So that's it. A sophisticated enough parallel processing computer would just like a brain, right?

• The words "sophisticated enough" refer to a computer--perhaps a massively parallel supercomputer--that will have lots and lots of complex internal interconnections, as well as the ability to self-modify its programming. We're not nearly there yet, but it seems realistic enough to imagine it can/will happen sometime far in the future. The point is, it seems theoretically possible, given all the arguments presented to this point.

The philosopher of mind John Searle does not agree. He makes a theoretical argument that a computer and its programs is not like a human brain. This is done in his now famous example called the Chinese Room. A statement of the argument is in the MIT Encyclopedia of Cognitive Science, from which the following is quoted:

• " The argument proceeds by the following thought experiment. Imagine a native English speaker who knows no Chinese locked in a room full of boxes of Chinese symbols (a data base) together with a book of instructions for manipulating the symbols (the program). Imagine that people outside the room send in other Chinese symbols which, unknown to the person in the room, are questions in Chinese (the input). And imagine that by following the instructions in the program the man in the room is able to pass out Chinese symbols which are correct answers to the questions (the output). The program enables the person in the room to pass the Turing Test for understanding Chinese but he does not understand a word of Chinese."

"The point of the argument is this: if the man in the room does not understand Chinese on the basis of implementing the appropriate program for understanding Chinese then neither does any other digital computer solely on that basis because no computer, qua computer, has anything the man does not have."

Or to put it another way, Searle argues that while a computer program has syntax, a set of grammatical rules that interrelate its operations, it does not have any semantics. Semantics are notions of meaning that we humans have about the words we use. When a computer program manipulates the word 'foot' it does not know that it is dealing with an anatomical appendage or perhaps a measure of distance. Not only does it not know, Searle asserts that there is nothing about a computer that could let it come to know.