8 ms·

To speed things up: http://constructortheory.org/what-is-constructor-theory/ http://constructortheory.org/what-is-constructor-theory/ This is what the video ta

To speed things up: http://constructortheory.org/what-is-constructor-theory/ http://constructortheory.org/what-is-constructor-theory/ This is what the video talks about. I don't like this video much. It's tedious and lengthly. Probably no reasonable human being would assume that Quantum Mechanic as we know it is the "holy grail" of physics. We came up with it within 100 years. Can we explain everything? Of course not. To me, the fact that we have the uncertainty principle and schroedingers cat already prove that we basically built our understanding of physics on the premise that we can never understand it. We were basically throwing the towel and saying "yeah this is it". Advances are made through measurement and verification. How do you understand something that you can't measure, because the measurement changes the system? It was pretty obvious to me when I studied physics that this is 100% not how the world works. It's a model, like everything else. In the model of quantum mechanics, which undoubtedly is one of the most impressive human achievements nonetheless, we have essentially complete uncertainty on the quantum scale. We can not peek beyond it and it doesn't give us any insights into how to peek beyond it. It is, in a way, the end of the line. And like any end of the line in science, it needs a radically different thought or model, to overcome. I always found it amusing how physicists, who really should know better, actually believe that quantum mechanics is how the world works and that this is it. I always was with Einstein in rejecting Quantum Theory. It's a nice model. But that's really all it is. A model. This is not how the world works and we have come to see its limitations. We need something better if we ever want to leave our solar system and colonize space. Even Einstein fell into the trap of thinking that Quantum Mechanics is more than a model. "God does not throw a dice". Probably he does not, but it's the best approximation we could come up with. He should have refuted it and looked for something better instead. Who knows where we would be now.

