Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!bcm!dimacs.rutgers.edu!aramis.rutgers.edu!athos.rutgers.edu!nanotech From: bill@braille.uwo.ca (W.B. Carss) Newsgroups: sci.nanotech Subject: Re: Is this stuff for real? Keywords: reality nanotech questions Message-ID: Date: 8 Mar 91 21:32:41 GMT Sender: nanotech@athos.rutgers.edu Organization: The Computer Braille Facility, UWO, London Lines: 77 Approved: nanotech@aramis.rutgers.edu In article bill@braille.uwo.ca (W.B. Carss) writes: >[The arguments in this message are, fortunately for the future of life > on Earth, flawed. See below. -j] >[The major flaw in the above argument is that it doesn't take any account > of the difference between a machine and an animal. Bill has taken a > major (and completely unsupportable) leap of faith: since we are > quite likely to make mistakes (true) our machines will suddenly become > supermachines able to take over the world in spite of all we can do to > resist them. No, I don't believe I have taken that leap at all. The point that you have apparently missed or refuse to acknowledge is a little aspect of industry called "quality control". If you machine building is so un-flawed, why do we need quality control? If our production methods were so perfect you wouldn't ever see people returning things that don't work properly. Computers (at least ours) make errors perhaps once every few million operations. Why is that? What is the result of the error? In the case of nanobots, it would take billions of them to create anything of an appreciable size i.e. something that is large enough for us to get any real use out of it. If you have billions of machines each making one mistake every ten million operations, that makes a lot of mistakes. Certainly, in self-replicating nanobots most of the mistakes would result in nanobots that are not viable. But in those cases where the mistake has not led to what we will call a fatal error what will be the result? We don't know. Let's say we have built machines that respond to the colour navy blue. We have designed these machines to replicate themselves and in the process an error occurrs so that some of the machines now respond to robin's eff blue not navy blue. the machine would still "work", it would just be responding to a different shade of blue. Whether this is a serious aboaration or not depends on what the machines "do" when they come into contact with the activating colour. Wuppose they are designed to break-down the navy blue item whatever it is. Those machines that are now responding to robin's egg blue would be breaking-down robin's egg blue items not navy blue items. What would be the result of all of that? As far as killer nanobots are concerned, certainly that may be the stuff of which science fiction is made. My point still is (and was) a question. How do we control what would essentially be mechanical errors? -- Bill Carss bill@braille.uwo.ca [Again: You are talking about two distinct phenomena: (a) [shades of blue] a machine with a specific, designed, function, performs that function on something slightly different than intended; (b) [gray goo] due to an error in copying, a plan for a ten-thousand part machine which does one specific function and runs on one specific fuel, becomes a plan for a 100 million part machine, able to perform hundreds of functions, recognize the circumstances under which each should be performed, run on a wide variety of naturally occuring energy sources, and survive the chemical attacks of the natural, highly adaptable microorganisms it will compete with. Think of a car again for a moment. Suppose we have a working car, and we come up with some improvement that consists of a new design for one of the mechanical parts of the engine. Can you design a car so that to incorporate the new part, I simply open the hood and throw it in? Well, guess what: cells work that way. If a copying mistake produces a better part, anywhere, it works, automatically. In a mechanical design, you have to change the whole design in a highly coordinated way to incorporate improvements. Almost all the copying errors in a cell are detrimental, i.e. they make it work less well. A tiny fraction improve, or simply change, its function. Almost all of even that tiny fraction, in a mechanical design, would simply cause it not to work at all. Try changing a bubblesort program into a heapsort, one character at a time, with the constraint that each intermediate form not only sorts correctly but does so at least as well as bubblesort. --JoSH]