The computational theory of mind was brought up in a response to my other post on physicalism. This is a view that I personally believe can be utterly devastated by even a cursory examination through analytic philosophy.
The Computational Theory of Mind (CTM) essentially states that the mind can be likened unto a computer. This view is also known as the software view of Functionalism. It is the belief that the mind is essentially a computer program. Inputs are fed in, outputs are fed, well, out. The mind can be exhaustively described in these kind of relations. Sensory inputs, behavioral outputs, etc.
This is yet another way for atheists to try to escape the nasty mind-body problem.
There are several objections that can be raised against this view. The first is that the Functionalist/CTM view focuses on defining mental states through causal relations such as the outputs of behavior rather than the internal traits of the mental state itself. In other words, Functionalists could see two mental states as identical when they are not. An example could be the classic problem in philosophy about color.
Suppose Bob and Sally enter a room with various objects scattered about and they are told to find all the objects which are green and put them in a pile. Internally, Sally is able to sense color normally, but Bob is not. However, because they are both supposed to be in the state of sensing greenness, they are both functionally in the same mental state. But Bob senses all green objects as red, and all red objects as green. Therefore, internally, he and Sally are in different mental states, but because they sort the objects in the same way (Bob has always seen green as red, so when told to sort green objects, he picks out those which are red to him), they are in the same mental state according to functionalism.
Analytically, the problem is then that CTM/Functionalism would state that:
If there are two persons who have input x=> output B, then they are in the same mental state.
But it misses the possibility that input x could be A for person 1 but culd be C for person 2.
Thus, Functionalism would state that A and C are identical, despite the fact that they are not, because it has no way of explaining the inverted qualia (specific experiential qualities).
Further, there is the classic Chinese Room example given by John Searle in “Minds, Brains, and Science.” Summed up, the Chinese Room states that one who has no understanding of Chinese could be in a room in which inputs are given in the form of Chinese characters on sheets of paper. This person has access to a book that gives appropriate responses to these Chinese characters. He or she then selects the appropriate response, enscribes it onto a sheet of paper, and puts it through the output slot. Now suppose the rulebook is so accurate that it can make it seem as though the person always has appropriate, even perfect responses to questions, small talk, etc. in Chinese. The person could then emulate entirely the ability to speak Chinese despite having absolutely no understanding of Chinese whatsoever.
This problem comes up within CTM/Functionalism because it discounts anything but the inputs and outputs. Functionalism/CTM would have to state that this person does literally understand Chinese, but that isn’t the case.
There are, as always, more ways to tear down CTM/Functionalism, but I believe that is good enough for now. As an alternative to dualism, CTM/Functionalism lacks utterly any explanatory power in terms of internalization, inverted qualia, and absent qualia. Adherents to CTM or Functionalism believe that it has better explanatory power. This is false.
Dualism, on the other hand, has explanatory power in terms of all of these. The acknowledgement of a mind that has understanding, direct access to inverted qualia, and can sort through actual mental states, so Dualism does not fail in the sense of absent qualia.
John Searle states it well, “Earlier materialists argued that there aren’t any such things as separate mental phenomena, because mental phenomena are identical with brain states. More recent materialists argue that there aren’t any such things as separate mental phenomena because they are not identical with brain states. I find this pattern very revealing, and what it reveals is an urge to get rid of mental phenomena at any cost.”
Moreland, J.P. & William Lane Craig. “Philosophical Foundations for a Christian Worldview.”Intervarsity Press.2003.