RE: where do copies come from?
Brent Meeker writes: [quoting Stathis Papaioannou] In the case of the heart the simpler artificial pump might be just as good, but in the case of a brain, the electrical activity of each and every neuron is intrinsically important in the final result. That last seems extremely dubious. What evidence is there for it? They're completely different things: one is information processing, the other is... pumping. If we went back to ancient Greece, we could do much better in terms of transportation than horses and chariots, but if we wanted to know what was in the Iliad and the Odyssey, we would have to copy, word for word, what the ancient manuscripts said, even if we decided to put the whole thing on a hard disk as a text file or whatever. It's not that there is anything special about papyrus; Homer would probably have used a computer if he had one, especially since he was blind. But just as we have to pay loving attention to the crumbly old ancient documents if we want to know what they said, so we have to pay loving attention to the crumbly old neurons if we want to know what *they* say, before transferring their contents to a more modern and durable medium. --Stathis Papaioannou _ Dating? Try Lavalife get 7 days FREE! Sign up NOW. http://www.lavalife.com/clickthru/clickthru.act?id=ninemsncontext=an99a=20233locale=en_AU_t=33473
Re: where do copies come from?
On Mon, Jul 11, 2005 at 10:38:35PM -0700, George Levy wrote: Stathis Papaioannou wrote: The ionic gradients across cell membranes determine the transmembrane potential and how close the neuron is to the voltage threshold which will trigger an action potential by opening transmembrane ion Stop your heart now. See EEG collapse to zero in 20-30 sec. Your transient gradients (spikes) are gone with the oxygen, until circulation is restored. All you see is a brief blackout. I wonder for whom I'm writing all these mails. channels. Other factors influencing this include the exact geometry of the neuron and composition of the cell membrane (which determines capacitance and the shape and speed of propagation of the action potential), the number, type and location of voltage-activated ion channels, the number, type and location of various neurotransmitter receptors, the local concentration of enzymes that break down neurotransmitters, and many other things besides. The ionic gradients You might be surprised: http://www.google.com/search?hl=enq=computational+neurosciencebtnG=Google+Search across cell membranes (all cell membranes, not just neurons) are actively maintained within tight limits by energy-requiring transmembrane proteins, such as Na/K ATPase, and if this suddenly stops working, the cell will quickly die. The moment to moment Define quickly. You can culture human neurons for several days after death. At deep hypothermia and flushout, the empirical canine viability window is several hours (the ceiling could be at 12 h or more, nobody knows yet). http://groups.yahoo.com/group/transhumantech/message/29582 variations in ion fluxes and membrane potential may be allowed to collapse and the neuron will remain structurally intact, so to this extent the exact cellular chemistry may not be necessary for long term You can safely remove the conditional here. memories. However, all the other things I have mentioned are important in determining the wiring diagram and strength of connections, and could easily be maintained over decades. Look up action potential in Yes, and all of them seem to be present in vitrified brain tissue -- a snapshot with geological shelf half-life. Wikipedia, and think about how you would design an equivalent circuit for even one neuron. It may be a ridiculously complex way to design a You don't design a circuit for a specific neuron. That would be moot, as a circuit is fixed, and a neuron is not (an understatement: see cell migration in neuromorphogenesis). What you need is a computational engine capable of emulating arbitrary cells in the CNS. The hardware layer of such a system can be very simple, the complexity being contained in several emulation layers. computer that would be able to run and maintain a human body, but whereas I would happily trade my heart or my kidneys for more efficiently engineered models, I would like any brain replacement to be an exact functional analogue of my present one. Nobody is trying to sell anything else. Stathis, you don't have to get down to that level of complexity. As long as the high level function remains the same, you can still say yes doctor to a substitution experiment. Example: artificial eye lenses made of plastic and not of tissue, prostheses made of titanium steel and not of bone. I seem to not be coming through, so this will be the last post on my part in this thread, for a long while. -- Eugen* Leitl a href=http://leitl.org;leitl/a __ ICBM: 48.07100, 11.36820http://www.leitl.org 8B29F6BE: 099D 78BA 2FD3 B014 B08A 7779 75B0 2443 8B29 F6BE signature.asc Description: Digital signature
Re: where do copies come from?
On Mon, Jul 11, 2005 at 10:31:56AM +1000, Stathis Papaioannou wrote: Perhaps, perhaps not. For one thing, in the brain's case we are relying on the laws of chemistry and physics, which in the real world are invariable; we don't know what would happen if these laws were slightly off in a A systematic error or noise beyond the homeostatic capability of the simulation would generate nonsense, of course. So, stay below the error threshold. simulation. For another, we do know that tiny chemical changes, such as a few molecules of LSD, can make huge behavioural changes, suggesting that the brain is exquisitely sensitive to at least some parameters. It is So, don't put LSD in the simulated brain. Don't zap the CMOS junction with electrostatics. Don't put the system nearby a Co-60 source. Do not mutate bits randomly. Do not change the meaning of a primitive randomly every few ticks. If it hurts, don't do it. likely that multiple error correction and negative feedback systems are in place to ensure that small changes are not chaotically amplified to cause gross mental changes after a few seconds, and all these systems would have to be simulated as well. The end result may be that none of the cellular Of course. And your point is? machinery can be safely ignored in an emulation, which is very far from modelling the brain as a neural net. I may be wrong, and it may be simpler Strawman, again. than I suggest, but as a general rule, if there were a simpler and more economical way to do things, evolution would have found it. Biological tissues are not evolved to e.g. work with EM radio, or electron spin for information processing, or nuclear fission for power sources, or an enzyme to deposit diamond. Regardless how many gigayears you spend evolving, this will never be discovered due to kinetic blocks, fitness crevices, and sterile areas in fitness space which can't be crossed incrementally. Human design doesn't have that limitation. We can in principle do whatever evolution can do (by explicitly invoking the process, in an accelerated model), and more. The fitness function of discrete information processing in solid state is entirely different from CNS. Most of what the genome does is not devoted to neural information processing, and, frankly anisotropically excitable nonlinear medium is a control paradigm from hell. There are simpler and more economical ways to do things, and we'll be there in about 20-30 years. Meanwhile, biology reigns supreme in crunch/Joule, integration density, error tolerance and a few other things, but we're gaining on it rapidly. -- Eugen* Leitl a href=http://leitl.org;leitl/a __ ICBM: 48.07100, 11.36820http://www.leitl.org 8B29F6BE: 099D 78BA 2FD3 B014 B08A 7779 75B0 2443 8B29 F6BE signature.asc Description: Digital signature
Re: where do copies come from?
