Reading

[Required] Lecture notes from James Pyror
[Required] Searle, John. R. (1980) "Minds, brains, and programs" Behavioral and Brain Sciences 3 (3): 417-457.
Section 11.6, Chapter 11 of Osherson, Daniel N.; Gleitman, Lila R. (1995) An Invitation to Cognitive Science. Vol. 3, Thinking Cambridge, Mass. MIT Press.
Searle, John. R. (1990) "Is the Brain's Mind a Computer Program?" Scientific American, vol. 262, pp. 26-31.

What the issues are

The real issue is not

Whether machines can think. (We are after all "meat-machines".)
Whether a computer can simulate the mind. (Maybe it still cannot think.)
Whether the mind is a computer. (Maybe, but maybe that's not why we can think.)

The central issue

The real issue is whether the right kind of computation / program is sufficient for having a mind. Does something think in virtue of having the right software?
This is what Searle calls "Strong Artificial Intelligence" (Strong AI).
Weak AI says, "computer models are useful in studying the mind." This however admits of two interpretations, (1) computers can simulate mental processes, and (2) the mind has a computational level of description. (2) is stronger than (1).

The Chinese Room Argument

(1) Suppose it is possible to have a program that produces understanding of Chinese.
(2) In principle a person in the Chinese room can carry out such a program.
(3) But such a person would not understand Chinese.
(4) Therefore, it is not possible to have a program that produces understanding of Chinese.

This is a reductio argument.

The Churchlands' response - Deny premise (2)

Serial computations are not sufficient for understanding. Parallel computations are needed.
Searle : not sure why it makes a difference. Change to example to the Chinese gym.
Presumably what can be done in parallel can be done in serial.

The Unconscious Understander - Deny (3)

The person does understand Chinese, although he does not know this because he lacks conscious awareness of his knowledge of Chinese.
But how can someone knows a language without knowing that he knows it? Knowledge should be accessible to consciousness in principle.

The robot reply

A robot with the program inside allowing it to interact with people and the environment would have understanding.
Comment #1 : Agree with Searle then. Program not sufficient. Requires embedding.
Comment #2 : Why think that embedding helps? Behaviorism?
Searle : Putting Searle in the robot does not make Searle understands Chinese.

I am receiving "information" from the robot's "perceptual" apparatus, and I am giving out "instructions" to its motor apparatus without knowing either of these facts. ... I don't know what's going on. I don't understand anything except the rules for symbol manipulation. Now in this case I want to say that the robot has no intentional states at all.

The System reply - The argument is not valid

True : the person (as the processor of the whole system) does not understand Chinese.
It does not follow that the system as a whole (person + books + symbols) does not understand Chinese.
The understanding generated by the execution of the program might reside in the system and not the processor.
Searle : But imagine a case where the person is the system by internalizing the rules and everything into his memory.
All the same, he understands nothing of the Chinese, and a fortiori neither does the system, because there isn't anything in the system that isn't in him. If he doesn't understand, then there is no way that the system could understand because the system is just a part of him.
Rejoinder : still he is not the whole system.

An analogy - computer emulation

Some examples of emulator projects:

Emulation vs. virtualization - In virtualization, the hardware is partitioned in a way that allows more than one operating system to run simultaneously. Each OS and its applications run on the native hardware, with the instructions being executed natively by the processor. However, in emulation, the processor simulates a processor and other subsystems in software.

Examples from VMWare

What is Missing?

Searle does not say that only biological systems can think, but he thinks that programs alone do not produce thinking because they lack the right kind of biochemical properties. He does not elaborate and this seems to be mere speculation. Searle's Argument is used to support this general argument against Strong AI :

(A) Computer programs are formal (syntactic).
(B) Thoughts and understanding have content (semantics).
(C) Syntax by itself is neither constitutive nor sufficient for semantics.
(D) So computer programs are not constitutive or sufficient for thinking or understanding.