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I am skeptical of any paper with this result, because several very plausible events would likely prove by example that computers can respond as a human would. I

I am skeptical of any paper with this result, because several very plausible events would likely prove by example that computers can respond as a human would. It requires accepting certain assumption though. 1: Physicalism is true. Nothing exists that is not part of the physical world. 2: The physical world obeys mathematical laws, and those laws can be learned in time. 2.1: The physical contents of the human body can eventually be learned with arbitrary/sufficient fidelity. 3: Any mathematical rule can be computed by a sufficiently advanced computer. (Edit: or maybe a better assumption: the mathematical laws that underlie the universe are all computable.) 4: Computational power will continue to increase. Subject to these assumptions, we will eventually gain the ability to simulate full physical human beings within computers. Perhaps with some amount of slowdown, but in the end, these simulated humans would be able to converse with entities outside the computer. In all likelihood, computers will pass the Turing test long before this. But if they don't, simulated humans seem like something that is certainly possible or even probable, and therefore the result of this paper is likely incorrect.

krastanov 7y ago
Wait, you forgot one interesting question. This paper claims that a Turing machine can not be a general AI, but it says nothing about other models of computation. The notion that (quantum) Turing machines are the most general/powerful model of computation is only a conjecture, although a very plausible one (usually called the (quantum) extended Church Turing thesis). But even with that in mind, this paper does not seem convincing, including for the reasons you already mentioned. Hopefully it will spark a conversation though.
- asdfasgasdgasdg 7y ago
  I am not an academic neurologist, but I have never read anything convincing that suggests quantum effects are critical to the behavior of human cognition. It may yet be true, but I suspect that classical physics/chemistry is probably sufficiently close to what actually happens to convincingly model human behavior.
  - krastanov 7y ago
    I completely agree with you. I put quantum in parentheses because quantum behavior is important in complexity/computability, and I wanted to be complete. However, yes, there is absolutely no reason to think a human brain possesses that computational capability (and plenty of reasons to suspect it does not).
    - afureta 7y ago
      How does quantum behavior affect computability?
      - H8crilA 7y ago
        It does not. Quantum effects are a smokescreen for clinging onto the idea that "only humans can be human". BQP is quite easily contained in PSPACE, and more generally adding quantum operations does not move one beyond Turing machines (realistically - only something like a halting problem oracle does).
        krastanov 7y ago
        I think you missed the point of my comment. BQP (i.e. "stuff that is efficiently solvable by a quantum computer") is almost certainly bigger than P (i.e. "stuff that is efficiently solvable by classical computers"). There was not even remotely anything in my argument that was claiming "only humans can be human" or "only humans can be intelligent" or anything like that (that would have been a silly claim). And nothing remotely related to claiming quantum effects have anything to do with human brains.
      - krastanov 7y ago
        It affects complexity. Sure, it is fascinating to learn there is a separation between computable and not computable tasks, but there is an important separation among the computable tasks as well. There are "practically computable" tasks (computable with a reasonable complexity) and "computable tasks that are still infeasible in the real universe" (e.g. tasks with exponential complexity). Amusingly, it seems that there are also tasks on the border between between practical and infeasible, that can be practically solved on a quantum computer, but can not be solved in a reasonable time on a classical computer (even one as big as the whole universe). P.S. There was some abuse of naming conventions and nomenclature above. P.P.S. While computability is a well proven concept, claims about complexity (i.e. practical vs infeasible "computable" tasks) are frequently only conjectures (although they have some supporting empirical observations). P.P.P.S. The proper terms to google for as a starting point would be (really, this barely scratches the surface): - complexity class P: computable tasks that can be efficiently solved by a classical computer - complexity class BQP: computable tasks that can be efficiently solved by a quantum computer (and includes tasks that are conjectured to not be efficiently solvable by a classical computer) - complexity class NP-hard: computable tasks that are conjectured to not be solvable by a classical or a quantum computer efficiently (i.e. a medium sized problem would take a computer bigger than the universe to solve)
GTP 7y ago
