Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site watdcsu.UUCP Path: utzoo!watmath!watnot!watdcsu!dmcanzi From: dmcanzi@watdcsu.UUCP (David Canzi) Newsgroups: net.philosophy Subject: Re: Sc--nce Attack (self-awareness) Message-ID: <1749@watdcsu.UUCP> Date: Sat, 12-Oct-85 00:56:25 EDT Article-I.D.: watdcsu.1749 Posted: Sat Oct 12 00:56:25 1985 Date-Received: Sat, 12-Oct-85 18:32:40 EDT References: <45200016@hpfcms.UUCP> <1605@pyuxd.UUCP> Reply-To: dmcanzi@watdcsu.UUCP (David Canzi) Organization: U of Waterloo, Ontario Lines: 58 Summary: In article <2298@sjuvax.UUCP> tmoody@sjuvax.UUCP (T. Moody) writes: >>> John Searle, who argues that human cognition (in particular >>> intentionality and meaning) is caused by the powerful biochemical >>> machinery of our brains, is the author of wonderfully cynical plain >>> language attacks against the assertions by big name AI folks that >>> human cognitive states are digitally simulatable. [Ellis] >>> >>> As long as it only simulates the >>> formal structure of the sequence of neural firings at synapses, it >>> won't have simulated what matters about the brain, namely its causal >>> properties, its ability to produce intentional states. [Searle, quoted > by Ellis] "formal structure... causal properties... intentional states..." Plain language? > Searle is arguing that the "causal properties" of the brain >are not obtained by merely simulating the FORMAL STRUCTURE of the neural >activity. By "formal structure", Searle means something quite precise. >The formal structure of the brain is the Turing machine algorithm that >it is instantiating. This formal structure is what functionalists claim >is the essence of mind; to be in a mental state is to instantiate a >Turing program-type.... Searle argues against... functionalism... > >The whole point of functionalism is that mental states are substrate- >independent; that they can be simulated -- AND HENCE INSTANTIATED -- >without respect to the physical ingredients of the system. All I know about John Searle and functionalism is what I gather about them from the above quotes. I don't know what Searle means by "causal properties" and "intentional states". But I'm not one to let ignorance prevent me from speaking. Human brains don't exist in isolation -- they come with a body attached. The environment affects the sensory organs, causing them to transmit signals that alter the brain's state. The brain transmits signals to the motor organs, which are capable of altering the environment -- hopefully in the way the brain intends. So the environment affects the brain and the brain affects the environment. Interacting with an environment is something that Turing machines don't do. So, it follows that the brain does not instantiate a Turing machine. It doesn't follow from this that the brain can't be simulated. Storing just a representation of the brain on a Turing machine tape is clearly misguided. But the above argument doesn't rule out the possibility of storing representations of the brain, and the relevant parts of the body and the environment on a Turing machine tape, and simulating all three together. Ie. maybe a Turing machine can simulate the brain, but only by simulating the things that the brain interacts with as well. The idea that the brain can be simulated does not imply that the brain instantiates a Turing machine. If Searle's argument depends on this implication being true, then it is flawed. -- David Canzi There are too many thick books about thin subjects.