JOHN SEARLE is clear, challenging and profound, and his book The Mystery of Consciousness (Granta, £9.99, ISBN 1862070741) reflects its author. It offers an engaging debate between Searle and David Chalmers, Daniel Dennett, Roger Penrose and Israel Rosenfield. Searle also touches on the work of Gerald Edelman and Francis Crick.
Searle’s main thesis is that consciousness is a unique feature of brain processes, but not reducible to the goings-on of individual neurons, in the same sense that the transparency of water is an emergent feature of water not reducible to the features of individual water molecules.
He insists that the mind cannot be understood as simply a program running on a computer called the brain. Brains do compute, but they do more. Computers simply manipulate symbols without understanding their meaning.
Yet Searle does not always hit the target. For example, he confuses giving an explanation with giving an ultimate explanation in criticising Edelman’s contention that a brain process called “reentry mapping” gives rise to consciousness. Searle argues that, even if true, this does not tell us how the process gives rise to consciousness. But this is a higher-level question. You may explain why a ball thrown horizontally from a building reaches the ground at the same time as a ball that falls straight down by saying that the vertical acceleration due to gravity is a constant, independent of the horizontal speed. To say that one could say is to offer no criticism but only to ask for deeper, more general explanations.