I also was of the opinion that there was the possibility to reach general AI in the future, but now I will take time to read this paper. I'm not skeptical about it because we know your assumption number 3 to be false: there are mathematical functions that aren't computable. For a proof you can look here [1] or google it. [1] https://www.hse.ru/mirror/pubs/share/198271819 https://www.hse.ru/mirror/pubs/share/198271819
- asdfasgasdgasdg 7y ago
  Thanks. My assumptions are imprecise, because as I mentioned I am no academic. So I appreciate your correction. To make the post stronger, replace assumption 3 with "All of the mathematical rules which underlie physics are computable." IMO, this doesn't materially affect the plausibility of these assumptions.
  - YeGoblynQueenne 7y ago
    >> "All of the mathematical rules which underlie physics are computable." I really have to ask- what are those mathematical rules that underlie physics and how do you know that they are computable?
    - asdfasgasdgasdg 7y ago
      All of chemistry and physics as far as we're aware are described by mathematical rules that can be computed. Things like the strong and weak forces, gravity, etc. all have mathematical descriptions. There may be other, non-computable aspects to physics, but I am not aware of them if so.
      - deleted 7y ago
        [deleted]
      - YeGoblynQueenne 7y ago
        >> There may be other, non-computable aspects to physics, but I am not aware of them if so. In that case, what do you base your assumption (3) on?
djakjxnanjak 7y ago
How many particles make up a human, and how many transistors does it take to simulate the behavior and interactions of all those particles? How much energy does it take to power that many transistors? How does that compare to the Sun’s output? There are a few of the questions we need to answer before confidently predicting that we will ever be able to make a physics-based human simulator.
- asdfasgasdgasdg 7y ago
  Yep. This is not a strong proof that humans are simulable, and I don't intend it to be. And I don't meant to suggest that simulating a human particle for particle will ever be an efficient way to model human behavior. I suspect that even medium fidelity neural simulations will someday be sufficient. Instead, the list is meant to inspire an engagement at the level of: "which of these assumptions do I disbelieve?" For it to be the case that computers cannot mimic human-level intelligence, at least one of these items have to be false. And I consider the last one to be the weakest to attack, because all you're really saying there is that it will never be practical, not that it will never be possible. I think disbelieving any of the other assumptions makes a stronger statement, but I also think they are the harder ones to disbelieve.
  - djakjxnanjak 7y ago
    I’ve thought along these lines myself, and I do wonder if we’re going to approach general AI by finding ways to “compress” a simulation of a human brain, or just by coming up with new neural net architectures. The second approach is the one everybody’s working on, and to me it seems more practical.
rfugger 7y ago
I think your premises are fair, but assumption #3 ("Any mathematical rule can be computed by a sufficiently advanced computer") is effectively ruled out by Gödel's incompleteness theorem[1] and/or the Church-Turing thesis[2]. The problem then becomes finding an approach to general AI that avoids hitting incompleteness/undecidability[3] issues. My feeling is that this would be difficult. One way to try to avoid these issues is to avoid notions of self-reference, since self-reference spawns a lot of undecidable stuff (eg, "this statement is false" is neither true nor false). It seems to me, though, that the notions of the self and self-awareness are central to human consciousness, and so unavoidable when developing a complete simulation of human consciousness. The self is probably not computable. Obviously there could be approaches that avoid these pitfalls, but every year that goes by without much progress towards general AI makes me feel more confident in this intuition. I do think there will be lots of useful progress in specialized AIs, but I see this as analogous to developing algorithms to decide the halting problem for special classes of algorithms. General AI is a whole different beast. But if general AI is physically impossible, how does the human brain "compute" general intelligence at all? It could be that your assumption #1 ("Physicalism is true. Nothing exists that is not part of the physical world.") is not correct. Maybe reality has "layers" and our world is some kind of simulation in another layer. Or maybe there is only one consciousness like many spiritual people and Boltzmann[4] suggest. Or maybe the human experience could be a process of trying to solve an undecidable problem and failing... 1. https://en.wikipedia.org/wiki/G%C3%B6del%27s_incompleteness_theorems https://en.wikipedia.org/wiki/G%C3%B6del%27s_incompleteness_... 2. https://en.wikipedia.org/wiki/Church%E2%80%93Turing_thesis https://en.wikipedia.org/wiki/Church%E2%80%93Turing_thesis 3. https://en.wikipedia.org/wiki/Undecidable_problem https://en.wikipedia.org/wiki/Undecidable_problem 4. https://en.wikipedia.org/wiki/Boltzmann_brain https://en.wikipedia.org/wiki/Boltzmann_brain
- asdfasgasdgasdg 7y ago
  In another reply, I modified point three to be the assumption that all of the physical laws of the universe are defined by computable maths. I believe this is the case to the best of our knowledge, but please let me know if I'm wrong.
  - 7y ago

