Path: utzoo!attcan!uunet!lll-winken!csd4.milw.wisc.edu!mailrus!cornell!uw-beaver!ssc-vax!bcsaic!ray From: ray@bcsaic.UUCP (Ray Allis) Newsgroups: comp.ai Subject: Re: Chinese Room Keywords: symbols Message-ID: <10884@bcsaic.UUCP> Date: 21 Mar 89 23:37:32 GMT Organization: Boeing Computer Services-Commercial Airplane Support Lines: 120 (Sorry this reply took so long, but our USENET feed disappeared for about a week.) > From: mike@arizona.edu (Mike Coffin) > Message-ID: <9690@megaron.arizona.edu> > Organization: U of Arizona CS Dept, Tucson > > From article <10704@bcsaic.UUCP>, by ray@bcsaic.UUCP (Ray Allis): > > Is there some evidence > > that would cause you to re-inspect your conviction that the "Systems Reply" > > is sufficient? What part of the process by which I came to see the > > inadequacy of the symbol processing approach can I explain more clearly? I asked the question hoping to get something that would help me improve my own arguments. Thanks for the clear statement of your position. > Sure. Convince me that no symbol-pushing engine can simulate pieces > of my brain, if you make the pieces small enough. My belief in the > systems reply is based exactly on this: > > 1) I have in my possesion a system that seems to understand and think: > my brain. (My wife might argue about that...) O.k., I'm willing to give you the benefit of the doubt. :-) > 2) The brain (and the rest of the body) is made up of physical parts: > electrons, atoms, molecules, cells, organs, etc. Agreed. No one but a theoretical physicist would quibble. :-) > 3) I see no reason, in principle, that such parts can't be simulated > to any desired precision, given powerful enough computers. Not > necessarily Turing machines; we may need random bits. I don't either, except there may be *some* limit on precision. > 4) Given such simulators, I see no reason, in principle, that I can't > begin replacing my biological parts with simulated parts. The problem here is a shift in the meaning of the word "simulation" between statement 3) and statement 4). (NOTE: I'm talking about DIGITAL COMPUTER simulations here. Wall panelling of "simulated" walnut is still a real material, though one might more precisely call it a poor duplicate. And a "mental model" is (arguably) non-physical, though maybe it should be called a mental simulation. A distinction must be made whether we are discussing a physical thing or a symbol system.) I have no doubt we might be able to *duplicate* part or all of the brain, and thereby (we believe) the mind, but "simulate" is not "duplicate". + You can *simulate* something: a *symbolic* process. + You can *model* something: i.e. produce an abstracted form. This can be either physical or symbolic. (Models are characteristically "reduced", i.e. smaller and less complex than the thing modelled. They do not have all the properties of the original.) + You can *duplicate* something: a *physical* process. At issue here is the distinction between simulation and implementation or duplication. You want to actually IMPLEMENT parts of your brain, but in different media. One case is a physical *duplication* of parts of your brain, but substituting silicon or supercooled whatever for the biological components, the other case is not physical but symbolic; that is, constructed from the *relationships among the members of a set of symbols*. Such a simulation is disconnected from the physical universe. Not incidentaly, your argument illustrates the very problem I'm trying to point out: the *logic* is valid, but the argument's relevance to reality is determined by the MEANING of the statements. This is exactly the problem with symbol systems. Denotation and connotation (meaning) do not enter into the manipulation of symbol systems. (BTW, that's also their great advantage, I don't want to give the impression I think symbolic reasoning should be discarded!) > Obviously I will need some chemical peripherals to interface the > two systems. There's a big difference between a model airplane and a simulated airplane, or a simulated leg and a prosthetic. A simulated air crash won't kill anyone or break a plane. That's why pilots are trained in simulators. A simulated leg does an amputee little direct good, it's for the doctor's benefit to analyze the situation. The patient needs a *duplicate*, even a poor one. Simulated bells don't ring. In fact, you *can't* replace your real brain with a simulation. That's why we have to build supercolliders. Simulation doesn't provide all the information we need. In fact digital computer simulation, like deductive logic (which it is) doesn't provide anything which was not "built in" to it by design. If you try to pour 11 oz. of wine into a 10 oz. glass, physical reality constrains the result. Not so with a simulation. The DESIGN of the (symbolic) simulation constrains it. THERE IS NO, repeat NO, "real" relationship between a symbol and its denotation; the relationship exists only in a mind. The simulation (all simulations) are unaffected by the real world! A simulated wing is not affected by sunlight unless we specify such affect in the design of the simulation. There is *NO* possibility of affect from surprise factors. So, if we didn't think of everything, the simulation will not mimic reality. (It fails in proportion to our ignorance!) You'll agree we can't build an atom from symbols; symbols are not real things. What's important about a symbol is its *meaning*, denotation and connotation. Some symbols denote other symbols; the marks you're reading now denote sounds which denote ideas. But, at bottom, symbols are associated with non-symbols. The non-symbols are what we compare to detect similarity and difference, to discover analogy... to think. > 5) Given that the simulations are accurate enough, I see no reason that > at some point in the process of replacement I will cease to > understand: e.g., that with 23.999% of my brain simulated, I understand, > but with 24.000% I cease understanding. > -- > Mike Coffin mike@arizona.edu > Univ. of Ariz. Dept. of Comp. Sci. {allegra,cmcl2}!arizona!mike > Tucson, AZ 85721 (602)621-2858 Ray Allis ray@atc.boeing.com or bcsaic!ray