Eugen Leitl writes: likely that multiple error correction and negative feedback systems are in place to ensure that small changes are not chaotically amplified to cause gross mental changes after a few seconds, and all these systems would have to be simulated as well. The end result may be that none of the cellular Of course. And your point is? machinery can be safely ignored in an emulation, which is very far from modelling the brain as a neural net. I may be wrong, and it may be simpler Strawman, again. than I suggest, but as a general rule, if there were a simpler and more economical way to do things, evolution would have found it. Biological tissues are not evolved to e.g. work with EM radio, or electron spin for information processing, or nuclear fission for power sources, or an enzyme to deposit diamond. Regardless how many gigayears you spend evolving, this will never be discovered due to kinetic blocks, fitness crevices, and sterile areas in fitness space which can't be crossed incrementally. Human design doesn't have that limitation. We can in principle do whatever evolution can do (by explicitly invoking the process, in an accelerated model), and more. The fitness function of discrete information processing in solid state is entirely different from CNS. Most of what the genome does is not devoted to neural information processing, and, frankly anisotropically excitable nonlinear medium is a control paradigm from hell. There are simpler and more economical ways to do things, and we'll be there in about 20-30 years. Meanwhile, biology reigns supreme in crunch/Joule, integration density, error tolerance and a few other things, but we're gaining on it rapidly. There is a fundamental difference between copying evolution's version of, say, a pump, and a brain. The whole complex business of excitable cardiac muscle cells beating in synchrony with a pacemaker need not be emulated, of course, if you are just trying to build an efficient artificial heart. If the purpose is just to pump, what may have been necessary for nature is superfluous for an engineer. On the other hand, with a brain, all the elaborate detail is intrinsically important: the engineer doesn't just want to build an efficient processor which will keep the human body going, but to copy the *actual* processor, however needlessly complex. But perhaps I should end this thread by admitting that I was not aware that there were mind uploaders out there seriously contemplating the emulation of a brain down to the molecular level, and express my astonishment, which hopefully will turn into admiration, at your 20-30 year time span for completing such a project. --Stathis Papaioannou _ REALESTATE: biggest buy/rent/share listings http://ninemsn.realestate.com.au
RE: where do copies come from?
-Original Message- From: Stathis Papaioannou [mailto:[EMAIL PROTECTED] Sent: Friday, July 08, 2005 6:33 AM To: [EMAIL PROTECTED] Cc: everything-list@eskimo.com Subject: RE: where do copies come from? Brent Meeker writes: I find it hard to believe that something as stable as memories that last for decades is encoded in a way dependent on ionic gradients across cell membranes and the type, number, distribution and conformation of receptor and ion channel proteins. What evidence is there for this? It seems much more likely that long term memory would be stored as configuration of neuronal connections. You have to keep in mind that every living organism is being continually remodelled by cellular repair mechanisms. Jesse Mazer recently quoted an article which cited radiolabelling studies demonstrating that the entire brain is turned over every couple of months, and the synapses in particular are turned over in a matter of minutes. The appearance of permanent anatomical structures is an illusion due to the constant expenditure of energy rebuilding that which is constantly falling apart. So? I don't see the point of this observation. If the structure is maintained, then the structure *is* permanent and is suitable for storing long term memories. The fact that the physical elements of the structure are replaced every five seconds or every ten years is neither here or nor there. If anything, parameters such as ionic gradients and protein conformation are more closely regulated over time than gross anatomy. Gradients where? Surely you aren't saying that there is a pattern of gradients in the brain that is relative to (x,y,z) coordinates and is independent of the neuronal structures. Cancer cells may forget who they are, what their job is, what they look like and where they live, but if an important enzyme curled up a little tighter than usual due to corruption of intracellular homeostasis mechanisms, the cell would instantly die. I doubt that any memories are stored in intracelluar chemistry. Recent theory based on the work of Eric Kandel is that long term memory is mediated by new protein synthesis in synapses, which modulates the responsiveness of the synapse to neurotransmitter release; that is, it isn't just the wiring diagram that characterises a memory, but also the unique properties of each individual connection. I would not have supposed otherwise. I would guess that memories are stored as they are in artificial neural networks: in the wiring diagram PLUS the strength of the connections. But let's suppose, for the sake of argument, that each distinct mental state were encoded by the simplest possible mechanism: the on or off state of each individual neuron. This would allow 2^10^11 possible different mental states - more than enough for trillions of humans to live trillions of lifetimes and never repeat a thought. Yes, I'm well aware that a brain is really really complicated. In theory, it should be possible to scan a brain in vivo using some near-future MRI analogue and determine the state of each of the 10^11 neurons, and store the information as a binary srtring on a hard disk. Once we had this data, what would we do with it? The details of ionic gradients, type, number and conformation of cellular proteins, But what is the evidence that these play are part in long term memory? anatomy and type of synaptic connections, That's wiring diagram and strength of connections. etc. etc. etc., would be needed for each neuron, along with an accurate model of how they all worked and interacted, in order to calculate the next state, and the state after that, and so on. But calculating the next state corresponds to continuing consciousness without a gap. That I agree would require simulating all the gradients, etc, down to near molecular level. But my original contention was that you could simulate a person, with a memory gap such as incurred under anesthesia, by just the wiring diagram plus strength of connnections. This would be difficult enough to do if each neuron were considered in isolation, but in fact, there may be hundreds of synaptic connections between neurons, and the activity of each connected neuron needs to be taken into account, along with the activity of each of the hundreds of neurons connected to each of *those* neurons, and so on. Sure - but that's still wiring diagram. I didn't say it was simple; but it's a lot simpler than trying to capture the instantaneous chemistry. Brent Meeker
RE: where do copies come from?
Brent Meeker writes: I find it hard to believe that something as stable as memories that last for decades is encoded in a way dependent on ionic gradients across cell membranes and the type, number, distribution and conformation of receptor and ion channel proteins. What evidence is there for this? It seems much more likely that long term memory would be stored as configuration of neuronal connections. If anything, parameters such as ionic gradients and protein conformation are more closely regulated over time than gross anatomy. Gradients where? Surely you aren't saying that there is a pattern of gradients in the brain that is relative to (x,y,z) coordinates and is independent of the neuronal structures. The ionic gradients across cell membranes determine the transmembrane potential and how close the neuron is to the voltage threshold which will trigger an action potential by opening transmembrane ion channels. Other factors influencing this include the exact geometry of the neuron and composition of the cell membrane (which determines capacitance and the shape and speed of propagation of the action potential), the number, type and location of voltage-activated ion channels, the number, type and location of various neurotransmitter receptors, the local concentration of enzymes that break down neurotransmitters, and many other things besides. The ionic gradients across cell membranes (all cell membranes, not just neurons) are actively maintained within tight limits by energy-requiring transmembrane proteins, such as Na/K ATPase, and if this suddenly stops working, the cell will quickly die. The moment to moment variations in ion fluxes and membrane potential may be allowed to collapse and the neuron will remain structurally intact, so to this extent the exact cellular chemistry may not be necessary for long term memories. However, all the other things I have mentioned are important in determining the wiring diagram and strength of connections, and could easily be maintained over decades. Look up action potential in Wikipedia, and think about how you would design an equivalent circuit for even one neuron. It may be a ridiculously complex way to design a computer that would be able to run and maintain a human body, but whereas I would happily trade my heart or my kidneys for more efficiently engineered models, I would like any brain replacement to be an exact functional analogue of my present one. --Stathis Papaioannou _ Dont just search. Find. Check out the new MSN Search! http://search.msn.click-url.com/go/onm00200636ave/direct/01/
Re: where do copies come from?
