X-Message-Number: 3590 From: (Thomas Donaldson) Subject: SCI.CRYONICS Re: Flash Freezing & Uploading Yourself Date: Tue, 3 Jan 1995 22:11:27 -0800 (PST) Hi again to everyone: 1. About Coetzee and Bozzonetti: I took Bozzonetti's last "ghosts" posting to be humorous. He may not understand conventions such as :). As for the Peltier effect, we might step back a bit from what Coetzee is saying ask the question he is trying to answer: is there a fast way to cool someone down? Here is a SPECULATION: let's suppose we could find some nano- device which would convert, alone or with other devices of its kind, the heat in a patient's body into (say) x-rays (which will pass through the body and dissipate that heat elsewhere). Heat goes with infrared, ie. low frequency light waves. To detect that heat the nanodevices would (I think) need to have a lower temperature than the body they are attempting to cool. And for those who worry about spectral lengths, I did point out that more than one such device may be involved. I don't really claim that this will work. The game I am playing here is: don't bash people for errors. Try to use their (admittedly wrong) suggestions to come up with something better: closer to working, more physically plausible, etc. There is, of course, the separate question of whether or not rapid cooling would help in the first place. A fair question. Perhaps if we collectively started to come close to a workable scheme, it would also start to be reasonable to ask that question. Perhaps its reasonable right now --- but it IS a separate question. 2. To Mr. Clark: I would feel much happier with your discussion both of what I said and of the issue of uploading if you were to learn more about how brains work in the first place. I did, after all, suggest a book to start with, and if you wish I'll write out a larger bibliography. Particularly as a mathematician, one major problem about your idea is that one counterexample will shoot it down. I personally met Littlewood when he was (I think) over 80 and I was in grad school. He was still writing significant papers, and ended his talk (at the U of Chicago) with a request to use the local computer. This is the Littlewood of Hardy and Littlewood, famous for the book INEQUALITIES (which I believe is still read and published, and republished (1st edition 1934). Moreover, a great deal more goes into doing significant mathematics than simple memory. ENERGY is important, the kind of energy that younger people have in which they will stay up 3 days working on a problem. And finally, of course, the milieu in which a mathematician works often changes as he/she gets older. They are asked to sit on committees, referee papers, deal with grad students, attend dinners, etc etc etc. Given enough of that, it's hardly surprising that they don't produce work as good as that they did when they were younger! Yes, our memory may be significantly less than is thought (by whom?). But when we learn something new we don't have to create lots and lots of new synapses because the old ones are now "full". We may create more synapses, true, but not as many as we'd need if LTP were a permanent store of memory --- which it isn't likely to be (an important way to learn more about memory and an important stage in memory, yes, but not the whole of it). Remember that (from experiments on perception, problem solving, and other things using MRI) very many neurons are activated in learning. As for the problems of uploading, creating a device or a system which REALLY acts like a set of neurons (and supporting glial cells) looks a great deal harder now that we know much more. Neurons don't just pass impulses through electrical currents. They also use chemicals. Some may be released very precisely at just one synapse, others (such as the neurotransmitters NO and CO which are gases) will affect nearby cells. Some synapses seem specialized for only one mode of transmission, others are not. We don't even yet have a complete list of the neurotransmitters involved. Then, to add to the problem, a significant chance exists (from studies with neural nuclei accessible to experiment: see Purves, BODY AND BRAIN) that as a result of our experience our nervous system remodels itself, even in adulthood. In an electrical device this would be as if it somehow created new connections between its parts, and sometimes destroyed the old ones --- not as replacements grow, but as separate uncorrelated events. (It is certainly true that this remodelling happens in late embryonic stages and early infancy). So what does this say about imitating a brain with nanotechnological devices? They'd have to be rather complex devices, at a minimum: complex enough that the creature resulting might look very much as we do now, even if the materials of which it is made happen to differ. If you really want to do this, it might make more sense to try setting a brain up as software in a highly parallel computer. That would get around a PART of the "remodelling connections" problem, though probably not all of it: after all, you would be modelling a brain on something with fixed connections. To deal with things like the diffusion of NO or CO, too, you might find that even running on many processors your brain slows down a good deal compared to the speed of a single element. (Biological devices CAN operate at high speed: modifications of the pigments we use to see are right now being considered as a basis for high speed computer memories. It's an interesting problem why we are "slow". Part of it may be that we aren't, its just that there is a lot to do. But that is an entirely separate question which I won't discuss here). Best and long long life, Thomas Donaldson (PhD Math) presently involved with parallel computer software. Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=3590