On Tue, Sep 27, 2011 at 7:01 AM, Craig Weinberg <whatsons...@gmail.com> wrote:
>> OK, so you agree that the *observable* behaviour of neurons can be >> adequately explained in terms of a chain of physical events. The >> neurons won't do anything that is apparently magical, right? > > Are not all of our observations observable behaviors of neurons? > You're not understanding how I think observation works. There is no > such thing as an observable behavior, it's always a matter of > observable how, and by who? If you limit your observation of how > neurons behave to what can be detected by a series of metal probes or > microscopic antenna, then you are getting a radically limited view of > what neurons are and what they do. You are asking a blind man what the > Mona Lisa looks like by having him touch the paint, then making a > careful impression of his fingers, and then announcing that the Mona > Lisa can only do what fingerpainting can do, and that inferring > anything beyond the nature of plain old paint to the Mona Lisa is > magical. No. It doesn't work that way. A universe where nothing more > than paint exists has no capacity to describe an intentional, higher > level representation through a medium of paint. The dynamics of paint > alone do not describe their important but largely irrelevant role to > creating the image. Observable behaviours of neurons include things such as ion gates opening, neurotransmitter release at the synapse and action potential propagation down the axon. I know there may also be non-observables, but I'm only asking about the observables. Do you agree that if a non-observable causes a change in an observable, that would be like magic from the point of view of a scientist? >> > We know that for example, gambling affects the physical behavior of >> > the amygdala. What physical force do you posit that emanates from >> > 'gambling' that penetrates the skull and blood brain barrier to >> > mobilize those neurons? >> >> The skull has various holes in it (the foramen magnum, the orbits, >> foramina for the cranial nerves) through which sense data from the >> environment enters and, via a series of neural relays, reaches the >> amygdala and other parts of the brain. > > What is 'sense data' made of and how does it get into 'gambling'? Sense data could be the sight and sound of a poker machine, which gets into the brain, is processed in a complex way, and is understood to be "gambling". > Not at all. The amygdala's response to gambling cannot be observed on > an MRI. We can only infer such a cause because we a priori understand > the experience of gambling. If we did not, of course we could not > infer any kind of association with neural patterns of firing with > something like 'winning a big pot in video poker'. That brain activity > is not a chain reaction from some other part of the brain. The brain > is actually responding to the sense that the mind is making of the > outside world and how it relates to the self. It is not going to be > predictable from whatever the amygala happens to be doing five seconds > or five hours before the win. The amygdala's response is visible on a fMRI, which is how we know about it. We can infer this without knowing anything about either gambling or the brain, noticing that input A (the poker machine) is consistently followed by output B (the amygdala lighting up on fMRI). >> You have not answered it. You have contradicted yourself by saying we >> *don't* observe the brain doing things contrary to physics and we *do* >> observe the brain doing things contrary to physics. > > We don't observe the Mona Lisa doing things contrary to the properties > of paint, but we do observe the Mona Lisa as a higher order experience > manifested through paint. It's the same thing. Physics doesn't explain > the psyche, but psyche uses the physical brain in the ordinary > physical ways that the brain can be used. But the Mona Lisa does not move of its own accord. That is what it would have to do for the situation to be analogous to brain changes occurring due to mental processes and not physical processes. >>You seem to >> believe that neurons in the amygdala will fire spontaneously when the >> subject thinks about gambling, which would be magic. > > You don't understand that you are arguing against neuroscience and > common sense. Of course you can manually control your electrochemical > circuits with thought. That's what all thinking is. It's not that the > amygdala fires spontaneously, it's that the thrills and chills of > risktaking *are* the firing of the amygdala. You seem to be saying > that the brain has our entire life planned out for us in advance as > some kind of meaningless encephalographic housekeeping exercise where > we have no ability to make ourselves horny by thinking about sex or > hungry by thinking about food, no capacity to do or say things based > upon the realities outside of our skull rather than the inside. I'm not sure if you're not understanding or just pretending not to understand. Take any neuron in the brain: it fires due to the influences of the surrounding neurons, and each of those neurons fires due to the influence of the neurons surrounding it, and so on, accounting for all the neurons in the brain. These are the third person observable effects; associated with (or identical to, or another aspect of, or supervening on, or a side-effect of - it doesn't change the argument) this observable activity are the thoughts and feelings. A scientist cannot see the thoughts and feelings, since they are non-observable. The non-observable thoughts and feelings cannot affect the observable physical activity, for if they could, the scientist would see apparently magical events. We can still say that thought A leads to feeling B, but what the scientist observes is that brain state A' (associated with thought A) leads to brain state B' (associated with feeling B). So although we can tell the story of the person in terms of thoughts and feelings, the scientist can tell the same story in terms of biochemical events. If the scientist understands the biochemistry then in theory he will be able to predict everything the person will do (or write probabilistic equations if truly random effects are significant in the brain), although