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> Our brains are information-theoretically and complexity-theoretically entirely reasonable. I know this has been the traditional view of most information theo

> Our brains are information-theoretically and complexity-theoretically entirely reasonable. I know this has been the traditional view of most information theorists. But many philosophers (and a few computer scientists) challenge that view. See Fodor's frame problem[1]. The basic idea is this: yes, our brains are complexity-theoretically reasonable after the problem is defined given a set of inputs, outputs, and problem states. However the real issue is how our brains formulate the problem in the first place - how to sort through the combinatorially explosive amount of information in order to narrow down what is relevant to a problem. This objection has never been satisfactorily answered by information theorists in my opinion. The answers given by info theorists always seems to presuppose the existence of a problem formulation before solving it. [1] http://plato.stanford.edu/entries/frame-problem/ http://plato.stanford.edu/entries/frame-problem/

eli_gottlieb 10y ago
Everything in the brain is natively probabilistic. Representations which have low to zero mutual information with the current sensory input are simply not computed-with. You could say that almost all representations will have nonzero mutual information with almost all real-world sensory input, but the sensory input is precision-weighted, so it will take both a sufficiently high degree of mutual information and sufficiently high precision of the activating sense-data to make a given branch of the hierarchy (the whole model is hierarchical, and very large) relevant enough to load it into working memory and use it for prediction.
- myflash13 10y ago
  > Representations which have low to zero mutual information with the current sensory input are simply not computed-with. Who decides that a particular representation in the brain has zero mutual information with current sensory input? This requires a comparison of some sort (i.e. computation).
  - eli_gottlieb 10y ago
    It's a distributed computation that has been mostly precomputed, ie: brain connectivity. And a very popular theory of the brain says it does calculate second-order (precision/entropy) statistics about what it models.
    - myflash13 10y ago
      The combinatorially explosive amount of information that we deal with at every single moment is too large to be dismissed as "precomputed by brain connectivity". If such a large amount of computation could be "precomputed", it has massive implications on our understanding of complexity-theory. Besides it contradicts our subjective feeling of free will, which is why it is not a satisfactory answer for most people.
      - wyager 10y ago
        >combinatorially explosive amount of information that we deal with at every single moment What are you referring to? The sensory input to the brain takes, as a ridiculously high upper bound, perhaps terabits per second. In reality it's probably a few megabits. It's really not much. Vision is, I suspect, by far the highest bandwidth input to our brain, and computer vision has met or exceeded human vision in many tasks.

eli_gottlieb 10y ago

Everything in the brain is natively probabilistic. Representations which have low to zero mutual information with the current sensory input are simply not computed-with. You could say that almost all representations will have nonzero mutual information with almost all real-world sensory input, but the sensory input is precision-weighted, so it will take both a sufficiently high degree of mutual information and sufficiently high precision of the activating sense-data to make a given branch of the hierarchy (the whole model is hierarchical, and very large) relevant enough to load it into working memory and use it for prediction.

myflash13 10y ago
> Representations which have low to zero mutual information with the current sensory input are simply not computed-with. Who decides that a particular representation in the brain has zero mutual information with current sensory input? This requires a comparison of some sort (i.e. computation).
- eli_gottlieb 10y ago
  It's a distributed computation that has been mostly precomputed, ie: brain connectivity. And a very popular theory of the brain says it does calculate second-order (precision/entropy) statistics about what it models.
  - myflash13 10y ago
    The combinatorially explosive amount of information that we deal with at every single moment is too large to be dismissed as "precomputed by brain connectivity". If such a large amount of computation could be "precomputed", it has massive implications on our understanding of complexity-theory. Besides it contradicts our subjective feeling of free will, which is why it is not a satisfactory answer for most people.
    - wyager 10y ago
      >combinatorially explosive amount of information that we deal with at every single moment What are you referring to? The sensory input to the brain takes, as a ridiculously high upper bound, perhaps terabits per second. In reality it's probably a few megabits. It's really not much. Vision is, I suspect, by far the highest bandwidth input to our brain, and computer vision has met or exceeded human vision in many tasks.