Stathis Papaioannou wrote: The ionic gradients across cell membranes determine the transmembrane potential and how close the neuron is to the voltage threshold which will trigger an action potential by opening transmembrane ion channels. Other factors influencing this include the exact geometry of the neuron and composition of the cell membrane (which determines capacitance and the shape and speed of propagation of the action potential), the number, type and location of voltage-activated ion channels, the number, type and location of various neurotransmitter receptors, the local concentration of enzymes that break down neurotransmitters, and many other things besides. The ionic gradients across cell membranes (all cell membranes, not just neurons) are actively maintained within tight limits by energy-requiring transmembrane proteins, such as Na/K ATPase, and if this suddenly stops working, the cell will quickly die. The moment to moment variations in ion fluxes and membrane potential may be allowed to collapse and the neuron will remain structurally intact, so to this extent the exact cellular chemistry may not be necessary for long term memories. However, all the other things I have mentioned are important in determining the "wiring diagram and strength of connections", and could easily be maintained over decades. Look up "action potential" in Wikipedia, and think about how you would design an equivalent circuit for even one neuron. It may be a ridiculously complex way to design a computer that would be able to run and maintain a human body, but whereas I would happily trade my heart or my kidneys for more efficiently engineered models, I would like any brain replacement to be an exact functional analogue of my present one. Stathis, you don't have to get down to that level of complexity. As long as the high level function remains the same, you can still say "yes doctor" to a substitution experiment. Example: artificial eye lenses made of plastic and not of tissue, prostheses made of titanium steel and not of bone. George
Re: where do copies come from?
On Sun, Jul 10, 2005 at 11:49:53PM +1000, Stathis Papaioannou wrote: 3) Combining General and Particular Architectures Fusing information to combine apriori knowledge of general architecture brain functions, and particular architecture data obtained from in situ functional measurements (e.g. fMRI), neurological and psychological measurements, as well as self-analysis, it may be possible to reconstruct a functional copy of the brain close enough as to be indinstinguishable from the original by the owner. How does the owner knows it is indistinguishable? This is a whole topic. He could for example do a series of partial substitutions to find out if it feels the same or not. For example, he could substitute in sequence the visual cortex, the auditory cortex, some of the motor functions We may be closer to this goal than you think. OK, I agree it is possible, and I'm glad nobody is insisting that just the arrangement of neurons and their connections, such as could in theory have been determined by a 19th century histologist, is enough information to Exactly; it's a strawman position. Nobody claims a 5 m resolution satellite photo shows you what brands of pizza that shop on the corner is selling. emulate a brain. I think we would need to have scanning resolution close to the atomic level, and very detailed modelling of the behaviour of cellular subsystems and components down to the same level. I don't know how long it You need this level of detail only initially, to obtain empiric system parameters for an abstracted system level. You might want to reach down to ab initio level of theory, to obtain missing parameters for an MD simulation, to obtain switching behaviour of an ion channel, depending on modification, to obtain computational behaviour of a piece of dendrite (of course, you can also obtain that empirically from e.g. voltage-sensitive dye/patch-clamping). Even then, the actual simulation unit could be a few layers up, at abstract neocortex columns, or similiar. In the end, you have to destructively scan an animal to obtain your very large set of numbers, to enter into your simulation. Transiently, that disassembly might involve sampling some voxels at a high level of resolution, very possibly submolecular. That level of detail might be present in the voxel buffer, transiently, before being processed by algorithms, and destilled into a much smaller set of small integers. would take to achieve this, but I know that we are nowhere near it now. For example, consider our understanding of schizophrenia, an illness which If we had fully functional (discrete, fully introspective, traceable) models of individuals having schizophrenia, and controls, finding structural and functional deficits resulting in the phenotype would be effectively trivial. drastically changes almost every aspect of cognition. For half a century we have had drugs which ameliorate the psychotic symptoms patients with this illness experience, and we have been able to determine which receptors these drugs target. But despite decades of research, we still have no idea what the basic defect in schizophrenia is, how the drugs work, or any We don't have methods with sufficient resolution, that's all. clinically useful investigation which helps with diagnosis. Although fMRI and PET scans can show differences in cerebral blood flow compared to fMRI has voxel sizes at several mm^3, and temporal resolution of seconds. MRI microscopy does much better, but only works on insect/mouse-sized samples. Nondestructive methods do not scale into the volume. control subjects, this is a secondary effect. The brains of schizophrenia sufferers, looked at with any tools available to us, are essentially the same as normal brains. In other words, a very subtle, at present undetectable, change in the brains of these patients can cause gross cognitive and behavioural changes. http://www.google.com/search?num=100hl=enlr=safe=offclient=firefox-arls=org.mozilla%3Aen-US%3Aofficialq=molecular+schizophreniabtnG=Search would seem to disagree. -- Eugen* Leitl a href=http://leitl.org;leitl/a __ ICBM: 48.07100, 11.36820http://www.leitl.org 8B29F6BE: 099D 78BA 2FD3 B014 B08A 7779 75B0 2443 8B29 F6BE signature.asc Description: Digital signature
RE: where do copies come from?
Stathis Papaioannou wrote: Nevertheless, I still think it would be *extremely* difficult to emulate a whole brain. Just about every physical parameter for each neuron would be relevant, down to the atomic level. If any of these parameters are slightly off, or if the mathematical model is slightly off, the behaviour of a single neuron may seem to be unaffected, but the error will be amplified enormously by the cascade as one neuron triggers another. I don't think that follows. After all, we maintain the same personality despite the fact that these detailed parameters are constantly varying in our own neurons (and the neurons themselves are being completely replaced every few months or so); neural networks are not that brittle, they tend to be able to function in broadly the same way even when damaged in various ways, and slight imperfections in the simulated behavior of individual neurons could be seen as a type of damage. As long as the behavior of each simulated neuron is close enough to how the original neuron would have behaved in the same circumstances, I don't think occasional slight deviations would be fatal to the upload (but perhaps the first uploads will act like people who are slightly drunk or have a chemical imbalance or something, and they'll have to experiment with tweaking various high-level parameters--the equivalent of giving themselves simulated prozac or something--until they feel 'normal' again). Jesse
Re: where do copies come from?
I agree with Jesse. Nature (if that exists) build on redundancies. (As the UD). So if the substitution level is at the neural neurons, ``slight changes don't matter. Of course we don't really know our substitution level. It is consistent with comp the level is far lower. But then at that level the same rule operates. It probably converges to the linear. Bruno (PS: I will answer other posts asap). Le 10-juil.-05, à 20:22, Jesse Mazer a écrit : Stathis Papaioannou wrote: Nevertheless, I still think it would be *extremely* difficult to emulate a whole brain. Just about every physical parameter for each neuron would be relevant, down to the atomic level. If any of these parameters are slightly off, or if the mathematical model is slightly off, the behaviour of a single neuron may seem to be unaffected, but the error will be amplified enormously by the cascade as one neuron triggers another. I don't think that follows. After all, we maintain the same personality despite the fact that these detailed parameters are constantly varying in our own neurons (and the neurons themselves are being completely replaced every few months or so); neural networks are not that brittle, they tend to be able to function in broadly the same way even when damaged in various ways, and slight imperfections in the simulated behavior of individual neurons could be seen as a type of damage. As long as the behavior of each simulated neuron is close enough to how the original neuron would have behaved in the same circumstances, I don't think occasional slight deviations would be fatal to the upload (but perhaps the first uploads will act like people who are slightly drunk or have a chemical imbalance or something, and they'll have to experiment with tweaking various high-level parameters--the equivalent of giving themselves simulated prozac or something--until they feel 'normal' again). Jesse http://iridia.ulb.ac.be/~marchal/
Re: where do copies come from?