aeternum 6y ago
This idea seems similar to Wolfram's somewhat new hypergraph + rule idea: https://writings.stephenwolfram.com/2020/04/finally-we-may-have-a-path-to-the-fundamental-theory-of-physics-and-its-beautiful/ https://writings.stephenwolfram.com/2020/04/finally-we-may-h...
- quiescant_dodo 6y ago
  This is a fascinating read. Thanks for sharing.
warbaker 6y ago
You're familiar with Bell's Theorem, yes? QM puts significant constraints on any physical theory that might underlie it.
mrmonkeyman 6y ago
He tried. Many people tried.
wruza 6y ago
The uncertainty is not exclusive to QM and is a property of any ‘wavy’ system, it seems. It is inherent. Here is the example: https://m.youtube.com/watch?v=MBnnXbOM5S4 https://m.youtube.com/watch?v=MBnnXbOM5S4 — if you want to defeat QM, attack its wave-part. It would be nice to have much better (deterministic, measurable) physics, but some properties just emerge from a fundamental level and you can’t do much about it (monster group etc). Nature and maths don’t care about our confusion and convenience. >should have refuted it and looked for something better instead Afaik, the time when theories were driven by ideas is over. Today it’s petabytes of data that you can’t really argue with over a mailbox, only discuss. (I’m just a layman physicist with deep interest, but shallow understanding, so please don’t quote me on any of this)
simiones 6y ago
Honestly, seeing the high-level requirements for what constructor theory defines as Possible / Impossible, I mostly expect that it will have to conclude that many of the transformations that happen in QM are Impossible (a constructor can't be conceived that could achieve those tasks with arbitrary precision and reliability). Related to your observations, I believe you are absolutely right in that it's likely we've sort of reached the end of the road in exploring beyond the quantum scale with the current approach. I do believe there are some dangling threads that can be pulled to help guide some other directions - such as the measurement problem and the no-communication theorem. I also have some hope that computer theory may be able to shed some light - at the moment, we have a clear distinction between quantum algorithms and classical algorithms, but we don't know if they are fundamentally different or not. A discovery of how to efficiently compute quantum algorithms on classical computers (i.e. BQP = P or at least BQP = NP) would likely be a major insight into QM itself. Conversely, proof that quantum computers are fundamentally different from classical computers would also hopefully show WHY/HOW they are different and help in this area. Alternatively, if it turns out that quantum computers are in fact not physically realizable or require exponential memory or energy would essentially prove that physical reality does not obey some of the properties that make quantum computers (apparently) more powerful than classical computers.
scotty79 6y ago
Shrodinger cat is not a physical thing. It just comes from interpretation which has no mathematics behind it. There are many equivalent interpretations. And they are equivalent because none of them postulates any additional math to observe.
IIAOPSW 6y ago
Quantum mechanics is a deterministic theory. It does not have "complete uncertainty at the quantum scale". The probabilistic aspect only comes into play when you cast a quantum state down to a classical observable quantity like position or momentum. You may have missed the subtle but important aspect of the uncertainty principle. It is not the case that there is a true underlying value of position and momentum for which the error bars are limited by quirk of theory. It is more like you expect to be able to observe 2 bytes of position information and 2 bytes of momentum information but the underlying quantum state is defined by 2 bytes in total. The full 4 bytes cannot fit inside 2 bytes. You can have a state which encodes the 2 bytes of position information but no momentum information, a state which encodes 1 byte of each, a state which encodes 2 bytes of momentum information but no position information, and everything in between. The uncertainty principle is actually a non-existence principle. When the position information exists the momentum information isn't uncertain, it just outright doesn't exist.
- simiones 6y ago
  That is one interpretation, but the reality is that we do not know. In fact, what you are describing is the position known as anti-realism - that quantities that can't be measure are not real, a major feature of the Copenhagen interpretation. But in other theories (those termed "realist"), such as Pilot Wave or Superdeterminism, the uncertainty principle is exactly an artifact of measurement. A particle has an exact position, momentum, energy, spin etc, but they can't be reliably measured all at once. In the end, these are philosophical positions, outside of our current mathematical and physical tools. Perhaps in time we will be able to settle these questions, but for now there are no definitive answers.
  - lisper 6y ago
    > In the end, these are philosophical positions Not really. Realist theories are actually just rhetorical sleight-of-hand. Bohmian positions, for example, are supposedly "real" but they cannot actually be measured, and this inability to measure them is not a technological limit, it is an inherent part of the interpretation. Bohmians essentially take the randomness, hide it in the infinite digits of a real (no pun intended) number, call that number "the actual position of a particle" and claim that, because it's "the actual position of a particle" that it is somehow "real". Well, it's not real. You can't measure it. You've just hidden the randomness behind some clever rhetoric. > the reality is that we do not know Yes, we do. The Bell inequalities and concomitant experiments show that quantum randomness is fundamental. You can hide it or sweep it under the rug but you can't get rid of it because it's actually part of our reality.
eigenket 6y ago
People have already replied to a lot of you wrote here, so I just want to add that Einstein emphatically did not reject quantum theory. Indeed he is probably one of the people who could fairly be called the creator of quantum theory. What Einstein was rejecting with that quote is what we call the "Copenhagen Interpretation" of quantum theory. In my opinion he was quite right to do so, I do not know anyone in the quantum foundations community that takes Copenhagen very seriously any more. Einstein's qualms about Copenhagen lead the way to us understanding its flaws, and to people like John Bell putting us on a path to fixing some of those flaws. Einstein spent a lot of time looking for "something better" than Copenhagen, sadly he did not find it, but people who came later than him did (Everett, Bohm, the quantum Bayesianists etc). I'm going to slightly repeat what others have said here and talk about your issue with the uncertainty principle. Think about a wave travelling on the surface of an otherwise smooth swimming pool. The wave is an extended object, it is spread out. When we model the wave the fact that we don't assign it a perfectly precise "position" is a feature, not a bug of our model. Similarly I would argue that the uncertainty principle is not some barrier "blocking" us from seeing the true values of observables as we would like. It is a statement telling us that our mental model of things having a precise position and momentum at the same time is wrong, as wrong as trying to locate the wave at a precise position on the pool would be.
renox 6y ago
Strong assertions.. I think that you'd better study the EPR paradox (E as in Einstein), Bell's inequality https://en.wikipedia.org/wiki/Bell%27s_theorem https://en.wikipedia.org/wiki/Bell%27s_theorem and the Alan Aspect (and other) experiments. To summarize: reality isn't "local" even though we cannot send information faster than light..
- eigenket 6y ago
  There are (at least) two local, deterministic interpretations of quantum mechanics (many worlds and superdeterminism). You are correct that Bell-type experiments put very strong constraints on such theories. If your theory is local it is going to be very weird.
  - l33tman 6y ago
    This is not meant as a snarky comment - but I would be happy to hear how many worlds is a local theory (as I guess it isn't a fully operational theory in the sense that QM+Born rule is). Even if you assume the independent, local evolution of all "branches" of Psi, at some point you need to explain interference (as that is an observed phenomena in our real world) and the comparison of different swaths of Psi's is not a local operation. How is this handled in that interpretation?
    - eigenket 6y ago
      By local I mean local in the sense of special relativity. Stuff at a point in spacetime only affects stuff at that point and in its causal future. If you want to affect something somewhere else then you have to fire a light particle or whatever there. Interference between different "branches" of the wavefunction is local if you're comparing the value of the two branches at the same point(s). Edit: I should emphasise that interference is a completely local (in the sense I use it above) process in every interpretation of quantum mechanics I am aware of (even Copenhagen) generally the thing that makes quantum mechanics non-local in various interpretations is measurement.
      - 6y ago
l33tman 6y ago
You're treading down a well worn path here, Einstein was down this road as well as you note and got stuck there for the rest of his life. Everybody in the field would WELCOME something we can measure but can't explain with QM. But there isn't, and not due to lack of trying. Cosmology aside (difficult to measure) all the measurements of femtoscale interactions and condensed matter "constants" and their corresponding QM/QFT calculations that match to like 13-15 decimal places.. there are just incredibly massive chunks of evidence in favor of QM. It's just not a "first approximation" of reality that can be thrown out easily. Theorists and experimentalists in the field come up with new tests every year (they are my favorite papers to read!), so it's absolutely not like there is some inherent scare of not daring to contest it. It's just that you need experiments to contest well-established and working theories, you can't just go out and say "well, but I don't like it".. By the way as I'm sure you know if you studied this kind of physics, the "it doesn't give us any insights into how to peek beyond it" isn't really true, there are falsifiable assumptions that are tested and peeked at all the time - I'm thinking on the hidden variable theorems and validations. The theorems don't assume any specific theory (QM or a new one would do). That road is a nice one to casually drive down.
edna314 6y ago
> Probably no reasonable human being would assume that Quantum Mechanic as we know it is the "holy grail" of physics. Fully agreed. This, however, rests on the assumption that there is a 'holy grail' in physics (aka a theory of everything). It's a matter of taste, but I don't like that idea that there is a theory of everything because it doesn't seem reasonable that every last bit of our universe is explainable by a single theory. Why would that be? Seems like a conspiracy, if this was the case. To me, it's rather quite comforting to assume that there is something (be it the position and momentum of an electron) which we won't ever be able to understand because it just seams realistic. If this wasn't the case and we could show that there is a theory of everything I would immediately start my quest to find Morpheus to ask him to give me the right pill to wake up.
YeGoblynQueenne 6y ago
>> I always found it amusing how physicists, who really should know better, actually believe that quantum mechanics is how the world works and that this is it. Is this a reasonable stance to adopt? "All experts in a field disagree with me - how amusing". Amusing or not it suggests that perhaps you are missing something that those experts are aware of. >> We need something better if we ever want to leave our solar system and colonize space. The way I understand it -I am, myself, no expert in the matter- we could be colonising space right now, the challenges are primarily engineering and economic (it would cost too much to develop the necessary technology) but we are not really lacking fundamental knowledge of how to do it, e.g. generation ships could work for that purpose, in principle, but nobody is mad enough to build one, let alone ride it if one was built.