krastanov 7y ago

Wait, you forgot one interesting question. This paper claims that a Turing machine can not be a general AI, but it says nothing about other models of computation. The notion that (quantum) Turing machines are the most general/powerful model of computation is only a conjecture, although a very plausible one (usually called the (quantum) extended Church Turing thesis). But even with that in mind, this paper does not seem convincing, including for the reasons you already mentioned. Hopefully it will spark a conversation though.

asdfasgasdgasdg 7y ago
I am not an academic neurologist, but I have never read anything convincing that suggests quantum effects are critical to the behavior of human cognition. It may yet be true, but I suspect that classical physics/chemistry is probably sufficiently close to what actually happens to convincingly model human behavior.
- krastanov 7y ago
  I completely agree with you. I put quantum in parentheses because quantum behavior is important in complexity/computability, and I wanted to be complete. However, yes, there is absolutely no reason to think a human brain possesses that computational capability (and plenty of reasons to suspect it does not).
  - afureta 7y ago
    How does quantum behavior affect computability?
    - H8crilA 7y ago
      It does not. Quantum effects are a smokescreen for clinging onto the idea that "only humans can be human". BQP is quite easily contained in PSPACE, and more generally adding quantum operations does not move one beyond Turing machines (realistically - only something like a halting problem oracle does).
      - krastanov 7y ago
        I think you missed the point of my comment. BQP (i.e. "stuff that is efficiently solvable by a quantum computer") is almost certainly bigger than P (i.e. "stuff that is efficiently solvable by classical computers"). There was not even remotely anything in my argument that was claiming "only humans can be human" or "only humans can be intelligent" or anything like that (that would have been a silly claim). And nothing remotely related to claiming quantum effects have anything to do with human brains.
    - krastanov 7y ago
      It affects complexity. Sure, it is fascinating to learn there is a separation between computable and not computable tasks, but there is an important separation among the computable tasks as well. There are "practically computable" tasks (computable with a reasonable complexity) and "computable tasks that are still infeasible in the real universe" (e.g. tasks with exponential complexity). Amusingly, it seems that there are also tasks on the border between between practical and infeasible, that can be practically solved on a quantum computer, but can not be solved in a reasonable time on a classical computer (even one as big as the whole universe). P.S. There was some abuse of naming conventions and nomenclature above. P.P.S. While computability is a well proven concept, claims about complexity (i.e. practical vs infeasible "computable" tasks) are frequently only conjectures (although they have some supporting empirical observations). P.P.P.S. The proper terms to google for as a starting point would be (really, this barely scratches the surface): - complexity class P: computable tasks that can be efficiently solved by a classical computer - complexity class BQP: computable tasks that can be efficiently solved by a quantum computer (and includes tasks that are conjectured to not be efficiently solvable by a classical computer) - complexity class NP-hard: computable tasks that are conjectured to not be solvable by a classical or a quantum computer efficiently (i.e. a medium sized problem would take a computer bigger than the universe to solve)

GTP 7y ago

I also was of the opinion that there was the possibility to reach general AI in the future, but now I will take time to read this paper. I'm not skeptical about it because we know your assumption number 3 to be false: there are mathematical functions that aren't computable. For a proof you can look here [1] or google it. [1] https://www.hse.ru/mirror/pubs/share/198271819 https://www.hse.ru/mirror/pubs/share/198271819

