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"DNA can encode everything the brain does with N bits of information" It doesn't directly encode the structure of the brain. Development is required. "Involve

by api 16y ago

"DNA can encode everything the brain does with N bits of information" It doesn't directly encode the structure of the brain. Development is required. "Involved" is a serious weasel word when it comes to the brain, especially when AI is under discussion; everything in your skull is "involved" in cognition, but that doesn't mean it's doing anything particularly important, and it definitely does not mean that every detail of the dynamics is an absolute necessity to obtain Cognition. But I think we might be arguing different things... We are arguing different things. My point is that you can't write a little equation for a neuron (which is an entire living cell!) and wave your hands and say "done!" Kurzweil is way way way too hand-wavey for me.

bsaunder 16y ago
It doesn't directly encode the structure of the brain. Development is required. Your Java program doesn't directly execute on the CPU, compilation and interpretation are required.
- api 16y ago
  Totally different thing. The java program encodes each decision and computation that it performs directly.
  - bsaunder 16y ago
    No a Java program requires an environment to run, so does a brain . It's just that a brain alters it's behavior and structure as a result of processing inputs (development). We don't (normally) write Java programs to change their behavior as they process information from their environment during execution.
    - api 16y ago
      You're confusing literal translation with development. Here's a very loose conceptual analogy: Translation: translating Lord of the Rings into Chinese. Development: hearing a short plot synopsis of Lord of the Rings and writing your own fantasy novel based on the same theme. Development really does do something analogous to that. It takes a collection of proteins and rules and, through embodiment within the laws of physics, constructs the phenotype. The phenotype contains vastly more information than the genotype, and two identical genotypes will not produce absolutely identical phenotypes. There is something fundamental about development that we do not understand. This is widely acknowledged in the developmental biology, evo-devo, and evolutionary computation fields. A closer analogy than the loose one above might be some of the behaviors we see with fractals and cellular automata, though development is less deterministic than that. Evolution and development are somehow related. We don't quite get that either. But both processes add vast amounts of information and both involve adaptation.
      - DougBTX 16y ago
        Hand waving: the adult brain is the output of running a program stored in DNA for twenty years on a runtime (the physical universe) we can barley understand. To produce a brain from the data stored in DNA, we would need to simulate the runtime environment. To do that without simulating the whole universe, we would need to work out which subset of the universe to simulate. We are far away from knowing what shape that subset takes, let alone what the minimal number of bytes required to simulate it is.
ewjordan 16y ago
My point is that you can't write a little equation for a neuron (which is an entire living cell!) and wave your hands and say "done!" Kurzweil is way way way too hand-wavey for me. Yes, we're in full agreement on this, especially the part about Kurzweil - I don't think he advances the science of this at all, and his poppy PR approach rubs me the wrong way, for sure, as do many of his specific ideas. In particular, I think it's a terrible idea to hinge our hopes for AI on the idea that we'll be able to carry out a perfect enough simulation of a full brain to call it "done". Not only does it seem to be a pipe dream at present, depending on a whole bunch of technological advances that may not come for a long time, it would be almost completely inextensible and teach us very little - once we had such a simulation running, it's unlikely that we'd understand enough about how to modify it to improve upon it. I don't quarrel with the idea that DNA encodes the brain extremely indirectly at all, including a substantial development process that depends on a lot of things other than the pure genetic code, and I also agree that the dynamics of a brain are very dependent on the details of all sorts of cells, not just an oversimplified logical representation of them. Where I think we start to diverge is that I have issues with the idea that the particulars of any of those processes can somehow "piggy-back" any non-trivial amount of functionality into the system that's not coming from the genetic code. Here's the clearest way, I think, to state my information-content claim: if we were to randomly change the details of the way neurons function in detail (still leaving them with the same highest-level capabilities), and randomly change the way brain development happens, and randomly change all steps of entire process that leads from DNA->brain (again, subject to the restriction that the whole thing still works), and even - I daresay - randomly change the laws of physics, then... ...if all of these changes still permitted us to write down any string of DNA (or whatever our new version of DNA was) that ultimately resulted in the growth of an intelligent human brain, the amount of DNA required would, on average, be pretty darn close to the amount that we see used today. And that has implications for other implementations of the same logic, namely that if we could find some way to optimize towards whatever solution evolution has found, we could probably end up with a shorter code for it than evolution has because we can allow all parts of the DNA->brain process to optimize for compression whereas the real physical process is largely frozen against change. That's the sense in which I think Kurzweil has a reasonable estimate, nothing more, nothing less; where he takes it from there is another story altogether. :)

by api 16y ago

bsaunder 16y ago

It doesn't directly encode the structure of the brain. Development is required. Your Java program doesn't directly execute on the CPU, compilation and interpretation are required.