aeternum 6y ago

This idea seems similar to Wolfram's somewhat new hypergraph + rule idea: https://writings.stephenwolfram.com/2020/04/finally-we-may-have-a-path-to-the-fundamental-theory-of-physics-and-its-beautiful/ https://writings.stephenwolfram.com/2020/04/finally-we-may-h...

quiescant_dodo 6y ago
This is a fascinating read. Thanks for sharing.

warbaker 6y ago

You're familiar with Bell's Theorem, yes? QM puts significant constraints on any physical theory that might underlie it.

mrmonkeyman 6y ago

He tried. Many people tried.

wruza 6y ago

The uncertainty is not exclusive to QM and is a property of any ‘wavy’ system, it seems. It is inherent. Here is the example: https://m.youtube.com/watch?v=MBnnXbOM5S4 https://m.youtube.com/watch?v=MBnnXbOM5S4 — if you want to defeat QM, attack its wave-part. It would be nice to have much better (deterministic, measurable) physics, but some properties just emerge from a fundamental level and you can’t do much about it (monster group etc). Nature and maths don’t care about our confusion and convenience. >should have refuted it and looked for something better instead Afaik, the time when theories were driven by ideas is over. Today it’s petabytes of data that you can’t really argue with over a mailbox, only discuss. (I’m just a layman physicist with deep interest, but shallow understanding, so please don’t quote me on any of this)

