X-Message-Number: 9153 From: Thomas Donaldson <> Subject: Re: CryoNet #9142 - #9148 Date: Wed, 11 Feb 1998 21:12:48 -0800 (PST) Hi everyone! To Mr. Strout: (Well, I really thought you were a PhD, but it doesn't matter). Your answer raises further questions. If this reconstructed machine into which your memories have somehow been implanted is at the same scale as you are, then I do not understand just why you believe we can work so finely (nano- finely, so to speak) with this machine but somehow cannot do the same with biological objects such as brains. One initial thought was the idea that perhaps you felt that we understood matter at that scale, for electronics purposes, well enough or close to well enough already, but did not understand how brains worked at that scale. However there is a problem there: we can hardly make an electronic machine containing your memories unless we know how to read off the memories inside brains --- and for cryonics purposes, damaged brains, too. It should be clear that no essential barrier prevents us from working with biological material using tools which are not biological. Any biolab in any university will show that. We do have to understand what we're doing, when we work with these things, and at the lower levels we have now a better understanding of computer memories than of brain memories --- but that is irrelevant to the problem, which requires that we understand brain memories to remake you in any form at all. Or is YOU to be merely something which looks like you and superficially behaves like you? I don't believe you meant it so simply. There is, just to add a bit of likelihood to this picture, a growing sense that long term memory formation occurs by the creation of new synapses and new connections. Cf the recent article in SCIENCE, ER Kandel et al (270(1998) 338-341) for a discussion of this in Aplysia in a different context. With references. This suggests to me that the current electronic neural nets won't match brains in their behavior (NOTE that I say nothing here about speed). If we create a device capable of imitating your brain on the scale at which your memories are stored, then that device will have to have some ability to grow and change, and not in any fixed mode (ie. turn on connections already there, for instance). So why is it that you believe we can make electronic (or light, or other) networks of connections to match that of our brain, but cannot do so with biological tissue? I know we can't do this now, but the question is that of what is possible IN PRINCIPLE. And I will add that we at present don't know enough to make even a small "brain" of anything at all --- electronic or not. Of course one major feature of biological tissue is that it is floppy, and wet, and moves around all the time (when it's alive). But then I find it hard to imagine remaking YOU (or me) into something which does not have such features. And the insights in Aplysia memory suggest that such behavior is essential to us, not just a side effect of the way we are made. It does have its advantages, as you know --- even on a simple level. If I get dings and scratches they heal over, while if your car, television, or computer gets dings and scratches they stay there forever. And please be careful: I am not claiming here that creatures able to carry out such self repair must necessarily be composed of the same materials and systems as we are. But it IS an advantage, especially if we want to survive a long time. So over to you on this issue. Best wishes and long long life, Thomas Donaldson Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=9153