X-Message-Number: 20976 Date: Sun, 26 Jan 2003 09:41:05 -0500 From: Thomas Donaldson <> Subject: CryoNet #20963 - #20971 Several people have objected to what I said about MOLECULAR nanotechnology. I have read their objections. The fundamental problem is not that of putting someone together again when you know where all his/her molecules should go. The problem is that of FINDING OUT WHERE THEY SHOULD GO. It is very important here that is virtually no need to repair the molecules themselves; the damage caused by freezing is on a much larger scale, as I have said. I don't even doubt that nanodevices could enter a frozen body and work out the location of all of its molecules. The problem is that those locations will be WRONG. Not only that, but all our clues to what those locations should be will exist on a larger than nano scale. They could not be readable by a single nanodevice. Nor am I arguing that repair is impossible. We could have devices which gather together input from many of the nanodevices examining the damaged brain. That would of course require communication between them, and in that sense they would cease to be INDEPENDENT devices, any more than our white blood cells are independent. That is what I mean when I say that you would no longer be using a nanodevice, but instead a repair reassembler made up of many of them. Some more specific comments: For Kennita Watson: the problem involves not just fitting together simple pieces of a jigsaw puzzle but also working out just what the pieces are. They will not have been broken so that their boundaries will be clear, nor will they even retain their original shape. For James Swaze: in a sense it does not matter how small you can make the computer itself. There remains the problem of getting information to it and the calculation problem which it must perform. Remember that I was specifically arguing against MOLECULAR nanotechnology, not nanotechnology itself. The nanodevices engaged in repair will have to share information and cooperate constantly, precisely because they are working with a problem which is physically much larger than they are and larger than any individual one can perceive. Their inputs must go into a separate computer (or hierarchical set of them) to be worked on and the CORRECT locations inferred for repair. And as I said before, even if the computer itself were nanosized, the total set of devices working on repair would be no more a nanodevice than our hands are nanodevices. Each nanopart would do only part of the task. I will deal with your other problems with my comments on repair in a separate message. For Brian Stewart: at least you worked out that I wasn't arguing against nanotechnology! Yes, a device of the kind you describe would be able to repair brains. Clearly lots of details would need to be worked out, but I'd say that was the direction in which to go. Best wishes and long long life to all, Thomas Donaldson Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=20976