Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!mips!wdl1.wdl.loral.com!wdl1!mikeb From: mikeb@wdl31.wdl.loral.com (Michael H Bender) Newsgroups: comp.ai.philosophy Subject: Re: Minds, machines, and Godel Message-ID: Date: 17 Jan 91 20:39:43 GMT References: <1991Jan16.035058.7465@bronze.ucs.indiana.edu> Sender: root@wdl1.wdl.loral.com (SUPER USER) Organization: Ford Aerospace, Western Development Laboratories Lines: 29 In-Reply-To: chalmers@bronze.ucs.indiana.edu's message of 16 Jan 91 03:50:58 GMT Nntp-Posting-Host: wdl31 David Chalmers quotes: if I were a particular Turing Machine T, there would be a mathematical sentence G (the "Godel sentence" of T) that I could not prove. But in fact I can see that G must be true. Therefore I cannot be T. This holds for all T, therefore I am not a Turing machine. I am not an expert in these areas, but I do have a question: isn't the word "prove" being used in two different ways? I.e., when you say: "there would be a mathematical sentence G (the "Godel sentence" of T) that I could not prove" ^^^^^ you are referring to proof in the mathematical/formal context. However, when you say: "But in fact I can see that G must be true. Therefore I cannot be T" ^^^^^^^^^^^^ you are referring to a completely different concept -- what we believe or we "know" about the world. Am I missing something? Because clearly there is a well understood difference between these two. Clearly people often believe things which are not provable and in fact, psychological studies have shown that people will, on occasion, refuse to believe things which they know are provable. Mike Bender