api 16y ago
Totally different thing. The java program encodes each decision and computation that it performs directly.
- bsaunder 16y ago
  No a Java program requires an environment to run, so does a brain . It's just that a brain alters it's behavior and structure as a result of processing inputs (development). We don't (normally) write Java programs to change their behavior as they process information from their environment during execution.
  - api 16y ago
    You're confusing literal translation with development. Here's a very loose conceptual analogy: Translation: translating Lord of the Rings into Chinese. Development: hearing a short plot synopsis of Lord of the Rings and writing your own fantasy novel based on the same theme. Development really does do something analogous to that. It takes a collection of proteins and rules and, through embodiment within the laws of physics, constructs the phenotype. The phenotype contains vastly more information than the genotype, and two identical genotypes will not produce absolutely identical phenotypes. There is something fundamental about development that we do not understand. This is widely acknowledged in the developmental biology, evo-devo, and evolutionary computation fields. A closer analogy than the loose one above might be some of the behaviors we see with fractals and cellular automata, though development is less deterministic than that. Evolution and development are somehow related. We don't quite get that either. But both processes add vast amounts of information and both involve adaptation.
    - DougBTX 16y ago
      Hand waving: the adult brain is the output of running a program stored in DNA for twenty years on a runtime (the physical universe) we can barley understand. To produce a brain from the data stored in DNA, we would need to simulate the runtime environment. To do that without simulating the whole universe, we would need to work out which subset of the universe to simulate. We are far away from knowing what shape that subset takes, let alone what the minimal number of bytes required to simulate it is.

ewjordan 16y ago

My point is that you can't write a little equation for a neuron (which is an entire living cell!) and wave your hands and say "done!" Kurzweil is way way way too hand-wavey for me. Yes, we're in full agreement on this, especially the part about Kurzweil - I don't think he advances the science of this at all, and his poppy PR approach rubs me the wrong way, for sure, as do many of his specific ideas. In particular, I think it's a terrible idea to hinge our hopes for AI on the idea that we'll be able to carry out a perfect enough simulation of a full brain to call it "done". Not only does it seem to be a pipe dream at present, depending on a whole bunch of technological advances that may not come for a long time, it would be almost completely inextensible and teach us very little - once we had such a simulation running, it's unlikely that we'd understand enough about how to modify it to improve upon it. I don't quarrel with the idea that DNA encodes the brain extremely indirectly at all, including a substantial development process that depends on a lot of things other than the pure genetic code, and I also agree that the dynamics of a brain are very dependent on the details of all sorts of cells, not just an oversimplified logical representation of them. Where I think we start to diverge is that I have issues with the idea that the particulars of any of those processes can somehow "piggy-back" any non-trivial amount of functionality into the system that's not coming from the genetic code. Here's the clearest way, I think, to state my information-content claim: if we were to randomly change the details of the way neurons function in detail (still leaving them with the same highest-level capabilities), and randomly change the way brain development happens, and randomly change all steps of entire process that leads from DNA->brain (again, subject to the restriction that the whole thing still works), and even - I daresay - randomly change the laws of physics, then... ...if all of these changes still permitted us to write down any string of DNA (or whatever our new version of DNA was) that ultimately resulted in the growth of an intelligent human brain, the amount of DNA required would, on average, be pretty darn close to the amount that we see used today. And that has implications for other implementations of the same logic, namely that if we could find some way to optimize towards whatever solution evolution has found, we could probably end up with a shorter code for it than evolution has because we can allow all parts of the DNA->brain process to optimize for compression whereas the real physical process is largely frozen against change. That's the sense in which I think Kurzweil has a reasonable estimate, nothing more, nothing less; where he takes it from there is another story altogether. :)