Hi stathis, Le Dimanche 10 Juillet 2005 13:22, Stathis Papaioannou a écrit : Nevertheless, I still think it would be *extremely* difficult to emulate a whole brain. while I agree with you about the difficulty to emulate a brain that already exists (such as emulate you or me for example), I don't think it is as such difficult as to emulate a conscious being. I remenber not so long ago the project mindpixel which was about to learn the common sense to a machine. I do think that passing the turing test is possible, and if it is one day succesfully passed by a machine (and not once but several time), It will be a proof that we are indeed turing emulable... if it is so, Bruno's theory will not be far from the truth ;) Quentin
RE: where do copies come from?
Jesse Mazer wrote: [quoting Stathis Papaioannou] Nevertheless, I still think it would be *extremely* difficult to emulate a whole brain. Just about every physical parameter for each neuron would be relevant, down to the atomic level. If any of these parameters are slightly off, or if the mathematical model is slightly off, the behaviour of a single neuron may seem to be unaffected, but the error will be amplified enormously by the cascade as one neuron triggers another. I don't think that follows. After all, we maintain the same personality despite the fact that these detailed parameters are constantly varying in our own neurons (and the neurons themselves are being completely replaced every few months or so); neural networks are not that brittle, they tend to be able to function in broadly the same way even when damaged in various ways, and slight imperfections in the simulated behavior of individual neurons could be seen as a type of damage. As long as the behavior of each simulated neuron is close enough to how the original neuron would have behaved in the same circumstances, I don't think occasional slight deviations would be fatal to the upload... Perhaps, perhaps not. For one thing, in the brain's case we are relying on the laws of chemistry and physics, which in the real world are invariable; we don't know what would happen if these laws were slightly off in a simulation. For another, we do know that tiny chemical changes, such as a few molecules of LSD, can make huge behavioural changes, suggesting that the brain is exquisitely sensitive to at least some parameters. It is likely that multiple error correction and negative feedback systems are in place to ensure that small changes are not chaotically amplified to cause gross mental changes after a few seconds, and all these systems would have to be simulated as well. The end result may be that none of the cellular machinery can be safely ignored in an emulation, which is very far from modelling the brain as a neural net. I may be wrong, and it may be simpler than I suggest, but as a general rule, if there were a simpler and more economical way to do things, evolution would have found it. --Stathis Papaioannou _ SEEK: Over 80,000 jobs across all industries at Australia's #1 job site. http://ninemsn.seek.com.au?hotmail
Re: where do copies come from?
Quentin Anciaux writes: Nevertheless, I still think it would be *extremely* difficult to emulate a whole brain. while I agree with you about the difficulty to emulate a brain that already exists (such as emulate you or me for example), I don't think it is as such difficult as to emulate a conscious being. I remenber not so long ago the project mindpixel which was about to learn the common sense to a machine. I do think that passing the turing test is possible, and if it is one day succesfully passed by a machine (and not once but several time), It will be a proof that we are indeed turing emulable... if it is so, Bruno's theory will not be far from the truth ;) I agree: it will be *far* easier to build a conscious machine than to emulate a particular brain, just as it is far easier to build a pump than an exact, cell for cell analogue of a human heart. In the case of the heart the simpler artificial pump might be just as good, but in the case of a brain, the electrical activity of each and every neuron is intrinsically important in the final result. --Stathis Papaioannou _ REALESTATE: biggest buy/rent/share listings http://ninemsn.realestate.com.au
Re: where do copies come from?
Stathis Papaioannou wrote: It is likely that multiple error correction and negative feedback systems are in place to ensure that small changes are not chaotically amplified to cause gross mental changes after a few seconds, On the other hand, the above may be precisely how consciousness operates! Picture a system that traverses through many different states as chaotic attractor cycles, and outside stimuli act to nudge the system between grossly different chaotic attractors. You have a system that needs to be exquisitely tuned to subtle input changes, yet also robust in the face of other types of changes (damage, etc.) In the brain, these state trajectories would be neuronal firing patterns and synaptic chemical gradients. Determining the chaotic attractors themselves would be neuronal morphology and ion channel types and locations. The short-term information about a brain might not need to be stored in order to reconstruct a brain. That is, individual neuron on-off states and synaptic chemical gradients may be how you feel and what you are thinking this moment--but discarding (or not measuring) this info might only mean the reconstructed brain would start from some blank state. Chaotic attractor dynamics would pull the system into one of the aforementioned chaotic cycles and the system as a whole would eventually recreate the short-term firing patterns and chemical gradients needed for normal functioning. (The above might be wrong in particulars, but I strongly suspect the concept of small changes perturbing a chaotic system to shift between chaotic attractors will play a role in the ultimate explanation of how neuronal processes give rise to conscious experience.) -Johnathan
Re: where do copies come from?
Dear Johnathan, I find this idea to be very appealing! It seesm to imply that consciousness per say has more to do with the attractor in state space that any particular tableaux of neutron firings. This, of course, would not fit well with the material eliminativists to be forced to extend the same ontological status that we extend to flesh and blood and hardware and electromagnetic fields to such entities as strange attractors ! ;-) http://www.newdualism.org/papers/M.Robertson/churchl.pdf Kindest regards, Stephen - Original Message - From: Johnathan Corgan [EMAIL PROTECTED] To: Stathis Papaioannou [EMAIL PROTECTED] Cc: [EMAIL PROTECTED]; everything-list@eskimo.com Sent: Sunday, July 10, 2005 10:48 PM Subject: Re: where do copies come from? Stathis Papaioannou wrote: It is likely that multiple error correction and negative feedback systems are in place to ensure that small changes are not chaotically amplified to cause gross mental changes after a few seconds, On the other hand, the above may be precisely how consciousness operates! Picture a system that traverses through many different states as chaotic attractor cycles, and outside stimuli act to nudge the system between grossly different chaotic attractors. You have a system that needs to be exquisitely tuned to subtle input changes, yet also robust in the face of other types of changes (damage, etc.) In the brain, these state trajectories would be neuronal firing patterns and synaptic chemical gradients. Determining the chaotic attractors themselves would be neuronal morphology and ion channel types and locations. The short-term information about a brain might not need to be stored in order to reconstruct a brain. That is, individual neuron on-off states and synaptic chemical gradients may be how you feel and what you are thinking this moment--but discarding (or not measuring) this info might only mean the reconstructed brain would start from some blank state. Chaotic attractor dynamics would pull the system into one of the aforementioned chaotic cycles and the system as a whole would eventually recreate the short-term firing patterns and chemical gradients needed for normal functioning. (The above might be wrong in particulars, but I strongly suspect the concept of small changes perturbing a chaotic system to shift between chaotic attractors will play a role in the ultimate explanation of how neuronal processes give rise to conscious experience.) -Johnathan
RE: where do copies come from?
