On Wed, Oct 12, 2011 at 4:17 AM, Craig Weinberg <whatsons...@gmail.com> wrote:
>>The model of a neuron does not include the inputs. A >> larger model of a network of neurons includes inputs and outputs from >> all the neurons in the network but does not include external inputs. > > Without any external inputs, and without any recognition of internal > spontaneous activity, what is it that this closed circuit of neurons > would be inputting and outputting that would be worth modeling? The external inputs themselves are not modelled, they are provided by the environment. >> I really can't understand your emotional objection to the idea that >> consciousness may be epiphenomenal and supervenient on mechanistic >> processes. It doesn't worry me or affect my behaviour; why should it? > > If consciousness were epiphenomenal and supervenient on mechanistic > processes, you would not have a choice whether or not to worry. You > would have no opinion, and there could be no such thing as an opinion. > My objection is that it's a nonsensical position. It's not nonsensical: I can understand it and it is not self-contradictory. >> Physical events in my brain lead me to choose the words and on top of >> this process is the subjectivity of choice. > > What do you mean by 'me'? Your whole position is that it is impossible > for your brain to lead anything except itself to do anything except > what it has to do by physical law. Where does a 'subjectivity of > choice' come in? Where is it located? What is it made out of? How does > it relate to the brain? "I" am the result of the activity of the ensemble of neurons in my brain. Subjectivity results because that is what it feels like when information is processed the way it is in the brain. "Choice" is when I have two alternatives and I feel I can freely choose between them, which is consistent with the decision being ultimately either random or determined. >> What is this "electromagnetism" you have mentioned several times? The >> action potential generates an electromagnetic field and some theories >> of consciousness hold this to be important, is that what you mean? > > An action potential is just a word for the electromagnetic change > within the cell membrane which passes on to other cells. The action potential is the spike in potential difference between the two sides of a cell membrane that propagates down the membrane, generating an electromagnetic field. >> It's not mainstream neuroscience but in any case, electromagnetic >> fields are well-understood physical phenomena, probably more easily >> modelled mathematically than biochemistry is. > > Do you agree that neurological activity corresponds to human > perceptions? Yes. > Do you agree that neurological activity is chemical and electrical > activity? Yes. > Do you agree that chemical and electrical activity are both forms of > electromagnetic activity? Chemistry is ultimately the result of the electromagnetic force. > If so, then it is not possible that human perceptions are not in some > way electromagnetic. I don't know in what sense it is accurate to say that. Consciousness is somehow different to the brain activity, though some hard core reductionists insist that it is identical to it and there is nothing further to explain. >> There are two types of ion channels, voltage-dependent and >> ligand-dependent. The votage-activated ones open when the potential >> difference across the membrane is at a certain level: >> the electric >> field generated as a result of this potential difference changes the >> shape of the ion channel, which is a transmembrane protein, and this >> opens the channel to allow the specific ion to pass through. > > What changes the potential difference in the first place? What relates > any of that to our subjective experience? > >> Ligand-activated ion channels open when a specific neurotransmitter >> binds. The transmembrane potential changes as a result of ion fluxes: >> potassium is more concentrated inside the cell so when potassium ion >> channels open potassium ions exit leaving the inside more negative, >> while sodium is more concentrated outside the cell so when sodium >> channels open sodium ions enter making the inside more positive. The >> sodium and potassium fluxes are responsible for depolarisation, the >> action potential and repolarisation. There can't be an action >> potential without these ion fluxes, there can't be ion fluxes without >> the ion channels opening and closing, and the ion channels can't open >> and close without the appropriate voltage or neurotransmitter >> stimulus. Spontaneously active neurons have voltage-activated ion >> channels that open at the cell's resting potential. > > All of these processes supervene upon the spontaneous changes to > electromagnetic conditions. You are talking as if the brain is just a > sponge which fills up with electrolytes and discharges them regularly > without any control over the process. If you can move your finger > deliberately, then that means that the neurons associated with that > movement are also being depolarized intentionally - through sentience > and actively engaged teleology, not just passive inertia. You don't > have to keep reciting neurology 101 to me, I can read Wikipedia too. I have given a basic account of the electrophysiology of neurons because you don't seem to understand it, and you still don't, since you ask above "what changes the potential difference in the first place?" The membrane potential changes due to the balance of positive and negative ions, and the ions move passively by diffusion through the membrane and through ion channels and actively as the result of energy-dependent ion pumps such as sodium-potassium ATPase. You have misunderstood what spontaneous neural activity means. It doesn't mean that the neurons decide to choose coffee rather than tea and then depolarise their membranes accordingly. >> So at some point the psyche, not being the normal neural mechanisms, >> acts on the neurons and starts off the chain of events. Can you >> describe this further? What exactly happens in the neuron at the >> molecular level when the psyche acts? > > The neural mechanisms of a particular region of the brain are the > 'shadow' of the psyche - the 1-p / 3-p inflection point, like a 2D > Flatland slice of a 3D object (I assume you are familiar with this. > http://www.wardrobe-dweller.org.uk/Flatland.htm) which contains only a > small fraction of the phenomenology which intersects that 'plane'. > Whether those mechanisms are 'normal' or not depends how 'normal' the > subject feels. At no time will anything impossible occur on that 2D > plane, but the overall pattern of the 2D phenomena over time is > influenced by the progress of the 3D phenomena as it is revealed > dynamically over time, one moment at a time. > > When the psyche acts it works like an electrical transformer or > rectifier. Let's say that I am making a list of things that I like and > I decide that I like the Red Sox. What happens is that my feeling of > attraction to a (3D) complex of images, ideas, associations, and > experiences (baseball, Red, Boston, etc) manifested publicly (2D) as a > change in the charge of thousands of neurons at once in different > regions of the brain. It's like clenching and relaxing your fist. The > fingers move, the fingernails move with them, the dirt under the > fingernails moves with the fingernails, the atoms in the dirt move, > etc. It's all one energy event with a multitude of related > electromagnetic aspects and consequences. You haven't answered what you think actually happens at the molecular level in one of the neurons that spontaneously decides to depolarise. Do sodium channels distort without any force on them to let the ions through, do the sodium ions materialise out of nowhere, or what? -- Stathis Papaioannou -- You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to email@example.com. To unsubscribe from this group, send email to everything-list+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/everything-list?hl=en.