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There’s a strong bias toward things that are model-able in neuroscience. The role of microtubules, for example, are mostly ignored even though they may explain

There’s a strong bias toward things that are model-able in neuroscience. The role of microtubules, for example, are mostly ignored even though they may explain the complexity of cognition displayed by relatively “simple” brains.

mikewarot 5y ago
Fringe Tangent: It's possible those microtubules in our brains are 1 dimensional superconductors, and thus might be capable of holding Qubits. We might have quantum memory. https://arxiv.org/ftp/arxiv/papers/1812/1812.05602.pdf https://arxiv.org/ftp/arxiv/papers/1812/1812.05602.pdf
- airstrike 5y ago
  This is why I come to HN daily. Thanks for the very interesting read.
- tsimionescu 5y ago
  That's still extremely unlikely given all we know about quantum computers so far, and about biology. It's also important to note that quantum computers are just faster classical computers, they are still Turing machines. Many people who are looking for some non-computable element of consciousness in quantum effects in microtubules seem to forget that.
  - mikewarot 5y ago
    Quantum computers are not Turing machines as far a I know. They can encode exponentially many states simultaneously, and are non-deterministic.
    - tsimionescu 5y ago
      You can simulate any quantum computer on a Turing machine, though it generally takes exponentially more time than with a real QC. Whether this means they are the same thing or not is a matter of semantics. But what is clear is that there is no computation that can be done on a QC that can't be done on a TM. The role of non-determinism in computation is more debatable. There is even a notable MIT professor (who coined the term Actor model) who claims that real computers, like the Android phone I'm writing this on, are in fact not Turing machines, because of non-determinism / parallelism. He also claims that Godel's incompleteness theorem doesn't apply to actual mathematics, so I would take his words with a huge spoonful of salt.
    - smegger001 5y ago
      they are they just dont work in binary bits they work with qbits which simply have behavior rules diffrent from digital but can be simulated by one just inefficiently. much like a binary computer can be approximated by a balanced trianay computer or analog computer or by pumps valves and flowing water like in MONIAC. they are all turring complete and can simulate each other just not efficiently. they dont have any magical logic gates they are just able to do a task that would need require lot of time or many parrelel computaions or both in less time because a single qbit is in super position of 1 and 0 simaltaniously and we can do mathmatical operations on it without collapsing the superposition until we have observed it. to simulate this on a traditional computer you would need to run it for each 2 time per bit. so for a 8 bit key for example you would need to run the same operation 256 times 65536 for a 16 bit key and 4,294,967,296 for a 32 bit. so in essence quantum computation just lets you cheat on massively parallel processes but is not a hyper-turring machine or a turring oracle. in fact there are many algorithms that you get no gain from using qubit other than i higher energy bill
      - smegger001 5y ago
        not sure why I am being down voted here perhaps someone needs to do some reading https://en.wikipedia.org/wiki/Quantum_computing#Computability_theory https://en.wikipedia.org/wiki/Quantum_computing#Computabilit... https://www.smbc-comics.com/comic/the-talk-3 https://www.smbc-comics.com/comic/the-talk-3
    - astrange 5y ago
      They are not computably non-deterministic, so they are still Turing machines with a random number generator attached. Qubits aren't magic either and the amount of data they can store is well known, it's just a complex bit instead of a real one.
