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Thread: Technological Singularity

  1. #46
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    Quote Originally Posted by 3 Body No Problem View Post
    No, it's the same, just more politely expressed.

    The question is: do we to go down to the level of QM to explain biological phenomena, i.e. how the proteins work in cells, or can all of this be explained classically?

    The people who are argue for quantum biology all say: in the future we will find biological effects that can only be explained with reference to quantum phenomena. Their detractors say: there is currently no example where we know that it cannot be explained classically, please quantum biology guys & girls show us one.

    A strong form of detractors says: biological entities (like macro molecules) are too large to exhibit quantum effects due to decoherence..

    I'm not a physicist, please correct me if I'm wrong, but I think the strong detractor's claim touches on an interesting open problem on physics (which is also key to the question whether we can build real quantum computers): can large systems exhibit quantum effects, or not. Nothing in quantum mechanics as we understand it today says there cannot be macroscopic quantum effects, but there seem to be serious obstacles to scaling quantum effects to macroscopic systems. They may just be engineering problems that will eventually be overcome, but it is also possible that there is a fundamental scale limitation to quantum effects which we don't understand.



    Biology is based on chemistry, and chemisty is based on quantum mechanics. However, for large systems, quantum mechanics (as far as we know) collapses to classical mechanics, and consequently we work with classical physics in biology. The claim of quantum biologists is that there are biological phenomena that cannot be explained classically.

    Ahhhhh...now a couple of things from the debate make more sense.

    I don't know, I think I'm with the "Yes" team on this. There are plenty of things that we just can't explain yet with reference to classical explanations (biomechanical ones), viz., for example, how spindle fibers/microtubules move down a cell during mitosis. In fact, there are plenty of microbiological processes that work and we just can't figure out how the cells parts know to move this way or that way--what is attracting them?? This doesn't mean that we will never discover a way to explain them with reference to classical physics, but I wouldn't be shocked if somebody comes up with a wacky and awesome quantum explanation. There does seem to be a gaping whole at the center of microbiology just waiting to be filled by somebody.

    Why not think big? (Or small...whatever...)

  2. #47
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    Quote Originally Posted by Mr. Tea View Post
    But macromolecules are made up of micromolecules, aren't they? And micromolecules are made up of atoms. I mean, genetic nucleotides are pretty small, and molecules bigger than that (Buckyballs, for example) have been shown to exhibit explicitly quantum-mechanical behavior, viz. diffracting when you pass a beam of them through a narrow slit.

    Then in the brain you've got nitrous oxide acting as a neurotransmitter, and that's only got three atoms - not to mention the individual potassium/sodium ions involved in the transmission of nerve impluses. Decoherence time is, AFAIR, inversely proportional to the size* of the system under consideration, so it's much longer for a single atom or a monocyclic molecule than for, say, a whole protein or something.


    *not sure if this means mass or length scale, but doesn't substantially change the argument
    Oh yes there are some amazingly simple and elegant neurotransmitters, including all kinds of ions. Ca 2+ is a fav of mine.

    Are you saying here that the quantum tendencies of a system cohere longer in a more complex system? Or can't this be expressed this way?

  3. #48
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    Quote Originally Posted by nomadthethird View Post
    Are you saying here that the quantum tendencies of a system cohere longer in a more complex system? Or can't this be expressed this way?
    I don't think complexity is the main thing, it's more to do with size. Bigger systems decohere faster, meaning there's less time for quantum interference between different states, not more. Though it seems reasonable to assume bigger systems are generally more complex than smaller ones.
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  4. #49
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    Quote Originally Posted by Mr. Tea View Post
    Thing is, exponential increase just keeps getting gradually steeper and steeper, there's no sudden cut-off moment where everything goes "WHOOSH!" all in one go. I think the idea of the Singularity is that some breakthrough is made which enables not merely a quantitative change in the pace of technological innovation, which after all is happening all the time (Moore's law) , but a qualitative shift so that a graph of processor power or whatever vs. time effectively looks like a vertical wall.

    One possible catalyst people have mentioned already could be computers that are better at designing things than we are - genetic algorithms and the like. Another could be quantum computers, which (once some fairly substantial practical difficulties are solved) offer effectively limitless computing power. I think some theorists think they may even be able to solve problems that are even in principle insoluble to classical Turing machines (eg. common-or-garden computers as they exist today). Then there's work people have been doing with pieces of DNA, using base pairs as digits to perform immensely complex calculations...some people think DNA/RNA can unzip and re-zip much more quickly than it 'should' be able to according to semi-classical molecular dynamics, which means the nucleotides may be existing in quantum superposition before actually binding to the phosphate backbone to complete the reaction.

    I dunno if it counts as a fully-fledged subdiscipline yet, but people are already writing papers on 'quantum biology'. And some of them have a bit more of a basis in experimental reality than Penrose's magic tubules, too.
    its actually pretty cool listening to tea talk about something he knows about.

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  6. #50
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    Nomadologist had a favourite neurotransmitter! I would say we'd have been perfect together, but I fear craner would track me down and murder me in a jealous rage.
    Last edited by Mr. Tea; 07-05-2018 at 08:19 PM.
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