in practice due to the complexity of the system this would be very difficult. >>Neurons only fire >> in response to a physical stimulus. > > Absurd. Is there a physical difference between a letter written in > Chinese and one written in English...some sort of magic neurochemical > that wafts off of the Chinese ink that prevents my cortex from parsing > the characters? Of course there is! The Chinese characters reflect light in a different pattern, which stimulates the retina differently, which sends different signals to the visual cortex, which sends different signals to the language centres. If knowledge of Chinese has been stored in the language centre the subject understands it, otherwise he does not. >> That the physical stimulus has >> associated qualia is not observable: >> a scientist would see the neuron >> firing, explain why it fired in physical terms, and then wonder as an >> afterthought if the neuron "felt" anything while it was firing. > > Which is why that approach is doomed to failure. There is no point to > the brain other than to help process qualia. Very little of the brain > is required for a body to survive. Insects have brains, and they > survive quite well. That the scientist can't see the qualia is not his fault. As a practical matter, knowledge of the mechanics of the brain can help in restoring normal function when things go wrong, even without understanding the qualia. >> >> A neuron has a limited number of duties: to fire if it sees a certain >> >> potential difference across its cell membrane or a certain >> >> concentration of neurotransmitter. >> >> > That is a gross reductionist mispresentation of neurology. You are >> > giving the brain less functionality than mold. Tell me, how does this >> > conversation turn into cell membrane potentials or neurotransmitters? >> >> Clearly, it does, since this conversation occurs when the neurons in >> our brains are active. > > My God. You are unbelievable. I give you a straightforward, unarguably > obvious example of a phenomenon which obviously has absolutely nothing > to do with cellular biology but is nonetheless controlling the > behavior of neurological cells, and you answer that that it must be > biological anyways. Your position, literally, is that 'I can't be > wrong, because I already know that I am right.' Particular brain activity is necessary and sufficient for this conversation to occur. It is necessary because without this brain activity, no conversation. It is sufficient because if this brain activity occurs, the conversation occurs. These are mainstream scientific beliefs which are not disputed, like the fact that the heart pumps blood. >>The important functionality of the neurons is >> the action potential, since that triggers other neurons and ultimately >> muscle. The complex cellular apparatus in the neuron is there to allow >> this process to happen, as the complex cellular apparatus in the >> thyroid is to enable secretion of thyroxine. An artificial thyroid >> that measured TSH levels and secreted thyroxine accordingly could >> replace the thyroid gland even though it was nothing like the original >> organ in structure. > > But you have no idea what triggers the action potentials in the first > place other than other action potentials. This makes us completely > incapable of any kind of awareness of the outside world. You are > mistaking the steering wheel for the driver. The outside world gets in via the sense organs, which trigger action potentials in nerves, which then trigger a series of action potentials in the brain. >> > So if I move my arm, that's because the neurons that have nothing to >> > do with my arm must have caused the ones that do relate to my arm to >> > fire? And 'I' think that I move 'my arm' because why exactly? >> >> The neurons are connected in a network. If I see something relating to >> the economy that may lead me to move my arm to make an online bank >> account transaction. > > What is 'I' and how does it physically create action potentials? The > whole time you are telling me that only neurons can trigger other > neurons, and now you want to invoke 'I'? Does I follow the laws of > physics or is it magic? Which is it? Does 'I' do anything that cannot > be explained by action potentials and cerebrospinal fluid? I expect > I'm going to hear some metaphysical invocations of 'information' in > the network. "I" am the ensemble of neurons in the brain which when they are functioning properly give rise to consciousness and a sense of identity. "I" never do anything that can't be explained in terms of a chain of neuronal events. >> Obviously there has to be some causal connection >> between my arm and the information about the economy. How do you >> imagine that it happens? > > It happens because you make sense of the what you read about the > economy and that sense motivates you to instantiate your own arm > muscles to move your arm. The experience making sense of the economic > news, as you said, *may* lead 'you' to move your arm - not *will > cause* your arm to move, or your neurons to secrete acetylcholine by > itself. It's a voluntary, high level, top-down participation through > which you control your body and your life. The making sense of what you read occurs due to certain neuronal activity in the language centre of your brain. This may or may not cause you to take a certain action, just as a coin may come up heads or tails. >> > If the brain of even a flea were anywhere remotely close to the >> > simplistic goofiness that you describe, we should have figured out >> > human consciousness completely 200 years ago. >> >> Even the brain of a flea is very complex. The brain of the nematode C >> elegans is the simplest brain we know, and although we have the >> anatomy of its neurons and their connections, no adequate computer >> simulation exists because we do not know the strength of the >> connections. > > Why is the strength of the connections so hard to figure out? Because scientific research is difficult. >> There is a certain level of tolerance in every physical object we >> might want to simulate. We need to know a lot about it, but we don't >> need accuracy down to the position of every atom, for if the brain >> were so delicately balanced it would malfunction