Brent Meeker writes: I find it hard to believe that something as stable as memories that last for decades is encoded in a way dependent on ionic gradients across cell membranes and the type, number, distribution and conformation of receptor and ion channel proteins. What evidence is there for this? It seems much more likely that long term memory would be stored as configuration of neuronal connections. You have to keep in mind that every living organism is being continually remodelled by cellular repair mechanisms. Jesse Mazer recently quoted an article which cited radiolabelling studies demonstrating that the entire brain is turned over every couple of months, and the synapses in particular are turned over in a matter of minutes. The appearance of permanent anatomical structures is an illusion due to the constant expenditure of energy rebuilding that which is constantly falling apart. If anything, parameters such as ionic gradients and protein conformation are more closely regulated over time than gross anatomy. Cancer cells may forget who they are, what their job is, what they look like and where they live, but if an important enzyme curled up a little tighter than usual due to corruption of intracellular homeostasis mechanisms, the cell would instantly die. Recent theory based on the work of Eric Kandel is that long term memory is mediated by new protein synthesis in synapses, which modulates the responsiveness of the synapse to neurotransmitter release; that is, it isn't just the wiring diagram that characterises a memory, but also the unique properties of each individual connection. But let's suppose, for the sake of argument, that each distinct mental state were encoded by the simplest possible mechanism: the on or off state of each individual neuron. This would allow 2^10^11 possible different mental states - more than enough for trillions of humans to live trillions of lifetimes and never repeat a thought. In theory, it should be possible to scan a brain in vivo using some near-future MRI analogue and determine the state of each of the 10^11 neurons, and store the information as a binary srtring on a hard disk. Once we had this data, what would we do with it? The details of ionic gradients, type, number and conformation of cellular proteins, anatomy and type of synaptic connections, etc. etc. etc., would be needed for each neuron, along with an accurate model of how they all worked and interacted, in order to calculate the next state, and the state after that, and so on. This would be difficult enough to do if each neuron were considered in isolation, but in fact, there may be hundreds of synaptic connections between neurons, and the activity of each connected neuron needs to be taken into account, along with the activity of each of the hundreds of neurons connected to each of *those* neurons, and so on. --Stathis Papaioannou _ Express yourself instantly with MSN Messenger! Download today - it's FREE! http://messenger.msn.click-url.com/go/onm00200471ave/direct/01/
RE: where do copies come from?
Stathis Papaioannou wrote: Recent theory based on the work of Eric Kandel is that long term memory is mediated by new protein synthesis in synapses, which modulates the responsiveness of the synapse to neurotransmitter release; that is, it isn't just the wiring diagram that characterises a memory, but also the unique properties of each individual connection. But these unique properties would be included in the simulation if you could record the levels of different neurotransmitters and proteins at each synapse, no? Wouldn't they still be present in the brain of a person that had recently died, at least if the individual neurons had not yet died at the moment the brain was frozen? In theory, it should be possible to scan a brain in vivo using some near-future MRI analogue and determine the state of each of the 10^11 neurons, and store the information as a binary srtring on a hard disk. Once we had this data, what would we do with it? The details of ionic gradients, type, number and conformation of cellular proteins, anatomy and type of synaptic connections, etc. etc. etc., would be needed for each neuron I don't think you'd need the details of ionic gradients at the moment of death, as long as you know how ionic gradients work in a generic neuron you'd probably just be able to restart them. along with an accurate model of how they all worked and interacted, in order to calculate the next state, and the state after that, and so on. This would be difficult enough to do if each neuron were considered in isolation, but in fact, there may be hundreds of synaptic connections between neurons, and the activity of each connected neuron needs to be taken into account, along with the activity of each of the hundreds of neurons connected to each of *those* neurons, and so on. Yes, but the hope is that neurons are not overly idiosyncratic in how they behave, that once you've learned to simulate a single neuron, then you could apply the same rules to other neurons as long as you knew their shape (branching of synapses, length of axon and so forth), the levels of various significant molecules at each synapse (and maybe elsewhere in the neuron), and maybe some other parameters I haven't thought of. And if you have a general algorithm that can simulate any neuron once you've measured the relevant parameters, then simulating an entire brain would mainly be a matter of being able to record these parameters in every neuron of a frozen brain, and of having a big enough computer (although you'd also have to know how to simulate the way that sensory neurons are stimulated by sense organs, how motor neurons affect simulated muscles, and how neurons interact with organs to affect things like hormone levels). Jesse
Re: where do copies come from?
Stathis Papaioannou wrote: Recent theory based on the work of Eric Kandel is that long term memory is mediated by new protein synthesis in synapses, which modulates the responsiveness of the synapse to neurotransmitter release; that is, it isn't just the "wiring diagram" that characterises a memory, but also the unique properties of each individual "connection". . This would be difficult enough to do if each neuron were considered in isolation, but in fact, there may be hundreds of synaptic connections between neurons, and the activity of each connected neuron needs to be taken into account, along with the activity of each of the hundreds of neurons connected to each of *those* neurons, and so on. Stathis also wrote: I believe the level of detail required and the complexity of the required models is grossly underestimated. Simply getting a 3D image of a brain down to electron microscopic detail, including all the synaptic connections, would be an enormous task, and it probabaly wouldn't tell us any more about the mind of the brain's owner than a picture of the books on a library shelf would tell us about the book contents. I would bet more on mediaeval monks decoding the data on a DVD sent back in time than I would bet on scientists decoding the contents of a human mind from cryopreserved brain sections. Let's cut through all this complexity and look at the functional equivalent of a neuron or a group of neuron. I want to distinguish between general architecture and particular architecture: general architecture will provide the framework within which any human brain could fit. Particular architecture is the architecture of a particular brain. 1) General Architecture The general architecture of the brain is a hot research project of the scale and importance of the Genome Project and is currently being worked on by major laboratories. We could speed up the functional identification of neuronal groups or modules by using general architecture apriori knowledge we have about these modules. For example the architecture of the visual cortex is well defined. We could treat it as a module with minor variations from individual to individuals due to genetic differences such as Single Nucleotide Polymorphism SNP. SNPs. Very soon we shall have the genetic map of all the human SNPs. We shall also have the general architecture of the brain and all its nominal variations. 2) Particular Architecture Imagine using an advanced version of a functional Magnetic Resonance Imaging (fMRI) device operating at the microscopic level on a slice of brain tissue. Without knowing exaclty what is in the brain tissue black box, it may be possible to identify their functional property and recreate these in silicon or any other convenient substrate. By the way, microscopic functional Magnetic Resonance Imaging is an existing technology that is currently being used. This is what I got using Google. Scholarly articles for functional magnetic resonance imaging microscop$ The primate neocortex in comparative perspective using ... - by Insel - 40 citations Neuroimaging and neuropathology in epilepsy: With ... - by Nishio - 1 citations Evaluation by Contrast-Enhanced MR Imaging of the ... - by Jeong - 2 citations 3) Combining General and Particular Architectures Fusing information to combine apriori knowledge of general architecture brain functions, and particular architecture data obtained from in situ functional measurements (e.g. fMRI), neurological and psychological measurements, as well as self-analysis, it may be possible to reconstruct a functional copy of the brain close enough as to be indinstinguishable from the original by the owner. How does the owner knows it is indistinguishable? This is a whole topic. He could for example do a series of partial substitutions to find out if it feels the same or not. For example, he could substitute in sequence the visual cortex, the auditory cortex, some of the motor functions We may be closer to this goal than you think. George
Re: where do copies come from?
