Here is what I make of what is going on in this unit of the course, dealing with the mind. This is my attempt to summarize the issues, and to lead in the direction of a useful essay topic for the class to work on.
Background
The whole discussion is based on the assumption that we all have a mental life. That is, that we have thoughts, emotions, desires, and the like, and we have abilities that are referred to as intelligent -- for example, we can use a complex language to express ideas and to communicate, and we can solve reasonably complex problems.
But there is also an assumption that there are problems about explaining exactly what it is to have a mental life--what it is to think, to emote, to desire, to have some degree of intelligence or rationality, and the like. The reason that there are problems about this topic is that traditionally each person's mental life has been thought to be not directly observable by others. That makes it hard to study in any reliable way. True, we can ask other people what they are thinking or feeling, but they don't have to tell us the truth, and we have reason to think that sometimes they may not even know the answer themselves. That is, our mental lives may seem to be rather hidden from view, and thus very difficult to examine.
This difficulty is brought to the fore by cases like the Terri Schiavo case (the "woman" in the persistent vegitative state, who was in the news not too long ago when there was dispute about whether to let her remaining body die). In that case, the family members did not agree at all about whether there was a mental life going on "in" her. These puzzles are related to the abortion dispute as well, since part of that dispute centers on questions about whether the developing fetus has a mental life, and if so, what sort of mental life at various stages of its growth.
Theories
In order to try to deal with the general questions about our mental lives, such as those raised above, various theories have been proposed, such as Cartesian dualism, behaviorism, and so on. Here is a way to understand what these theories are getting at: they are all attempts to answer the question, What are you?
What are you? Not, who are you. But, what are you? If you had to answer that question, what would you say?
Here is one style of answer that has become popular in recent decades among researchers:
You are a complex living organism with a brain that is capable of learning to direct complex behaviors such as language use and morally-sensitive interactions with others.
Notice that this style of answer leaves out any mention of a private mental life. So, to many folks, this type of answer leaves out some crucial aspects of what they are -- the "mental" aspects, such as "consciousness", feelings, perceptions, soul (?). It leaves out the aspects that Prof. Deutsch calls "subjective".
In fact, leaving out anything that counts as subjective is exactly the point of the various materialist theories of the mind, such as behaviorism and materialist functionalism. These theories are specifically designed to avoid mentioning anything that cannot be studied empirically (through observations). These theories are designed to take the mystery and subjectivity out of the discussion of what we are. They are thus seen as more "scientific".
The sample account given above is an example of a materialist account. It sounds like some sort of functionalist view to me.
But what then happens to the "mental" aspects of who we are? Do they just get ignored? Not exactly. Each of the materialist theories tries to account as much as possible for our mental life, but obviously the accounts have to be given in terms that are not subjective. This has proved to be difficult and controversial. The mind-brain identity theories were some of the first attempts to make this work. The functionalist theories are the more recent ones, and these seem to work better than the mind-brain identity theories, but they are still controversial and incomplete. For example, Searle does not believe that any functionalist theory can be the complete story of our mental lives, no matter how well the theory might be developed. His Chinese Room argument is a key part of his strategy to try to prove that functionalism cannot be the whole story of the mind.
How does a materialist theory of the mind, such as functionalism, try to account for our mental lives without referring to anything subjective? By "reducing" mental states to functional states. This means that the functionalist theory will claim that the various mental states such as feeling a pain or thinking of one's childhood are "nothing more than" various functional states of the physical organism--typically thought of as functional states of the organism's brain.
So, the challenge faced by a materialist functionalist theory of the mind is to explain exactly how mental states can be understood to be nothing more than functional states of the organism.
When there is some mental state that seems to be incapable of being understood as a functional state, such as the state of being consciously aware of oneself, the functionalist theory may well deny that such states exist at all, or that they are worth studying. That is, there will be a strong temptation to "write off" any aspect of our mental life that is not "reducible" to functional states of a physical organism, since these aspects will be seen as too subjective to be taken seriously in a scientific account of the mind. This is where the quote that Prof. Deutsch displayed in lecture comes in: consciousness is said to be an "evanescent illusion" -- something not worth taking seriously.
But the functionalist theories would not gain much support if they treated everything about our mental lives as unreal or not worth studying. So, in fact, materialist functionalist theories attempt to account for a great deal of what has typically been thought to be mental -- especially, functionalist theories have attempted to account for things like what it is for you to understand something. Understanding things has been thought to be an important part of our mental lives. If one could explain in functionalist terms what it means for an organism to understand things, that would be a big step forward in the process of functionalist theory building.
This is where the Turing Test comes in. Turing proposes a functional definition of what it means to understand a human language. Essentially, Turing is saying that an organism or a machine understands a language if it can function linguistically in the same way that a normal human speaker of the language does. That is, it can say things that seem like the sorts of things that normal human speakers would say in conversational situations in response to questions. In order to drive the point home, this means that even if the language-generator happens to be a digital computer, the computer will be said to understand the language if it can pass the test. It will also be said to possess a form of "intelligence". That is, a computer that handles the use of the language in conversation well enough is said to be intelligent. Perhaps this means one could also say that the system knows things, or has beliefs, or thoughts.
Please don't lose sight of the fact that all of this is intended to explain in functional terms what it means to be intelligent or to understand a language. So, it's not just about computers. It's about YOU. Your intelligence and understanding is what is being defined by the functionalist theories. The computer model is just a device for illustrating and arguing for the materialist functionalist view of the mind.
Now, it is true that the Turing Test was never proposed as a test for all aspects of the mind. That is, if a computer can pass the test, Turing would not jump to the conclusion that it has emotions, or can fall in love, or that it feels pain or pleasure. The Turing Test is not a test for being a normal human mind; it is limited to being a test for linguistic understanding and the accompanying label "intelligent", and perhaps other related labels, such as "having beliefs".
But even though the Turing Test is limited in its claims, it is still very troubling to many. (It troubles Searle, for example.) The question is whether it really is true that a machine that can pass the Turing Test really can be said to understand anything at all, whether it can be said to be intelligent, to know or believe.
Searle proposed the Chinese Room argument to try to demonstrate once and for all that passing the Turing Test does not mean that the machine understands, knows, believes, thinks. This again is not really about computers. It's about YOU. Searle is saying that for YOU to understand something is not merely for you to be able to manipulate linguistic elements so as to pass the Turing Test. There is more to understanding than that. There is more to having beliefs. (According to Searle's argument.)
But is the Chinese Room argument actually a good argument? Should we be convinced by it? This is worth talking about. Prof. Deutsch unfortunately did not get to the criticism of the argument. The criticism that may carry some weight against the Chinese Room argument is mentioned by Searle on page 70 -- the "Systems Reply". We will talk about this in class.
There is also another attack on the Turing Test, called the Brute Force argument. Prof. Deutsch mentioned this in class. We will talk about this argument as well. It is perhaps more powerful than the Chinese Room argument.