with the slightest >> perturbation. > > A few micrograms of LSD or ricin can change a person's entire life or > end it. Yes, there are crucial parts of the system which don't tolerate disruption. It's the same with any machine. >> Whether something is conscious or not has nothing to do with whether >> it is deterministic or predictable. > > What makes you think that's true? Do you have a counterfactual? There is no reason to believe that determinism affects consciousness. In general it is impossible to distinguish random from pseudorandom. If the brain utilised true random processes and part of it were replaced with a component that used a pseudorandom number generator with a similar probability function to the true random one we would notice no change in behaviour and the subject would notice no change in consciousness (for if he did there would be a change in behaviour). >> This statement shows that you haven't understood what a partial zombie >> is. It is a conscious being which lacks consciousness in a particular >> modality, such as visual perception or language processing, but does >> not notice that anything is abnormal and presents no external evidence >> that anything is abnormal. You have said a few posts back that you >> think this is absurd: when you're conscious, you know you're >> conscious. > > I can only use examples where the partial zombie is on the outside > rather than the inside, since there is no way to have an example like > that (you either can't tell if someone else is a zombie or you can't > tell anything if you yourself are a partial zombie). I understand > exactly what you are saying, I'm just illustrating that if you turn it > around so that we can see the zombie side out but assume a non-zombie > side inside, it's the same thing, and that it's no big deal. A partial zombie occurs if only part of your brain is zombified. Because this part of the brain (by definition) has the same observable third person behaviour as it did before it was zombified, you would lack the qualia of the replaced part while not noticing or behaving differently. It is this which is absurd. The only way out of the absurdity is to say that it is impossible to make a brain component with the same observable third person behaviour that didn't also have the same qualia. (Sorry for the clumsiness of "observable third person behaviour" - I should just say "behaviour" but I think in the past you have taken this to include consciousness). >> The question is, why did humans evolve with consciousness rather than >> as philosophical zombies? The answer is, because it isn't possible to >> make a philosophical zombie since anything that behaves like a human >> must be conscious as a side-effect. > > I understand that you are able to take that argument seriously, but it > just jaw dropping to me that anyone could. Why does fire exist? > Because it isn't possible to burn anything without starting a fire > because anything that behaves like it's on fire must be burning as a > side effect. It's just the most nakedly fallacious non-explanation I > can imagine. It has zero explanatory power, and besides that, it's > completely untrue. An actor's presence in a movie behaves like a human > but the image on the screen is not 'conscious as a side-effect'. They > are not even a little bit more conscious than a picture of a circle. > Just, ugh. Consciousness is a rather elaborate thing to evolve and elaborate things like that don't evolve unless they strongly enhance survival and reproductive success. If philosophical zombies were possible, they would have the same survival and reproductive success as non-zombies. But philosophical zombies did not evolve, suggesting to me that consciousness is a necessary side-effect of any intelligent being. >> It's not impossible, there is a qualitative difference between >> difficult and impossible. It would be difficult for humans to build a >> planet the size of Jupiter, but there is no theoretical reason why it >> could not be done. On the other hand, it is impossible to build a >> square triangle, since it presents a logical contradiction. There is >> no logical contradiction in substituting the function of parts of the >> human body. Substituting one thing for another to maintain function is >> one of the main tasks to which human intelligence is applied. > > I understand what you are saying, and I would agree with you if the > contents of the psyche were not so utterly different from the physical > characteristics of the brain. We have no precedent for engineering > such a thing. It dwarfs the idea of building Jupiter. If you say we > can substitute lead for gold, I would say, well, sure, if you blast it > down to protons and reassemble it atom by atom - or find an easier way > to do it with a particle accelerator. But we have no common > denominator of human consciousness to work from. A few micrograms off > here or chromosomes off there, and you get major changes. I'm much > more optimistic about replicating tissue, and augmenting the nervous > system, but actually replacing it and expecting 'you' to still be in > there is a completely different proposition. We have already started engineering brain replacement: cochlear implants, artificial hippocampus. These are crude but it's early days yet. >> You're saying that free will in a deterministic world is >> contradictory. That may be the case if you define free will in a >> particular way (and not everyone defines it that way), but still that >> does not imply that the *feeling* of free will is incompatible with >> determinism. > > I think that it is, because determinism assumes that everything that > happens happens for a particular reason. What would the reason for > such a feeling to exist, and how would it come into existence? Why > would determinism care if something pretends that it is not > determined, and how could it even ontologically conceived of non- > determined? The feeling of free will is simply due to the fact that I don't know what I'm going to do until I do it. This is the case for computer programs as well: the program can't know what the outcome of the computation is until it actually runs, otherwise running it would be a waste of time. -- 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.