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I think you're missing reading non-hard sciences. In science every analysis that clear states its assumptions and models is valid. You don't have to derive ever

I think you're missing reading non-hard sciences. In science every analysis that clear states its assumptions and models is valid. You don't have to derive everything from axioms and physical laws. You can make assumptions and simplifying models and operate within that, as long as you clearly state your assumptions that may or may not hold -- that's fine. This is common in engineering papers. > Logical bits are not thermodynamic bits They are lower bounded by thermodynamic bits? (in the sense of energy for instance) The thermodynamic bits are exactly that: information (although it seems information in thermodynamic theory is still not perfectly well understood).

mjburgess 4y ago
They arent lower-bounded by thermo bits --- because one can specify algorithms which require no thermodynamic work to implement. Logical bits and thermo bits are related by contingent facts of implementation. One has first to specify an algorithm (defined in terms of a computational model), then it's an open question as to what-and-how it'll be implemented. It's also not at all clear that the physics terms "entropy, information, bits, etc." have anything to do with their computational "equivalents". Only by fairly strained thought experiments do we get alleged connections. Even these thought experiments only provide extremely limited translation of these terms between domains. "Information" in a "logical" sense is a radically different think than in a "thermodynamic sense"... for example, the former has an obvious observer-independent definition, the latter does not. The whole game of trying to bridge these notions without specifying implementation relations (etc.) is largely the new form of that transhumanism-craze: the respectable ideological space of delusional techno-utopian hopes.
- mordechai9000 4y ago
  > one can specify algorithms which require no thermodynamic work to implement Can you give an example? To my limited understanding, performing work without expending energy sounds like perpetual motion.
  - mjburgess 4y ago
    Sure, this is the trap of thinking of computer science as either being about computers (machines) or about science. As mostly a kind of pure discrete mathematics, we need to be careful. Consider an algorithm which says: while(true) state *= +1, state *= -1, state *= +1, ... Now, identify the +1 state as the earth when in one-half of an orbit, and the -1 as the earth in the other half. And therefore the position of the earth as the logical bit ("the state") and its movement as the change to the logical bit. This is "perpetual motion", but the technical name in physics for this is inertial motion, and its common. Motion itself doesn't require work, using that motion for work, requires work. See also https://en.wikipedia.org/wiki/Reversible_computing https://en.wikipedia.org/wiki/Reversible_computing
    - sudosysgen 4y ago
      If you really want to be pedantic, even infinite inertial motion isn't possible, because a true vacuum is impossible, and there is thus necessarily drag somewhere. Also, I've said that before, but we already know that brains operate under an irreversible computation model.
      - User23 4y ago
        > Also, I've said that before, but we already know that brains operate under an irreversible computation model. We don't know that brains operate under any kind of computational model at all. It's often postulated, but it's not proved. Every attempt I've seen at a proof reduces to begging the question. Edit: To be clear I’m not saying a computational model of the brain can’t be a useful tool. Newtonian physics works quite well quite often even though reality isn’t Newtonian.
        sudosysgen 4y ago
        To be clear, I'm not saying that everything the brain does can be modelled by a known computation model. All I'm saying is that the interesting part of what the brain does is computation, in that it takes in data, operates on it, and returns data. It does this in an irreversible manner because you cannot determine the input from the output (nor a significant part of it). If there is any model of how the brain works it will be a computational model. Perhaps a new one, and perhaps a radically different one, but it's still going to find the definition of a computational model.
- sudosysgen 4y ago
  That's pretty much useless, though. We know for a fact that the brain uses irreversible computational processes and that essentially all the input information is erased. So the lower bound is indeed valid. There is indeed a necessary connection between thermodynamic bits and logical bits. Indeed, since we know that we can assume irreversible computation, we know that the computation isn't dominated by those zero-work algorithms. And indeed, if you minimally look at the neuronal model of computation, you can obviously see that computation is going to be irreversible (though reversible calculation is possible in theory). Now, you're right that there is a lot of wiggle-room for implementation, but the lower-bound is indeed robust. So there is clearly value to the argument.
  - mjburgess 4y ago
    Any correspondence between formal properties of the algorithm, namely, the logical model of the system and its physical properties *requires* (1) the algorithm; and (2) the implementation model. Speaking about "computational processes" and "reversibility" at all, absent these, is meaningless. What exactly, of the brain is the "computational process" ? What exactly is "irreversable" ? This is really just pseduo-science, though it may not seem it. We have no idea whatsoever what a logical model of anything to do with animal intelligence is, and hence, absolutely no idea what properties of animals (local to the brain or otherwise) are relevant to them implementing this logical model. To say any process of the brain is "computational" is either to say something useless (namely in the sense in which every process is "presumably, somehow computational, given a logical model") -- or, to say something pseudoscientific. I would agree that animals, in modifying their environments by conceptualising them and developing skillful techniques to regulate themselves in response to them (ie., largely: intelligence), are highly thermodynamically irreversible systems. This isnt a useful observation, given in pseudo-csci terminology, absent a correspondence between this physical facts and the presumed logical model of the computation going on. If the whole of reality is an algorithm, it's one (via energy conservation) which requires zero energy to run. Ie., "logical bit" and "thermal bit" are radically different notions. They are connected contingently when one has an algorithm to-hand, and knows how it will be implemented. There's nothing to be said about the logical bits of animal intelligence, ie., nothing to be said computationally, because we have no idea what they are.