      - tsimionescu 5y ago
        > they are still Turing machines with a random number generator attached It's important to note that probabilistic Turing machines are different from quantum Turing machines in terms of efficiency, as far as it is known today. But still, that doesn't change the fact that they can (inefficiently) simulate each other.
  - IIAOPSW 5y ago
    quantum computers are not just faster classical computers. Quantum algorithms have no classical counterpart. In fact the literal clock speed per quantum computation may be slower but the computation will still get done faster overall.
    - Robotbeat 5y ago
      But there’s no computation a quantum computer can do that a classical computer can’t. In that sense, it’s still a Turing machine. It can do some class of computation faster (in principle).
      - throwaway3699 5y ago
        If we want to reach AGI within the lifetime of the universe, and quantum effects are required for consciousness [within the lifetime etc...], it stands to reason we'd need quantum computers.
        tsimionescu 5y ago
        Yes, that is true, at least as far as we know today (it's not yet mathematically proven that quantum computers can't be efficiently simulated by probabilistic classical computers, even though we are almost certain of this).
      - hau 5y ago
        Richard Feynman describes such computation, that produces incorrect results on classic computer and correct one on quantum in "Simulating Physics with Computers"[0]. He follows one physical experiment detailing every step from start to finish and how it converges to incorrect result on classical computer. [0] - https://doi.org/10.1007/BF02650179 https://doi.org/10.1007/BF02650179
        tsimionescu 5y ago
        Thank you for the link! I have also found a free version for anyone else interested: http://physics.whu.edu.cn/dfiles/wenjian/1_00_QIC_Feynman.pdf http://physics.whu.edu.cn/dfiles/wenjian/1_00_QIC_Feynman.pd... However, Feynman does not claim what you say he claims. His whole article is about efficiently simulating QM on a classical computer, and he shows that is not possible given what we understand of quantum probability today, at least (he does this by explicitly asking for a computer which does not grow exponentially in size with the size of the physical system it wants to simulate). In modern CS terms, what he is discussing is whether the complexity classes BPP and BQP are equal or not (as far as we know today, just as he claims, BPP seems to be a smaller subset of BQP, but this is not proven). This is all perfectly in line with my claim, and is in fact explicitly there in Feynman's paper: a classical computer can perfectly simulate a quantum system/computer, but requires exponential time/space to do so (as far as we know).
- mikewarot 5y ago
  If (a huge if) our memories are stored in qubits, a sufficiently strong magnetic pulse (one much larger than found in an MRI) might be able to erase our brains. This also has interesting (morbid?) implications for how long our memories last after death.
seg_lol 5y ago
Reverse lamp post? We don't routinely take MRIs because of false positives, meaning we might have more questions than answers so we won't ask. Seems like neuroscience is still in the phase of reducing misunderstanding.
mr_toad 5y ago
Microtubules are found in all eukaryotic cells. Even single celled organisms. If microtubules are responsible for cognition, what are brains for, and why aren’t amoeba intelligent?
- kortex 5y ago
  Have you ever watched an amoeba do its thing? I wouldn't call it cognition, but its behavior is remarkable for something with no neurons. In fact microtubules are the exact structure posited to be responsible for where and how amoebas move their pseudopods. https://pubmed.ncbi.nlm.nih.gov/7983169/ https://pubmed.ncbi.nlm.nih.gov/7983169/
- procgen 5y ago
  Amoebas are intelligent. All living things are intelligent.

