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This paper reminds me of one of the "wow" moments I had when first studying neuroscience: a professor passed on the realization that everything in the universe

• srean 5y ago
  But is there infinite regress -- does it have a representation of itself representing itself. I find a more prosaic version of this question quite interesting too. If you can feel a touch/heat anywhere on or in your body its represented in the brain somehow, somewhere. For a moment (i) imagine the brain is sensitive to touch (it isn't because lack of 'pain' receptors) (ii) that the representation of a sensitive part of our body is localized in the brain rather than distributed. What this gives us is a mapping from the entire body (that includes the brain) into itself. Now, if there is a fixed point of this mapping, that fixed point is aware of itself. Is the brain insensitive to touch because its not biologically/physically possible for a localized region of space not to be aware of itself ? EDIT: Downvote ! That was rather unexpected.
  • skohan 5y ago
    Yeah sure it does - probably you can conjure a cartoon in your mind of a brain modeling a brain modeling a brain all the way out to infinity. Maybe you already did when you were coming up with this problem. edit: since the other poster edited their comment, this was only responding to the infinite regression question, not their bizarre point about touch sensitivity
    • XorNot 5y ago
      Similar to the idea of the "infinite image". Take a 640x480 square, and permute every possible combination of pixels. By definition: that space must contain a sizeable, or even complete, portion of all human knowledge that can ever be scrolled or exist in that image space. A lot of noise too, but the complete cure for cancer (if possible), FTL (if possible), immortality: what answers absolutely cannot be represented as several variations of the pixels of a 640x480 image?
  • skohan 5y ago
    To respond to your edit, I don't quite understand what you're getting at. It's quite well understood how the brain represents touch - all the sensory neurons in your skin send information to a brain region which maintains a spacial representation of your body. Your brain isn't sensitive to touch because it's inside your skull, so that touch information wouldn't do a whole lot for you. There's no reason in principal a brain couldn't have pressure sensitive neurons inside of itself or on its surface.
    • srean 5y ago
      No. Even you crack the skull open and poke the brain, it wont feel a thing even when conscious. The skull, the skin will feel, but the brain itself has no pain/tactile receptors. Many surgical procedures on the brain are done with the patient very much awake.
      • skohan 5y ago
        Yeah exactly, why would it?
        • srean 5y ago
          I am just adding to your explanation. The brain is insensitive not because it is "inside your skull" but because of the lack of pain receptors in the brain. Our bone marrow is inside our bones. Trust me, it is not pleasant to touch.
          • skohan 5y ago
            Yeah that's exactly what I was saying. It doesn't need touch receptors because it's inside your skull. It makes sense to evolve pain sensitivity in your bones because if you are doing something which is causing damage inside your bones, you had better have a signal to stop. For most of the evolutionary history of humanity, if your skull was compromised, you would be dead.
            • 5y ago
  • throwanem 5y ago
    I mean, the brain isn't sensitive to touch because it doesn't contain the kind of mechanoreceptors that our nervous system uses to detect that kind of stimulus, which seems like a perfectly sufficient explanation here.
    • srean 5y ago
      Indeed. What I am asking is something different, although I did not word it properly -- Is it even possible for the brain to be sensitive to touch everywhere, or must a teeny-weeny dead-zone exist.
      • skohan 5y ago
        Why would it need to exist? I feel like you're reaching for a philosophical argument here for a question which is already adequately resolved by physics and biology.
        • throwanem 5y ago
          It seems like the question is fundamentally that of whether a given system can perfectly model its own state, but in this context that entails an implicit assumption that the brain's model of body state is perfect, which it is anything but.
          • skohan 5y ago
            I guess I don't really think any system would be able to model it's own state 100% accurately. Basically any model implies a reduction in information. I don't see what this has to do with pain perception in the brain. I am sure you could find an example in the animal kingdom of a creature which has pain receptors in its brain if you look hard enough.
            • srean 5y ago
              Don't get hung up on 'pain perception', my point sits at a higher level of abstraction. It has very little to do with biology, more to do with topology. If 'events at point_a' gets consciously interpreted by participation of cells one of which, lets call it point_b, is singularly dedicated to sensing events at point_a, we have a mapping in a mathematical sense from point a to point b. We know all such point_bs form a strict subset of the body, a part of the central nervous system. If this mapping is continuous in the mathematical sense and a contraction, then a fixed point has to exist (a location that does its own interpretation). But the fixed point seems biologically implausible, that leaves us with the alternative that there has to be dead-zones -- places where events can happen but cannot be interpreted. (Example blind spot in the eye) The way to avoid dead-zone would be to break continuity, or contractive property of the mapping. > I am sure you could find an example … of a creature which has pain receptors in the brain … I think my point would be easier to state for this hypothetical creature. If interpretation of pain is done by a strict subset of its cells and there is a one to one mapping -- at least one location b that interprets pain occurring at location a exclusively (presumably that's how the creature knows the pain is at 'a'), can this creature be free of dead-zones if the mapping is continuous and contractive. Can any creature free of dead-zones exist under those conditions. You claimed 'why not'. I am saying that if the mapping is a continuous contraction then either there has to exist dead zones or there is at least one self interpreting location. To give another example of this phenomenon, if you spread the map of your city somewhere in your city, there has to exist at least one point in the map that sits exactly above the point it is representing -- the fixed point. The way to avoid this would be to have 'tears' in the map, or to have points in your city that are not closer on the map than they are in the city (that would be an unusual map).