mjburgess 4y ago

They arent lower-bounded by thermo bits --- because one can specify algorithms which require no thermodynamic work to implement. Logical bits and thermo bits are related by contingent facts of implementation. One has first to specify an algorithm (defined in terms of a computational model), then it's an open question as to what-and-how it'll be implemented. It's also not at all clear that the physics terms "entropy, information, bits, etc." have anything to do with their computational "equivalents". Only by fairly strained thought experiments do we get alleged connections. Even these thought experiments only provide extremely limited translation of these terms between domains. "Information" in a "logical" sense is a radically different think than in a "thermodynamic sense"... for example, the former has an obvious observer-independent definition, the latter does not. The whole game of trying to bridge these notions without specifying implementation relations (etc.) is largely the new form of that transhumanism-craze: the respectable ideological space of delusional techno-utopian hopes.

mordechai9000 4y ago
> one can specify algorithms which require no thermodynamic work to implement Can you give an example? To my limited understanding, performing work without expending energy sounds like perpetual motion.
- mjburgess 4y ago
  Sure, this is the trap of thinking of computer science as either being about computers (machines) or about science. As mostly a kind of pure discrete mathematics, we need to be careful. Consider an algorithm which says: while(true) state *= +1, state *= -1, state *= +1, ... Now, identify the +1 state as the earth when in one-half of an orbit, and the -1 as the earth in the other half. And therefore the position of the earth as the logical bit ("the state") and its movement as the change to the logical bit. This is "perpetual motion", but the technical name in physics for this is inertial motion, and its common. Motion itself doesn't require work, using that motion for work, requires work. See also https://en.wikipedia.org/wiki/Reversible_computing https://en.wikipedia.org/wiki/Reversible_computing
  - sudosysgen 4y ago
    If you really want to be pedantic, even infinite inertial motion isn't possible, because a true vacuum is impossible, and there is thus necessarily drag somewhere. Also, I've said that before, but we already know that brains operate under an irreversible computation model.
    - User23 4y ago
      > Also, I've said that before, but we already know that brains operate under an irreversible computation model. We don't know that brains operate under any kind of computational model at all. It's often postulated, but it's not proved. Every attempt I've seen at a proof reduces to begging the question. Edit: To be clear I’m not saying a computational model of the brain can’t be a useful tool. Newtonian physics works quite well quite often even though reality isn’t Newtonian.
      - sudosysgen 4y ago
        To be clear, I'm not saying that everything the brain does can be modelled by a known computation model. All I'm saying is that the interesting part of what the brain does is computation, in that it takes in data, operates on it, and returns data. It does this in an irreversible manner because you cannot determine the input from the output (nor a significant part of it). If there is any model of how the brain works it will be a computational model. Perhaps a new one, and perhaps a radically different one, but it's still going to find the definition of a computational model.
sudosysgen 4y ago
That's pretty much useless, though. We know for a fact that the brain uses irreversible computational processes and that essentially all the input information is erased. So the lower bound is indeed valid. There is indeed a necessary connection between thermodynamic bits and logical bits. Indeed, since we know that we can assume irreversible computation, we know that the computation isn't dominated by those zero-work algorithms. And indeed, if you minimally look at the neuronal model of computation, you can obviously see that computation is going to be irreversible (though reversible calculation is possible in theory). Now, you're right that there is a lot of wiggle-room for implementation, but the lower-bound is indeed robust. So there is clearly value to the argument.
- mjburgess 4y ago
  Any correspondence between formal properties of the algorithm, namely, the logical model of the system and its physical properties *requires* (1) the algorithm; and (2) the implementation model. Speaking about "computational processes" and "reversibility" at all, absent these, is meaningless. What exactly, of the brain is the "computational process" ? What exactly is "irreversable" ? This is really just pseduo-science, though it may not seem it. We have no idea whatsoever what a logical model of anything to do with animal intelligence is, and hence, absolutely no idea what properties of animals (local to the brain or otherwise) are relevant to them implementing this logical model. To say any process of the brain is "computational" is either to say something useless (namely in the sense in which every process is "presumably, somehow computational, given a logical model") -- or, to say something pseudoscientific. I would agree that animals, in modifying their environments by conceptualising them and developing skillful techniques to regulate themselves in response to them (ie., largely: intelligence), are highly thermodynamically irreversible systems. This isnt a useful observation, given in pseudo-csci terminology, absent a correspondence between this physical facts and the presumed logical model of the computation going on. If the whole of reality is an algorithm, it's one (via energy conservation) which requires zero energy to run. Ie., "logical bit" and "thermal bit" are radically different notions. They are connected contingently when one has an algorithm to-hand, and knows how it will be implemented. There's nothing to be said about the logical bits of animal intelligence, ie., nothing to be said computationally, because we have no idea what they are.