Jesse Mazer wrote: [quoting Stathis, responding to a post by George Levy] The high standard I have described does not go nearly as far as copying the exact quantum state of every atom. It is merely aknowledging the fact that information in brains is not stored in the anatomical arrangement of neurons, any more than data on a computer is stored in the computer's circuit diagram. If you scan the anatomical arrangement of synapses *and* the concentration of all the relevant proteins at the synapses, you probably would have enough to run a simulation that would act like a continuation of the original person. The upload might find he'd lost his short-term memories of what happened immediately before he died and his brain was frozen (just as we often do when we regain consciousness after being suddenly knocked unconscious by an accident), but as I understand it long-term memories are stored in terms of the pattern of synaptic connections and the neurotransmitters at each synapse, and as long as the simulated neurons behave closely enough to how the original neurons behaved, shouldn't the upload behave like the original person in terms of personality, thought processes, emotions, preferences and so forth? I have no problem with the idea that everything about a person's personality, memories etc. is physically encoded in his brain, and that in principle, sufficiently detailed knowledge about his brain should allow an emulation on a computer which would be just like the original person. The problems are: (1) what is the level of detail of neuronal information required; (2) can this requisite information be preserved in a post-mortem specimen; (3) can the information be scanned or read in a way that can be used in a computer model; (4) can each subsystem of neuronal function relevant to cognition be modelled closely enough to allow emulation; (5) given adequate information and adequate models, is the computer power available up to the task of emulation in anything like real time? I believe the level of detail required and the complexity of the required models is grossly underestimated. Simply getting a 3D image of a brain down to electron microscopic detail, including all the synaptic connections, would be an enormous task, and it probabaly wouldn't tell us any more about the mind of the brain's owner than a picture of the books on a library shelf would tell us about the book contents. I would bet more on mediaeval monks decoding the data on a DVD sent back in time than I would bet on scientists decoding the contents of a human mind from cryopreserved brain sections. If mind uploads were to become a reality, I think the best strategy would be research into brain-computer interfacing. --Stathis Papaioannou _ Single? Start dating at Lavalife. Try our 7 day FREE trial! http://lavalife9.ninemsn.com.au/clickthru/clickthru.act?context=an99locale=en_AUa=19179
Re: where do copies come from?
On Thu, Jul 07, 2005 at 04:51:23PM +1000, Stathis Papaioannou wrote: I have no problem with the idea that everything about a person's personality, memories etc. is physically encoded in his brain, and that in principle, sufficiently detailed knowledge about his brain should allow an emulation on a computer which would be just like the original person. The Fair enough. You seem to suddenly deviate from this position at some point below, though. problems are: (1) what is the level of detail of neuronal information required; It doesn't matter, if that information is present in the vitrified brain. Preliminary results look good http://leitl.org/docs/cryo/ More results will be forthcoming in the next 1-2 years (this is something I know, not guess). (2) can this requisite information be preserved in a post-mortem specimen; See above. No showstoppers, under optimal conditions. (3) can the information be scanned or read in a way that can be used in a computer model; Yes, though TEM is probably not sufficient. Scaled up cryo AFM has more than enough resolution, and allows individual sampling of ablated molecules. In times where CO molecules are individually sorted by the isotopes by numerical control, and assembled into elaborate circuits, this shouldn't require much faith. (4) can each subsystem of neuronal function relevant to cognition be modelled closely enough to allow emulation; This is the most difficult point: you have to build a system which can abstract models, building at least 2-3 hierarchies, until you arrive at an isofunctional model well mapped to the hardware used. I have ideas in that direction, but nothing has been tested yet. (5) given adequate information and adequate models, is the computer power available up to the task of emulation in anything like real time? Near future will give us systems built from moles of bits (by self-assembly of individual molecular circuits). Pretty speedy systems, enough for a speedup of 10^6, if not more. The difficulty lies in obtaining a model which is isofunctional to the original. By the time you have that model, hardware will not be a bottleneck. I believe the level of detail required and the complexity of the required models is grossly underestimated. Simply getting a 3D image of a brain down No offense, but given the level of your ignorance, how do you know who has estimated what? to electron microscopic detail, including all the synaptic connections, would be an enormous task, and it probabaly wouldn't tell us any more about Yes. You need more resolution than TEM, btw. That's what automation is for. the mind of the brain's owner than a picture of the books on a library shelf would tell us about the book contents. I would bet more on mediaeval I told you we have results that there's probably enough preserved for the tissue to be retransplantable(!). Once it's in the dewar, time stops. I told you we have current methods allowing you to resolve submolecular structures in cryopreserved tissue. There's no fundamental reason why you can't image kg-sized vitrified objects at atomic resolution, at least transiently where it matters (what is this transmembrane protein, and how is it been modified, the membrane itself is rather boring). This is easily verified even with only online information. The information is preserved in the structure. Are you claiming that there is something missing? What, precisely, then? monks decoding the data on a DVD sent back in time than I would bet on scientists decoding the contents of a human mind from cryopreserved brain sections. You'll see individually accurate numerical models of simple critters + virtual models within the 20-30 year time frame. We could do this now with C. elegans, given 5-10 years, and a considerable budget. If mind uploads were to become a reality, I think the best strategy would be research into brain-computer interfacing. What is your estimated time frame for advent of technology like http://nanomedicine.com/ I, personally, am not holding my breath. YMMV. -- Eugen* Leitl a href=http://leitl.org;leitl/a __ ICBM: 48.07100, 11.36820http://www.leitl.org 8B29F6BE: 099D 78BA 2FD3 B014 B08A 7779 75B0 2443 8B29 F6BE signature.asc Description: Digital signature
Re: where do copies come from?
