On Oct 18, 9:57 pm, Stathis Papaioannou <stath...@gmail.com> wrote: > On Tue, Oct 18, 2011 at 1:01 PM, Craig Weinberg <whatsons...@gmail.com> wrote: > >> The speech centres must, through a relay of neurons, receive > >> information from the visual centres if the subject is to make any > >> statement about what he sees. > > > What makes you think that's the case? That's a blatant fallacy, isn't > > it? "The windshield wipers must, through a relay of mechanical parts, > > receive music from the from the radio station" > > > Visual centers don't talk, and speech centers don't see. People see > > and talk. > > When you speak about what you see the information carried in the light > that comes into your pupils must somehow get to the motor neurons > controlling your vocal cords. How do you think this happens?
There is no 'information' carried in the light. There is only the sense that the visual cortex makes of the sense that the retina makes of the sense that the optical relations of the environment make to the person who is using the the visual cortex and retina to perceive the environment. At no point would anything that enters your pupils wind up coming out of your vocal chords through your motor neurons. I am flabbergasted that you can take this view seriously in all honesty. Aren't you saying that you think nuggets of 'information' from outside of your eyeballs are squirting into your brain and out of your throat? How I think it happens that we can speak about what I see is that the cells of my retina experience a photosynthetic sense of their environment. The cells of my visual cortex experience a neurological sense of the retina's sense, which it arrives at by sharing it's own sense (image) with the sense of other participating parts of the brain - some conscious, like attention and focus, some subconscious like pattern recognition, and some unconscious like color and motion. The visual cortex is only part of what we experience of sight, the rest is influenced by our expectations and memories, which are the senses of other regions of the brain. The overall sensemaking of the brain that we have conscious access to, including limbic feelings, prefrontal cognitions, etc, are all involved in building a consensus - a mutual, bi-directional process between the different channels of sensemaking and the executive intentions. That understanding is all that is communicated through the motor control of the vocal cords. There is no transduced visual 'information' present in our larynx or in the spasmodic manipulations thereof. > > > > > > > > > > >> If the visual centres are artificial, > >> but producing the same neural outputs to the rest of the brain, > > > They probably won't though. They can't because they don't feel the > > appropriate qualia to repspond to events in the same way over time. It > > depends how close they are to natural neurons, maybe even the neurons > > which are genetically specific to that individual. > > >> then > >> the rest of the brain will respond as if vision is normal: > > > If there is some part of the natural visual centers there, they may > > very well be able to use the artificial ones as a substitute - like a > > cane, but you can't use a cane as a substitute for your whole arm. > > >> the subject > >> will say everything looks normal, he will grasp things normally with > >> his hands, he will paint or write poetry about what he sees normally. > >> His motor cortex cannot be aware that the visual cortex has changed, > >> since the only awareness of the outside world the motor cortex can > >> have must come through the surrounding tissue. > > > I understand how you are thinking about it, but I think that would > > make sense if there were a such thing as functional equivalence of > > qualia, but qualia has no function. There is no way to know if you can > > make something that feels just like a neuron unless it is in fact a > > natural neuron. > > >> > Since we know absolutely that we have experiences which cannot be > >> > observed directly in the tissue of the brain, there is no sense in > >> > imagining that replicating what we observe in the brain will not be > >> > missing crucial capacities which we can't anticipate. Even replacing > >> > simpler organs with actual human organs have a risk of rejection. Why > >> > would the brain, which is presumably infinitely more sensitive than a > >> > kidney, have no problem with a completely theoretical and unrealizably > >> > futuristic artificial device? > > >> We assume that the artificial device reproduces the pattern of neural > >> firing and nothing else. Do you think that is *impossible*? Why? > > > Sure, it might be impossible. Because the pattern is context > > dependent. If you have a bunch of separate heart cells, they will all > > beat regularly but not synchronized. So you make an artificial heart > > cell that beats regularly at the same interval as any of the other > > heart cells. When you put all of the separate heart cells in a dish > > together, they all will synchronize - except the artificial ones. If > > you were to put enough artificial heart cells in a living heart, you > > would cause an arrhythmia and kill the person who is using that heart > > to live. > > Cadrdiac myocytes in culture can synchronise their beating through > direct contact. Artificial myocytes, if they were to replicate this > behaviour, would have to be sensitive to the action potential of the > natural myocytes. > In general, any observable behaviour of the > biological system that you want to replicate can be replicated by some > technology. Observable by what? If a cat replicated their owner, you would probably have a very large and interesting smelling can opener. >Qualia are not observable Qualia is the only thing that can ever be observed directly. It is only through inference and reason that we can imagine a world outside of that. > and it is an open question > whether they can be replicated, so we assume that they can't and > consider the consequences. The consequences are that a person's qualia > might change but, because the inputs to the motor neurons controlling > speech are the same, he would declare that nothing has changed. This is your fantasy, not mine. Since the 'inputs' to the motor neurons have little to do with the mechanics which deliver the qualia experiences and more to do with the sense that the person makes out of the qualia, the speech is not controlled by anything but how the person feels about their experience. You could control the speech electronically - and make the larynx say what you want it to say, but you can do that to a cadaver too - it proves nothing. > > > Neurons are orders of magnitude more interconnected than that. The > > idea that there is a fixed 'pattern of neural firing' which can be > > derived from a single neuron in isolation that can be extrapolated out > > to the brain as a whole is just factually incorrect. It's not some > > exotic wackiness that I dreamed up, it's actually not at all the way > > that the brain, or any living organism works. Neurons aren't just > > miniature brains, and brains aren't just a pile of neurons. It's like > > assuming that if you make a mannequin that acts like a nomadic hunter > > gatherer, you should have no trouble repopulating New York, London, > > and Hong Kong with a large group of them. > > I keep repeating that there is no "pattern of neural firing" to > replicate. Whether a biological neuron fires or not depends on its > present state and its inputs. A neuron that would fire if the > temperature is 37 degrees and the extracellular potassium > concentration is 5 mM might not fire if the temperature is 39 degrees > and the potassium concentration 6 mM. It's true that you can control the firing of a neuron from the outside - as you say, changing temperature, electrolyte or neurotransmitter concentrations, etc. That's medicine. But that isn't what is going on right now as you and I type on our keyboards. We are driving the behavior. Our intention alone is changing the instrument of the brain, firing thousands of neurons at a time over many different regions - not chain reactions, but parallel chords of simultaneous change instantiated in a single high level firing pattern. You can see that clearly in the MRI animations. You keep repeating something that is factually incorrect and a misrepresentation of neurology. >The model of the neuron has to > incorporate knowledge about how the neuron is affected by these > variables, and this knowledge is obtained through research. But the > model cannot predict what the temperature or the potassium > concentration is going to be at a particular time, since neither can > the biological neuron. Your mistaking the unconscious change in variables associated with conscious activity for the cause of conscious activity. All we know is that the two phenomenologies are correlates. There is nothing to support the idea that conscious activity does not also cause these changes - quite the opposite. We can tell a person to think about something in particular and have them light up a part of their brain on an MRI. We can do that verbally and semantically - not by introducing a chemical change into the brain directly. 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