asdfasgasdgasdg 7y ago
Thanks. My assumptions are imprecise, because as I mentioned I am no academic. So I appreciate your correction. To make the post stronger, replace assumption 3 with "All of the mathematical rules which underlie physics are computable." IMO, this doesn't materially affect the plausibility of these assumptions.
- YeGoblynQueenne 7y ago
  >> "All of the mathematical rules which underlie physics are computable." I really have to ask- what are those mathematical rules that underlie physics and how do you know that they are computable?
  - asdfasgasdgasdg 7y ago
    All of chemistry and physics as far as we're aware are described by mathematical rules that can be computed. Things like the strong and weak forces, gravity, etc. all have mathematical descriptions. There may be other, non-computable aspects to physics, but I am not aware of them if so.
    - deleted 7y ago
      [deleted]
    - YeGoblynQueenne 7y ago
      >> There may be other, non-computable aspects to physics, but I am not aware of them if so. In that case, what do you base your assumption (3) on?

djakjxnanjak 7y ago

How many particles make up a human, and how many transistors does it take to simulate the behavior and interactions of all those particles? How much energy does it take to power that many transistors? How does that compare to the Sun’s output? There are a few of the questions we need to answer before confidently predicting that we will ever be able to make a physics-based human simulator.

asdfasgasdgasdg 7y ago
Yep. This is not a strong proof that humans are simulable, and I don't intend it to be. And I don't meant to suggest that simulating a human particle for particle will ever be an efficient way to model human behavior. I suspect that even medium fidelity neural simulations will someday be sufficient. Instead, the list is meant to inspire an engagement at the level of: "which of these assumptions do I disbelieve?" For it to be the case that computers cannot mimic human-level intelligence, at least one of these items have to be false. And I consider the last one to be the weakest to attack, because all you're really saying there is that it will never be practical, not that it will never be possible. I think disbelieving any of the other assumptions makes a stronger statement, but I also think they are the harder ones to disbelieve.
- djakjxnanjak 7y ago
  I’ve thought along these lines myself, and I do wonder if we’re going to approach general AI by finding ways to “compress” a simulation of a human brain, or just by coming up with new neural net architectures. The second approach is the one everybody’s working on, and to me it seems more practical.

rfugger 7y ago

I think your premises are fair, but assumption #3 ("Any mathematical rule can be computed by a sufficiently advanced computer") is effectively ruled out by Gödel's incompleteness theorem[1] and/or the Church-Turing thesis[2]. The problem then becomes finding an approach to general AI that avoids hitting incompleteness/undecidability[3] issues. My feeling is that this would be difficult. One way to try to avoid these issues is to avoid notions of self-reference, since self-reference spawns a lot of undecidable stuff (eg, "this statement is false" is neither true nor false). It seems to me, though, that the notions of the self and self-awareness are central to human consciousness, and so unavoidable when developing a complete simulation of human consciousness. The self is probably not computable. Obviously there could be approaches that avoid these pitfalls, but every year that goes by without much progress towards general AI makes me feel more confident in this intuition. I do think there will be lots of useful progress in specialized AIs, but I see this as analogous to developing algorithms to decide the halting problem for special classes of algorithms. General AI is a whole different beast. But if general AI is physically impossible, how does the human brain "compute" general intelligence at all? It could be that your assumption #1 ("Physicalism is true. Nothing exists that is not part of the physical world.") is not correct. Maybe reality has "layers" and our world is some kind of simulation in another layer. Or maybe there is only one consciousness like many spiritual people and Boltzmann[4] suggest. Or maybe the human experience could be a process of trying to solve an undecidable problem and failing... 1. https://en.wikipedia.org/wiki/G%C3%B6del%27s_incompleteness_theorems https://en.wikipedia.org/wiki/G%C3%B6del%27s_incompleteness_... 2. https://en.wikipedia.org/wiki/Church%E2%80%93Turing_thesis https://en.wikipedia.org/wiki/Church%E2%80%93Turing_thesis 3. https://en.wikipedia.org/wiki/Undecidable_problem https://en.wikipedia.org/wiki/Undecidable_problem 4. https://en.wikipedia.org/wiki/Boltzmann_brain https://en.wikipedia.org/wiki/Boltzmann_brain

asdfasgasdgasdg 7y ago
In another reply, I modified point three to be the assumption that all of the physical laws of the universe are defined by computable maths. I believe this is the case to the best of our knowledge, but please let me know if I'm wrong.
- 7y ago