On Thu, Jul 07, 2005 at 12:49:07PM +1000, Stathis Papaioannou wrote: The high standard I have described does not go nearly as far as copying the exact quantum state of every atom. It is merely aknowledging the fact Two systems in the same quantum state being indistinguishable is only relevant for equilibrium constants and gedanken experiments. that information in brains is not stored in the anatomical arrangement of neurons, any more than data on a computer is stored in the computer's circuit diagram. If you copy a car down to the scale of a fraction of a millimetrel you can expect that the copy will work the same as the original, but if you copy a computer down to the sub-micron level you might end up with a machine that will run Windows XP or whatever, but you won't copy the data in RAM or on the hard drive. While it is not known exactly Okay, your objection is simply not enough resolution. I agree. TEM is not enough resolution by far. how information is stored in a brain, it is certainly dependent on such parameters as ionic gradients across cell membranes and the type, number, No, that's wrong. Gradients collapse (you see them collapsing on the EEG in realtime) after 20-30 sec of stopped blood flow, even at normothermic ischaemia (even without hypothermia and drugs (barbiturates, etc)). distribution and conformation of receptor and ion channel proteins. At its Yes, and quite a few other things. simplest, the brain could be seen as using a binary code, each neuron having two possible states, on or off. However, a snapshot of the state of each neuron will not allow a model of the brain to be built, because all the anciliary cellular machinery as above is needed to work out how to get from one state to the next. If it were otherwise, why would all this complexity have evolved? I do not understand your objections here. -- Eugen* Leitl a href=http://leitl.org;leitl/a __ ICBM: 48.07100, 11.36820http://www.leitl.org 8B29F6BE: 099D 78BA 2FD3 B014 B08A 7779 75B0 2443 8B29 F6BE signature.asc Description: Digital signature
Re: where do copies come from?
Le 07-juil.-05, à 04:55, Stathis Papaioannou a écrit : How does a quasi-zombie differ from a full zombie? Well a full zombie is not conscious at all. By a quasi-zombie I was meaning someone with some consciousness pathologies. And how could his descendants ever realise this, even after centuries - wouldn't this require a foolproof 3rd person method of determining 1st person experience? After centuries of immortality people can have better theories on correlations between some experience and some third person features of their brain. I have myself once believed that synesthesia (hearing color, seeing sound) was sort of poetical stuff until I read people have discovered specific neuronal channels corresponding to it. But here with immortal zombie I was just alluding on the fact that we can't known for sure the level of substitution. We must bet on theories, and in practice we let the doctor make the bet. Logician use model for testing the validity of an argument, and I can *conceive* (not believe!) something like 1- Hameroff is right and consciousness is produced by information processing in the microtubule in interaction with gravitation (say, this does not contradict comp) 2- Without it, the neurons can manage very high level information processing so that without the microtubule working someone can still pass a (long) Turing test 3- Yet, they could not pass a much longer Turing test. So that ultimately people discovered they are in a sort of loop, etc. OK, this could contradict Darwin, and I could search a better example, but my point was just that nobody can give garantees on that matter (actually it is the same with taking a plane, or just a cup of tea). Bruno http://iridia.ulb.ac.be/~marchal/
Re: where do copies come from?
Le 07-juil.-05, à 08:51, Stathis Papaioannou a écrit : If mind uploads were to become a reality, I think the best strategy would be research into brain-computer interfacing. I think so. I have recently discovered impressioning progress in neuronal nets used for handicaped (completely paralyzed) people. They are able to learn fast the handling of a cursor and files on a computer. No doubt it will be used soonely to vide-games and in the middle run it could replace the keyboard for most application. Then those neuronal nets will grow into artificial sort of neocortex and I can imagine taking up the main role in our brain information processing. Then we could just abandon brain! Yet I think Cryo will progress too, most probably by genetic manipulation, copying and ameliorating some molecular technics used by frogs I think. Bruno http://iridia.ulb.ac.be/~marchal/
Re: where do copies come from?
Le 07-juil.-05, à 16:27, Eugen Leitl a écrit : Currently, there's only output, not input. It's invasive, and the electrodes don't age well. Actually (but I'm not a specialist) I read about systems not using electrodes. The neural nets was sensible to the waves of barin activity like in a Electro Encephalo Gram (EEG in french, sorry). Thanks for the info and links. Bruno http://iridia.ulb.ac.be/~marchal/
Re: where do copies come from?
On Wed, Jul 06, 2005 at 10:31:50PM +1000, Stathis Papaioannou wrote: This may be getting a little off topic for this list, but it has always seemed to me hopelessly naive to think that a person's mind could be Perhaps, perhaps not. emulated from cryopreserved brain tissue. It would be like trying to recreate a telephone conversation by examining a diagram of a city's telephone network. Even if you could get the anatomy correct, which would This is not a correct analogy. Individual spike trains are readily regenerated from a neuron circuit. Neurons are not people on the telephone. There's nobody using your telephone network above but whatever intrinsic activity there is in the network itself. mean knowing every neuron's connection with every other neuron, you would Of course. Empirically, submolecular resolution is available (cryo AFM). Whether it is going to be needed (say, to read the degree of phosphorylation of a protein, or identify individual ion channel type) is another question. The information is there, and we can almost access it with current technology (completely ignoring scaling up issues). have nowhere near enough information to model a human brain, let alone a particular human brain state at the time of death. You would also need to Which information you think would be missing? know the electrical potential at every point of every cell membrane; the ionic gradients (Na, K, Ca, pH and others) across every cell membrane, including intracellular membranes; the type, position and conformation of every receptor, ion channel and other proteins; the intracellular and local extracellular concentrations of every neurotransmitter; the workings of the cellular transport, synthetic and repair mechanisms for each neuron and probably also for each supporting glial cell; the intracellular and extracellular concentration of other small molecules such as glucose, O2, CO2; how all of this is changing with respect to time; and probably thousands of other paramemters, many of which would currently be unknown. We empirically know that individual animal or human pattern can resume from zero electrochemical activity and about zero metabolic activity (few degrees above 0 C). We also have evidence (not fully validated yet) that vitrified retransplanted (renal, so far) tissue is viable. Taken together it strongly hints that there is enough information, and that most of above factors cited are empirically incorrect. You don't need them. There might be showstoppers yet, but current trends are good. Some publications are in the pipeline, hang on for a year or two. Most of this information would probably be lost post-mortem, but even if some process could be found that preserves it, the sort of technology needed to scan a brain at this sort of detail would probably not be far short of atom for atom matter duplication and teleportation. You cannot scan a living cephalon without invading it with several liters of active nanomachinery. Most likely, no such machinery will be available within our lifetime. Because of this I'm focusing on cryopreserved people. -- Eugen* Leitl a href=http://leitl.org;leitl/a __ ICBM: 48.07100, 11.36820http://www.leitl.org 8B29F6BE: 099D 78BA 2FD3 B014 B08A 7779 75B0 2443 8B29 F6BE signature.asc Description: Digital signature
Re: where do copies come from?
Stathis Papaioannou wrote: You would also need to know the electrical potential at every point of every cell membrane; the ionic gradients (Na, K, Ca, pH and others) across every cell membrane, including intracellular membranes; the type, position and conformation of every receptor, ion channel and other proteins; the intracellular and local extracellular concentrations of every neurotransmitter; the workings of the cellular transport, synthetic and repair mechanisms for each neuron and probably also for each supporting glial cell; the intracellular and extracellular concentration of other small molecules such as glucose, O2, CO2; how all of this is changing with respect to time; and probably thousands of other paramemters, many of which would currently be unknown. This is unfair. According to this strict standard you are not the same person today as you were yersterday. In fact even an automotive transportation method would violate the above standard. We can't expect a Star-Trek tranporter to have more High Fidelity than a car. The question is how much can we relax the standard until the person at the output is not the same as the person at the input. In a brain substitution experiment, when should the patient say yes doctor or no doctor? George
Re: where do copies come from?
