Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!agate!helios.ee.lbl.gov!nosc!humu!uhccux!lee From: lee@uhccux.uhcc.hawaii.edu (Greg Lee) Newsgroups: comp.ai Subject: Re: A Definition of "Symbol," "Symbolic," and "Symbol-Manipulation" Message-ID: <3484@uhccux.uhcc.hawaii.edu> Date: 15 Mar 89 12:39:21 GMT References: Organization: University of Hawaii Lines: 36 From article , by harnad@elbereth.rutgers.edu (Stevan Harnad): # ... # the basis of EXPLICIT RULES that are (3) likewise physical tokens and # ... i.e., it is purely SYNTACTIC, and consists of (5) rulefully COMBINING # and recombining symbol-tokens. There are (6) primitive ATOMIC ... This characterization of 'symbol' is not appropriate for either the ordinary use of the word or the way it is used in logic. In the case of the latter, a logical semantics (e.g. the truth table characterization of sentence logic) cannot have symbols, by this account. But that's ok -- we can take the proposed definition as giving a special technical usage for purposes of discussion, though we'll have to remember that if later the conclusion is drawn that human thought is non-symbolic because it is based at least in part on denotations, this follows trivially from the artificial usage introduced earlier. Mustn't allow proof by definition. Does this definition help clarify whether brain-events evoked by or associated with perception, or evoked in other ways, can properly be called symbols? I don't see that it does. Of course if speculation is not to be permitted, we could point out that no one has given explicit rules which completely characterize the way these brain-events interact, based their physical form. Then the controversy is settled: human thought is not symbolic. No explicit syntactic rules. But this whole discussion is speculative. If we can imagine that the entire verbal behavioral repertoire of a human Chinese speaker has been captured in rules, it's either a small further step or no further step to imagine the syntax of brain-events has been discovered, also. In for a pound, in for a penny. Greg, lee@uhccux.uhcc.hawaii.edu