can be inferred from a no-interpretation math, otherwise they would be called theories.
Experimentally testable new predictions. No more, no less.
This is empirically false, as a statement about how scientific discourse works. Compare string theory, which is frequently labeled a ‘theory’ (or family of theories) even though it has far more difficult-to-observe posits (one-dimensional strings!) than most (perhaps all) of the mainstream QM ‘interpretations’. See also falsified QM interpretations.
Perhaps a more model-theoretic approach would be appropriate here; clearly QM interpretations can vary quite a bit in their verifiability/falsifiability, so what distinguishes them from other theories may be that they specify the meanings of the terms in the QM formalism. On this view, ‘interpretations’ may add real content and predictions to a set of statements, provided that in the process they also fix the semantics of a large portion of the statements. After all, the problem with QM is not merely that we aren’t clear on the invisible metaphysics secretly underwriting and accounting for our experiences; we aren’t even clear on the phenomenology (appearances) or ontology (observable posits) of the theory, treated as mere formalism.
This isn’t necessarily true. Consider that the GRW interpretation has been pretty much falsified by Van Harlingen’s work at UIUC (macroscopic current superposition in SQUIDs). Most of the interpretations rely on different postulates than traditional Copenhagen quantum so there can be (and generally are) differences. However, to date, most of those differences aren’t measurable.
Similarly, we call many-worlds an “interpretation” even though no one has figured out how to actually make predictions with it. The difference between “interpretation” and “theory” is a bit loose.
I am not familiar with the GRW theory, but, like most other objective collapse models and unlike [the lowest common denominator] Copenhagen, it appears to be more than an interpretation, so no wonder that it can be falsified.
Anyway, my definition of an interpretation is “same math, same predictions, different invisible underlying ontology”. If your definition is different, feel free to state it.
Almost all “interpretations” (using the word as used in the literature) of quantum mechanics use different axioms, and its a mathematical question as to whether or not the theories make the same predictions. Many stochastic “interpretations” modify the Schroedinger equation, for instance. Even many-worlds can’t be proven as an interpretation using your definition (no one has shown it actually leads to the same predictions as Copenhagen).
Its an unfortunate artifact of the literature on various approaches quantum mechanics that the words interpretation and theory often over-load each other, but its the reality we live in.
If that’s your definition, then it’s an empirical question whether a given model is an interpretation, because it’s often contingent and difficult-to-demonstrate that a given ontology is necessarily ‘invisible’, as opposed to ‘potentially-testable-but-as-yet-untested’. Impossibility proofs about future scientific experiments are no easy task. So we can only speculate about whether Many Worlds, Bohmian Mechanics, Collapse theories, etc. are ‘interpretations’ in your sense.
(And by ‘invisible’ I gather you mean ‘empirically equivalent to a certain set of rivals’—so whether something’s an interpretation is always relative to other models, the real predicate is interpretation-compared-to-x.)