simiones 6y ago

Honestly, seeing the high-level requirements for what constructor theory defines as Possible / Impossible, I mostly expect that it will have to conclude that many of the transformations that happen in QM are Impossible (a constructor can't be conceived that could achieve those tasks with arbitrary precision and reliability). Related to your observations, I believe you are absolutely right in that it's likely we've sort of reached the end of the road in exploring beyond the quantum scale with the current approach. I do believe there are some dangling threads that can be pulled to help guide some other directions - such as the measurement problem and the no-communication theorem. I also have some hope that computer theory may be able to shed some light - at the moment, we have a clear distinction between quantum algorithms and classical algorithms, but we don't know if they are fundamentally different or not. A discovery of how to efficiently compute quantum algorithms on classical computers (i.e. BQP = P or at least BQP = NP) would likely be a major insight into QM itself. Conversely, proof that quantum computers are fundamentally different from classical computers would also hopefully show WHY/HOW they are different and help in this area. Alternatively, if it turns out that quantum computers are in fact not physically realizable or require exponential memory or energy would essentially prove that physical reality does not obey some of the properties that make quantum computers (apparently) more powerful than classical computers.

scotty79 6y ago

Shrodinger cat is not a physical thing. It just comes from interpretation which has no mathematics behind it. There are many equivalent interpretations. And they are equivalent because none of them postulates any additional math to observe.

IIAOPSW 6y ago

Quantum mechanics is a deterministic theory. It does not have "complete uncertainty at the quantum scale". The probabilistic aspect only comes into play when you cast a quantum state down to a classical observable quantity like position or momentum. You may have missed the subtle but important aspect of the uncertainty principle. It is not the case that there is a true underlying value of position and momentum for which the error bars are limited by quirk of theory. It is more like you expect to be able to observe 2 bytes of position information and 2 bytes of momentum information but the underlying quantum state is defined by 2 bytes in total. The full 4 bytes cannot fit inside 2 bytes. You can have a state which encodes the 2 bytes of position information but no momentum information, a state which encodes 1 byte of each, a state which encodes 2 bytes of momentum information but no position information, and everything in between. The uncertainty principle is actually a non-existence principle. When the position information exists the momentum information isn't uncertain, it just outright doesn't exist.

simiones 6y ago
That is one interpretation, but the reality is that we do not know. In fact, what you are describing is the position known as anti-realism - that quantities that can't be measure are not real, a major feature of the Copenhagen interpretation. But in other theories (those termed "realist"), such as Pilot Wave or Superdeterminism, the uncertainty principle is exactly an artifact of measurement. A particle has an exact position, momentum, energy, spin etc, but they can't be reliably measured all at once. In the end, these are philosophical positions, outside of our current mathematical and physical tools. Perhaps in time we will be able to settle these questions, but for now there are no definitive answers.
- lisper 6y ago
  > In the end, these are philosophical positions Not really. Realist theories are actually just rhetorical sleight-of-hand. Bohmian positions, for example, are supposedly "real" but they cannot actually be measured, and this inability to measure them is not a technological limit, it is an inherent part of the interpretation. Bohmians essentially take the randomness, hide it in the infinite digits of a real (no pun intended) number, call that number "the actual position of a particle" and claim that, because it's "the actual position of a particle" that it is somehow "real". Well, it's not real. You can't measure it. You've just hidden the randomness behind some clever rhetoric. > the reality is that we do not know Yes, we do. The Bell inequalities and concomitant experiments show that quantum randomness is fundamental. You can hide it or sweep it under the rug but you can't get rid of it because it's actually part of our reality.

eigenket 6y ago

People have already replied to a lot of you wrote here, so I just want to add that Einstein emphatically did not reject quantum theory. Indeed he is probably one of the people who could fairly be called the creator of quantum theory. What Einstein was rejecting with that quote is what we call the "Copenhagen Interpretation" of quantum theory. In my opinion he was quite right to do so, I do not know anyone in the quantum foundations community that takes Copenhagen very seriously any more. Einstein's qualms about Copenhagen lead the way to us understanding its flaws, and to people like John Bell putting us on a path to fixing some of those flaws. Einstein spent a lot of time looking for "something better" than Copenhagen, sadly he did not find it, but people who came later than him did (Everett, Bohm, the quantum Bayesianists etc). I'm going to slightly repeat what others have said here and talk about your issue with the uncertainty principle. Think about a wave travelling on the surface of an otherwise smooth swimming pool. The wave is an extended object, it is spread out. When we model the wave the fact that we don't assign it a perfectly precise "position" is a feature, not a bug of our model. Similarly I would argue that the uncertainty principle is not some barrier "blocking" us from seeing the true values of observables as we would like. It is a statement telling us that our mental model of things having a precise position and momentum at the same time is wrong, as wrong as trying to locate the wave at a precise position on the pool would be.

