How Brains Make Up Their Minds

Walter J. Freeman

Weidenfeld & Nicolson, London, 180pp, £14.99 (hardback)

ISBN 0-297-84257-9

Published 1999

How do the chemicals and electrical impulses of our brains support the sense of free will so central to our feeling of "self"? The author brings over forty years of experience studying the workings of the brain to bear upon this age-old philosophical question. This book should be of interest to neuroscientists, cognitive psychologists and philosophers, and is structured in a way that should make it accessible to all those prepared to assimilate the necessary neurobiological detail while following challenging philosophical arguments. The first two chapters discuss the philosophical issues of intentionality and meaning, and the following two introduce the concepts of dynamical systems in graphical fashion in the context of neuron populations and perception. In the remaining three chapters the author attempts to weave these two strands together, and it is here that for me the book loses its way. In extrapolating from his own work on the olfactory system to questions of awareness, consciousness and causality, the author necessarily takes some bold steps. The author takes a stand against the extreme but prevalent neuro-reductionist perspective which aims to relate percepts, decisions and behaviours to the activities of single cells. Central to his argument is the notion that treating the brain as a chaotic dynamical system can provide insight into the way that meaning is embodied in patterns of neuronal activity. However, while the dynamical systems approach to understanding brain function may furnish cognitive science with some evocative metaphors, in these pages it is elevated to an almost mystical status. Evolving patterns of brain activity are identified with cognitive states in a manner that fails to distinguish matters of established scientific fact from wild speculation. It is clear that somewhere between the activity of single cells and the activity of whole brains something remarkable is happening. However, these days the notion of emergent properties in complex systems is as familiar to neuroscientists as it has been to sociologists since Durkheim: the whole is qualitatively more than the sum of its parts. Can viewing the brain as a chaotic dynamical system help us to appreciate the nature of "emergence"? Perhaps, but the case put forward here is unconvincing. One point that does not come across clearly is that chaos is not an escape from determinism. A small perturbation in initial conditions can greatly effect the evolution of chaotic system through time, but once those conditions are established the future of a chaotic system is just as completely determined as that of a non-chaotic system. Chaotic system or not, the paradox remains that although our brains are composed of matter obeying deterministic physical laws, we think of ourselves as causal agents capable of exercising free will. While studying the dynamics of neuronal populations does promise to reveal more about the nature of consciousness than considering the effects of quantum fluctuations on dendritic computation, the book falls short of its stated aim of making clear how findings from neuroscience strengthen ideas concerning self determination and individual responsibility.