• creamytaco 5y ago
  Here is another wow moment that follows from the one you mentioned: The universe you experience is different than my own. We use language and shared culture to consensually hallucinate a "shared" universe but no such thing truly exists for us. We can perceive objects and describe them in similar ways but the fact remains that we can't access the universe that the objects truly exist in (if that even exists) since, for us, they have no independent existence outside of our mental representation. Or shortly, when you die the universe dies with you.
  • srean 5y ago
    That's right. Things that we agree on being named the same we call 'real'. Imagine this, say what everyone perceives as the color red I perceive it as what everyone else perceives as yellow. But since I have been taught the name of the colors by these people, I will end up matching the names of the colors although I am perceiving something very different. This needs to be considered in debates on whether animals have consciousness, do they have an "I". The dominant popular belief is that they aren't. My question is, devoid of a common communication language how would you find out. Only thing we have is their observable external behavior. If that is consistent with the 'consciousness' hypothesis, then that's all we can say. In that case we have about as much evidence of presence of consciousness that a fellow human incapable of communicating with us in language as much as another animal say a dolphin. In both the cases its a hypothesis that explains externally observable behavior. Till we find a way to listen into one's internal monologue this is pretty much all we can do. I like Feynman's example of the 'inside of a brick' no one has seen that with an unaided human eye. Before other forms of sensing the 'inside' came along (X-ray, ultrasound, ...) it was just a hypothesis that fit observable experience. No one would have actually seen the inside of a brick. When you break it open, its no longer the 'inside'. That there is no 'inside' and that a new surface is formed by the be the act of breaking the brick could have been a plausible alternative hypothesis. Existence of an 'inside' is just a simpler hypothesis.
    • BoiledCabbage 5y ago
      > Only thing we have is their observable external behavior. If that is consistent with the 'consciousness' hypothesis, then that's all we can say. In that case we have about as much evidence of presence of consciousness that a fellow human ... It's been mind boggling to me for years that this isn't the default accepted position. That most intelligent life (ie animals) are conscious just like us. Look at what dogs, cats, monkeys do. In what possible way can you say they aren't conscious but another person you can't speak with is? Based on what evidence? The fact we try and reserve consciousness for humans is the most "epi-cycles in support of geocentrism" thing I've ever seen in science. It's silly. It's wholly unscientific, in fact it's anti-science as it actively avoids the most scientific explanation to reach a conclusion that "we're special". Its flawed and a stain on science.
• sampo 5y ago
  In the tv-series Big Bang Theory, there is a moment where Sheldon (a theoretical physicist) and Amy (a neuroscientist) argue, whose discipline is more important and fundamental. Sheldon says that physics studies the fundamental building blocks of the universe. And just like your professor, Amy says something along the lines that neuroscience studies the processes that study the fundamental building blocks of the universe.
  • skohan 5y ago
    I really hate that show, but along those lines I have sometimes wondered if when we are studying theoretical mathematics, are we actually discovering principals about how the universe works, or are we really mapping principals of how the brain processes information without realizing it.
    • esarbe 5y ago
      We're all just the universe wondering about how it can perceive itself.
    • sdwr 5y ago
      Love it, I've had the same thought.
    • foxhop 5y ago
      I love the map analogy, humans have been making those for a long time too. I've always enjoyed maps and mazes and also why I took to mathematics at a young age because it does seem like once you learn basic algorithms you can feel around a problem with numbers and then just get a sense because you know the "map" like the back of your hand. Teaches the next generation, universal way to communicate with other humans at the same level of abstraction, etc.
• bobthechef 5y ago
  I don't see how this is a "wow" moment. It is a straightforward consequence of prior materialist commitments, not a discovery of empirical science. If everything is "matter in motion", then ipso facto all mental activity is matter in motion. The problem is that materialism is completely untenable given the way materialism understands matter (e.g., the problem of qualia, the problem of intentionality, etc). Some materialists realize this, but double down and become eliminativists, which is very sad. Also, from what you have said it does not follow that all "mental content" is to be "located" in the brain. That you have brain correlates is not surprising, if only for the fact that without them you would need to wonder what the heck the brain is doing. But you will not find, in the materialist account, a way in which to account for abstraction in the brain. You cannot account for the concept "square" by appealing to the alone (as opposed to say the image of a particular square).
  • skohan 5y ago
    > But you will not find, in the materialist account, a way in which to account for abstraction in the brain. You cannot account for the concept "square" by appealing to the alone (as opposed to say the image of a particular square). What's wrong with assuming that abstraction is a function of neural activity which is facilitated by specific neural structures and processes?
  • emrah 5y ago
    > I don't see how this is a "wow" moment Questioning, debating and trying to refute someone else's wow moment is a wow moment!