renox 6y ago

Strong assertions.. I think that you'd better study the EPR paradox (E as in Einstein), Bell's inequality https://en.wikipedia.org/wiki/Bell%27s_theorem https://en.wikipedia.org/wiki/Bell%27s_theorem and the Alan Aspect (and other) experiments. To summarize: reality isn't "local" even though we cannot send information faster than light..

eigenket 6y ago
There are (at least) two local, deterministic interpretations of quantum mechanics (many worlds and superdeterminism). You are correct that Bell-type experiments put very strong constraints on such theories. If your theory is local it is going to be very weird.
- l33tman 6y ago
  This is not meant as a snarky comment - but I would be happy to hear how many worlds is a local theory (as I guess it isn't a fully operational theory in the sense that QM+Born rule is). Even if you assume the independent, local evolution of all "branches" of Psi, at some point you need to explain interference (as that is an observed phenomena in our real world) and the comparison of different swaths of Psi's is not a local operation. How is this handled in that interpretation?
  - eigenket 6y ago
    By local I mean local in the sense of special relativity. Stuff at a point in spacetime only affects stuff at that point and in its causal future. If you want to affect something somewhere else then you have to fire a light particle or whatever there. Interference between different "branches" of the wavefunction is local if you're comparing the value of the two branches at the same point(s). Edit: I should emphasise that interference is a completely local (in the sense I use it above) process in every interpretation of quantum mechanics I am aware of (even Copenhagen) generally the thing that makes quantum mechanics non-local in various interpretations is measurement.
    - 6y ago

l33tman 6y ago

You're treading down a well worn path here, Einstein was down this road as well as you note and got stuck there for the rest of his life. Everybody in the field would WELCOME something we can measure but can't explain with QM. But there isn't, and not due to lack of trying. Cosmology aside (difficult to measure) all the measurements of femtoscale interactions and condensed matter "constants" and their corresponding QM/QFT calculations that match to like 13-15 decimal places.. there are just incredibly massive chunks of evidence in favor of QM. It's just not a "first approximation" of reality that can be thrown out easily. Theorists and experimentalists in the field come up with new tests every year (they are my favorite papers to read!), so it's absolutely not like there is some inherent scare of not daring to contest it. It's just that you need experiments to contest well-established and working theories, you can't just go out and say "well, but I don't like it".. By the way as I'm sure you know if you studied this kind of physics, the "it doesn't give us any insights into how to peek beyond it" isn't really true, there are falsifiable assumptions that are tested and peeked at all the time - I'm thinking on the hidden variable theorems and validations. The theorems don't assume any specific theory (QM or a new one would do). That road is a nice one to casually drive down.

edna314 6y ago

> Probably no reasonable human being would assume that Quantum Mechanic as we know it is the "holy grail" of physics. Fully agreed. This, however, rests on the assumption that there is a 'holy grail' in physics (aka a theory of everything). It's a matter of taste, but I don't like that idea that there is a theory of everything because it doesn't seem reasonable that every last bit of our universe is explainable by a single theory. Why would that be? Seems like a conspiracy, if this was the case. To me, it's rather quite comforting to assume that there is something (be it the position and momentum of an electron) which we won't ever be able to understand because it just seams realistic. If this wasn't the case and we could show that there is a theory of everything I would immediately start my quest to find Morpheus to ask him to give me the right pill to wake up.

YeGoblynQueenne 6y ago

>> I always found it amusing how physicists, who really should know better, actually believe that quantum mechanics is how the world works and that this is it. Is this a reasonable stance to adopt? "All experts in a field disagree with me - how amusing". Amusing or not it suggests that perhaps you are missing something that those experts are aware of. >> We need something better if we ever want to leave our solar system and colonize space. The way I understand it -I am, myself, no expert in the matter- we could be colonising space right now, the challenges are primarily engineering and economic (it would cost too much to develop the necessary technology) but we are not really lacking fundamental knowledge of how to do it, e.g. generation ships could work for that purpose, in principle, but nobody is mad enough to build one, let alone ride it if one was built.