How does a quasi-zombie differ from a full zombie? And how could his descendants ever realise this, even after centuries - wouldn't this require a foolproof 3rd person method of determining 1st person experience? --Stathis Le 06-juil.-05, à 22:12, George Levy a écrit : In a brain substitution experiment, when should the patient say yes doctor or no doctor? The comp answers: this is a question bearing on a private and personal domain, including the possible relations you have with a doctor you thrust (if that exists!). The level is a matter of personal opinion or choice, the lower the better probably ... No guarantees of success at all. Logically, it could be that the ``pioneer of immortality will just be quasi-zombie, although their descendant will take centuries to realize that! I don't say it will be necessarily so. There are other scenarios ... Bruno http://iridia.ulb.ac.be/~marchal/ _ SEEK: Over 80,000 jobs across all industries at Australia's #1 job site. http://ninemsn.seek.com.au?hotmail
Re: where do copies come from?
George Levy wrote: [quoting Stathis] You would also need to know the electrical potential at every point of every cell membrane; the ionic gradients (Na, K, Ca, pH and others) across every cell membrane, including intracellular membranes; the type, position and conformation of every receptor, ion channel and other proteins; the intracellular and local extracellular concentrations of every neurotransmitter; the workings of the cellular transport, synthetic and repair mechanisms for each neuron and probably also for each supporting glial cell; the intracellular and extracellular concentration of other small molecules such as glucose, O2, CO2; how all of this is changing with respect to time; and probably thousands of other paramemters, many of which would currently be unknown. This is unfair. According to this strict standard you are not the same person today as you were yersterday. In fact even an automotive transportation method would violate the above standard. We can't expect a Star-Trek tranporter to have more High Fidelity than a car. The question is how much can we relax the standard until the person at the output is not the same as the person at the input. In a brain substitution experiment, when should the patient say yes doctor or no doctor? The high standard I have described does not go nearly as far as copying the exact quantum state of every atom. It is merely aknowledging the fact that information in brains is not stored in the anatomical arrangement of neurons, any more than data on a computer is stored in the computer's circuit diagram. If you copy a car down to the scale of a fraction of a millimetrel you can expect that the copy will work the same as the original, but if you copy a computer down to the sub-micron level you might end up with a machine that will run Windows XP or whatever, but you won't copy the data in RAM or on the hard drive. While it is not known exactly how information is stored in a brain, it is certainly dependent on such parameters as ionic gradients across cell membranes and the type, number, distribution and conformation of receptor and ion channel proteins. At its simplest, the brain could be seen as using a binary code, each neuron having two possible states, on or off. However, a snapshot of the state of each neuron will not allow a model of the brain to be built, because all the anciliary cellular machinery as above is needed to work out how to get from one state to the next. If it were otherwise, why would all this complexity have evolved? --Stathis Ppapaioannou _ Sell your car for $9 on carpoint.com.au http://www.carpoint.com.au/sellyourcar
Re: where do copies come from?
Stathis Papaioannou wrote: George Levy wrote: [quoting Stathis] You would also need to know the electrical potential at every point of every cell membrane; the ionic gradients (Na, K, Ca, pH and others) across every cell membrane, including intracellular membranes; the type, position and conformation of every receptor, ion channel and other proteins; the intracellular and local extracellular concentrations of every neurotransmitter; the workings of the cellular transport, synthetic and repair mechanisms for each neuron and probably also for each supporting glial cell; the intracellular and extracellular concentration of other small molecules such as glucose, O2, CO2; how all of this is changing with respect to time; and probably thousands of other paramemters, many of which would currently be unknown. This is unfair. According to this strict standard you are not the same person today as you were yersterday. In fact even an automotive transportation method would violate the above standard. We can't expect a Star-Trek tranporter to have more High Fidelity than a car. The question is how much can we relax the standard until the person at the output is not the same as the person at the input. In a brain substitution experiment, when should the patient say yes doctor or no doctor? The high standard I have described does not go nearly as far as copying the exact quantum state of every atom. It is merely aknowledging the fact that information in brains is not stored in the anatomical arrangement of neurons, any more than data on a computer is stored in the computer's circuit diagram. If you scan the anatomical arrangement of synapses *and* the concentration of all the relevant proteins at the synapses, you probably would have enough to run a simulation that would act like a continuation of the original person. The upload might find he'd lost his short-term memories of what happened immediately before he died and his brain was frozen (just as we often do when we regain consciousness after being suddenly knocked unconscious by an accident), but as I understand it long-term memories are stored in terms of the pattern of synaptic connections and the neurotransmitters at each synapse, and as long as the simulated neurons behave closely enough to how the original neurons behaved, shouldn't the upload behave like the original person in terms of personality, thought processes, emotions, preferences and so forth? Jesse
where do copies come from?
My initial purpose in discussing copies on this list was as an analogy for the copies of an observer in other branches of the multiverse, to make a point about the significance of absolute versus relative measure in the QTI. However, the discussion has obviously taken off in a different direction, and it appears that now we are not talking about thought experiments, but about something that might become a reality at some future point in human evolution. But while we have been discussing the rich philosophical issues raised by this possibility, and touched on some of the social issues in a world where copying is common, nobody has really talked about how these copies will actually be made. It seems to me that our old workhorse, the Star Trek teleporter, even if theoretically possible, would be a fantastically difficult thing to make. Any civilization advanced enough to be up to the task of building one would have long ago developed much easier methods of copying and transferring minds by going all electronic (or photonic, or whatever), so that atom for atom duplication of a biological entity would be a pointless exercise. It therefore seems likely that if copying minds is to be commonplace and easy, the minds will be uploaded humans or AI's on a computer network. This would change *everything* that has so far been said about copies and their relationship to each other and to the original. When I think about whether concern for the welfare of one of my copies is selfishness or altruism, I do so from the point of view of a poor unmodified human who experiences a single track, unidirectional stream of consciousness unfolding linearly in time and relying on memory to hold it all together. But if I were a computer program with ability to rewrite my own source code (or have someone else do it), that all goes out the window. I would be able to merge with other people, spin off sub-personalities, enhance any attribute or ability I liked, just *decide* what philosophical or other belief I wanted to hold, make myself altruistic on Mondays and selfish on Tuesdays, edit my memory so that things happen in a different order, assimilate any experience that I fancy, be basically content with life but with a cynical edge and a mild yearning for old-style human limitations, and so on and on... --Stathis Papaioannou _ Dating? Try Lavalife get 7 days FREE! Sign up NOW. http://www.lavalife.com/clickthru/clickthru.act?id=ninemsncontext=an99a=20233locale=en_AU_t=33473
