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Under The Microscope

EVOLVING THE MIND -- ON THE NATURE OF MATTER AND THE ORIGIN OF CONSCIOUSNESS by A.G. Cairns-Smith; Cambridge University Press, 1996; 329 pp; $36.35 paperback, $55.95 hardback

Reviewed by Craig Webster

Cairns-Smith is a reader in Chemistry at the University of Glasgow and so understandably his approach to the topic of consciousness is a very chemical one. The book starts with a discussion of chemistry and physics, moves on to DNA and cellular mechanics, then primitive organisms, before discussing neural behaviour and consciousness itself. Everything is presented in a clear, fluent way with plenty of diagrams, so this book is easy to read and understand -- but at the same time doesn't skimp on detail.

It is unusual to have a discussion of simple inorganic chemistry and the complexities of DNA replication in the same book and I enjoyed the logical progression from one to the next. The physical complexities of individual atoms seem complex enough when their quantum nature is considered, but this pales in comparison with the incredible complexity of DNA. If the information content alone in the human genome were written out (something it will soon be possible to do), it would fill a book of about a million pages.

The author presents us with the idea that an increasing complexity of behaviour, the pinnacle of which is human consciousness, is a result of an increase in the complexity of the underlying chemical machinery. Proteins can fold into specialised machines by virtue of their chemical makeup and hordes of such protein-machines carry out the vast number of chores required to keep a cell functioning. Simple organisms like E. coli consist of many cells, but seem more like little robots than living things since their behavioural repertoire is so limited, albeit highly effective for their own purposes.

Our brain represents many more steps up in chemical complexity, but Cairns-Smith claims that there is more going on here than merely massive interaction between a huge number of specialised neural cells. He claims that neurons are so precisely specialised that they are capable of tapping into some of the most basic physical properties of matter -- namely quantum effects -- bringing the book back to its opening chapters' discussion of the physical nature of matter. While this is an elegant argument, ultimately I believe it does not convince -- it seems overly fashionable and lacking evidence.

The history of the philosophy of mind is littered with metaphors for consciousness based on the topical technology of the day. The brain has been seen as a hydraulic device, a telephone exchange, a digital computer and now Cairns-Smith proposes the metaphor of the very latest quantum physical phenomenon -- a Bose-Einstein condensate. This weak conclusion does not detract from the rest of the interesting discussion in the book and anyone with an interest in cognitive science or the philosophy of mind would enjoy it.

Craig Webster is currently a clinical researcher in the Anaesthetics Department at Auckland's Green Lane Hospital.