Evaluation of Identity Theory And

"What is it to perceive, to feel emotion, to hold a belief, or to have a purpose?" asks Armstrong (225). Do we have a soul, or are we purely physical? Are these questions even mutually exclusive? The Identity Theorist argues that the mind is completely physical on the grounds that mental states and brain states causally interact and therefore, mental states must be brain states. Although one may object that it could be possible for the mind and body to interact without being identical, Identity Theorists adequately argue that we should believe the simplest explanation of everything.

The Identity Theorist believes that science and philosophy must work together in order for us to see the whole picture of the mind. On their own, each comes up with an incomplete idea of the nature of the human mind. According to Armstrong, as philosophers, we must not leave out scientific methods, and must consider a scientific consensus to be reliable. The scientific consensus about the human mind is a Materialist account, which suggests that everything in the world is material. Therefore, the mind is entirely physico-chemical, and all behaviors, experiences and sensations can be explained by brain processes in the central nervous system. J.J.C. Smart argued that sensations are identical with brain processes. Identity Theorists use identity in the strict sense of the word; when Smart claims that sensations are brain processes, he does not mean that they are of the same type of thing, but that they are numerically identical. "When I say that sensation is a brain processÐ'...I do not mean just that the sensation is somehow spatially or temporally continuous with the brain processÐ'..." explains Smart (235). Some believe that consciousness is an exception to Materialism, and that consciousness is "over and above" brain processes. Smart replies to this with an ad absurdum argument of sorts, that it is highly unlikely that only sensations should be the only exception to laws of nature. While he believes it is possible for scientists to discover new laws, he claims that these novel laws will have the same components as the laws that have already been proven.

Smart does not think that sensations and brain processes are interchangeable, but that sensations are types of brain processes. He uses the example of a man who is also a doctor. If a person says "some person was in the room" and another person says, "a doctor was in the room," this does not mean that there are two people in the room, or that the terms "some person" and "doctor" are synonymous; however, the term doctor meets the requirement of "some person." Similarly, while brain processes and sensations are not the same thing, sensations meet the requirement of being a brain process. This belief is a posteriori, for it can be discovered through scientific means that perceptions are of a physical nature. While the technology may not exist to prove the physicality of sensations, it is theoretically possible to prove or disprove.

Identity Theory solves the problem of mental causation. It has always been a question how something nonphysical, as in the mind, can cause something physical to happen in the body. This is not a problem if the mind is physical, for it follows physico-chemical laws.

Descartes would object that it is possible for the mind