mikewarot 5y ago

Fringe Tangent: It's possible those microtubules in our brains are 1 dimensional superconductors, and thus might be capable of holding Qubits. We might have quantum memory. https://arxiv.org/ftp/arxiv/papers/1812/1812.05602.pdf https://arxiv.org/ftp/arxiv/papers/1812/1812.05602.pdf

airstrike 5y ago
This is why I come to HN daily. Thanks for the very interesting read.
tsimionescu 5y ago
That's still extremely unlikely given all we know about quantum computers so far, and about biology. It's also important to note that quantum computers are just faster classical computers, they are still Turing machines. Many people who are looking for some non-computable element of consciousness in quantum effects in microtubules seem to forget that.
- mikewarot 5y ago
  Quantum computers are not Turing machines as far a I know. They can encode exponentially many states simultaneously, and are non-deterministic.
  - tsimionescu 5y ago
    You can simulate any quantum computer on a Turing machine, though it generally takes exponentially more time than with a real QC. Whether this means they are the same thing or not is a matter of semantics. But what is clear is that there is no computation that can be done on a QC that can't be done on a TM. The role of non-determinism in computation is more debatable. There is even a notable MIT professor (who coined the term Actor model) who claims that real computers, like the Android phone I'm writing this on, are in fact not Turing machines, because of non-determinism / parallelism. He also claims that Godel's incompleteness theorem doesn't apply to actual mathematics, so I would take his words with a huge spoonful of salt.
  - smegger001 5y ago
    they are they just dont work in binary bits they work with qbits which simply have behavior rules diffrent from digital but can be simulated by one just inefficiently. much like a binary computer can be approximated by a balanced trianay computer or analog computer or by pumps valves and flowing water like in MONIAC. they are all turring complete and can simulate each other just not efficiently. they dont have any magical logic gates they are just able to do a task that would need require lot of time or many parrelel computaions or both in less time because a single qbit is in super position of 1 and 0 simaltaniously and we can do mathmatical operations on it without collapsing the superposition until we have observed it. to simulate this on a traditional computer you would need to run it for each 2 time per bit. so for a 8 bit key for example you would need to run the same operation 256 times 65536 for a 16 bit key and 4,294,967,296 for a 32 bit. so in essence quantum computation just lets you cheat on massively parallel processes but is not a hyper-turring machine or a turring oracle. in fact there are many algorithms that you get no gain from using qubit other than i higher energy bill
    - smegger001 5y ago
      not sure why I am being down voted here perhaps someone needs to do some reading https://en.wikipedia.org/wiki/Quantum_computing#Computability_theory https://en.wikipedia.org/wiki/Quantum_computing#Computabilit... https://www.smbc-comics.com/comic/the-talk-3 https://www.smbc-comics.com/comic/the-talk-3
  - astrange 5y ago
    They are not computably non-deterministic, so they are still Turing machines with a random number generator attached. Qubits aren't magic either and the amount of data they can store is well known, it's just a complex bit instead of a real one.
    - tsimionescu 5y ago
      > they are still Turing machines with a random number generator attached It's important to note that probabilistic Turing machines are different from quantum Turing machines in terms of efficiency, as far as it is known today. But still, that doesn't change the fact that they can (inefficiently) simulate each other.
- IIAOPSW 5y ago
  quantum computers are not just faster classical computers. Quantum algorithms have no classical counterpart. In fact the literal clock speed per quantum computation may be slower but the computation will still get done faster overall.
  - Robotbeat 5y ago
    But there’s no computation a quantum computer can do that a classical computer can’t. In that sense, it’s still a Turing machine. It can do some class of computation faster (in principle).
    - throwaway3699 5y ago
      If we want to reach AGI within the lifetime of the universe, and quantum effects are required for consciousness [within the lifetime etc...], it stands to reason we'd need quantum computers.
      - tsimionescu 5y ago
        Yes, that is true, at least as far as we know today (it's not yet mathematically proven that quantum computers can't be efficiently simulated by probabilistic classical computers, even though we are almost certain of this).
    - hau 5y ago
      Richard Feynman describes such computation, that produces incorrect results on classic computer and correct one on quantum in "Simulating Physics with Computers"[0]. He follows one physical experiment detailing every step from start to finish and how it converges to incorrect result on classical computer. [0] - https://doi.org/10.1007/BF02650179 https://doi.org/10.1007/BF02650179
      - tsimionescu 5y ago
        Thank you for the link! I have also found a free version for anyone else interested: http://physics.whu.edu.cn/dfiles/wenjian/1_00_QIC_Feynman.pdf http://physics.whu.edu.cn/dfiles/wenjian/1_00_QIC_Feynman.pd... However, Feynman does not claim what you say he claims. His whole article is about efficiently simulating QM on a classical computer, and he shows that is not possible given what we understand of quantum probability today, at least (he does this by explicitly asking for a computer which does not grow exponentially in size with the size of the physical system it wants to simulate). In modern CS terms, what he is discussing is whether the complexity classes BPP and BQP are equal or not (as far as we know today, just as he claims, BPP seems to be a smaller subset of BQP, but this is not proven). This is all perfectly in line with my claim, and is in fact explicitly there in Feynman's paper: a classical computer can perfectly simulate a quantum system/computer, but requires exponential time/space to do so (as far as we know).
mikewarot 5y ago
If (a huge if) our memories are stored in qubits, a sufficiently strong magnetic pulse (one much larger than found in an MRI) might be able to erase our brains. This also has interesting (morbid?) implications for how long our memories last after death.

seg_lol 5y ago

Reverse lamp post? We don't routinely take MRIs because of false positives, meaning we might have more questions than answers so we won't ask. Seems like neuroscience is still in the phase of reducing misunderstanding.

mr_toad 5y ago

Microtubules are found in all eukaryotic cells. Even single celled organisms. If microtubules are responsible for cognition, what are brains for, and why aren’t amoeba intelligent?

kortex 5y ago
Have you ever watched an amoeba do its thing? I wouldn't call it cognition, but its behavior is remarkable for something with no neurons. In fact microtubules are the exact structure posited to be responsible for where and how amoebas move their pseudopods. https://pubmed.ncbi.nlm.nih.gov/7983169/ https://pubmed.ncbi.nlm.nih.gov/7983169/
procgen 5y ago
Amoebas are intelligent. All living things are intelligent.