Body And Soul

Mind-body dualism or how the brain works and the mystery of consciousness is a happening area in science and philosophy today. The debate is mainly led by two groups: the dualists, who think there are two fundamentally different kinds of phenomena in the world (minds and bodies); and monists, who hold that the world is made up of one kind. John Searle, professor of philosophy at the University of California, examines the debate along with the exchanges he has had with prominent contemporaries, Daniel Dennett and David Chalmers, in The Mystery of Consciousness (Granta Books, special Indian price, £7.99).

The debate has led to further splits in the academic world. Dualists divide into substance dualists who think mind and body name two kinds of substances, and property dualists who think mental and physical name properties in a way that enables the same substance the human being, for example to have both properties at once. Monists, in turn, divide into idealists, who think everything is mental, and materialists, who think everything physical.

Most people accept some form of dualism they think they have both a mind and a body, or a soul and a body. But Searle tells us that most professionals in philosophy, psychology, artificial intelligence, neurobiology and cognitive science accept some version of materialism because they believe that that is the only philosophy consistent with contemporary world views. Of course, the materialists have a problem: once the material facts are described, there are still a lot of mental phenomena (beliefs, desires, pains) left over.

Searle goes on to provide the background of the 20th century effort to offer a materialistic reduction of the mind, or behaviourism, which described just bodily movements. Speech behaviour, for example, was only a matter of voices coming out of ones mouth. Behaviourism was obviously false simply because there were different kinds of pain. As G K Ogden and I A Richards said in The Meaning of Meaning, to believe in behaviourism you have to be affecting general anaesthesia.

The difficulties of behaviourism has led to functionalism, which has become the most widely held theory of the relation between mind and body. Its proponents have it that mental states are physical states, but they are mental not because of their physical constitution but because of their causal relations.

Searle discusses the arguments of philosophers such as Francis Crick, Roger Penrose, Gerald Edelman, Daniel Dennett, Israel Rosenfield and David Chalmers. He challenges their claims that the brain can be represented and reproduced by computer programmes, and that consciousness can be reduced to a series of steps like those needed for designing a computer.

Searle believes that neurosciences would help to understand the problem of consciousness which arise from the activities of neutrons and other components of the brain. Consciousness is above all, a biological phenomenon, like digestion and photosynthesis and it is the biology that has to be understood before we can understand what gives rise to states of consciousness.