Physicalism: the Philosophical Foundations by Jeffrey Poland Oxford: Clarendon Press 1994 ISBN 0 19 824980 2 viii + 378pp £35.00 The Reverend Anthony Freeman gained a brief moment of fame last year when he lost his parish because his bishop took him to be an unbeliever. The British national newspapers enjoyed the spectacle of an 'atheist vicar' for a while; however, Mr Freeman himself always denied that he was an atheist. One paper reported an interview with his local parish magazine, where Mr Freeman was asked directly whether he believed in God. Mr Freeman replied that of course he did, but that working out exactly what it means to believe in God was his life's work. It may not unreasonable to ask how one can be so confident in believing something when one does not know exactly what it is. We find a curious parallel to Mr Freeman's views in recent philosophical discussions of physicalism (the thesis that, in some sense, everything is physical). Chapter 3 of Jeffrey Poland's new exposition and defence of physicalism is called 'Identification of the Physical Bases'. The task Professor Poland sets himself here is that of spelling out in a principled way what 'physical' means, and to say this in a way that makes physicalism an illuminating doctrine. (For example, it would not be illuminating to be told that 'physical' applies to the subject matter of physics unless we are told in independent terms what physics is.) Poland claims, quite correctly, that this is one of the 'deepest foundational issues facing physicalists'. But as he says, the issue has 'been all but ignored by proponents of physicalism'. Poland does not point out what a peculiar state of affairs this is: many philosophers believe in physicalism, but few have said exactly what it means. The comparison with Anthony Freeman's case is irresistible: 'of course we believe in physicalism; but working out exactly what this means is our life's work'. Why should there be this problem of identifying the 'physical bases'? Part of the reason is because many modern physicalists want to avoid eliminating non-physical phenomena (notably, mental phenomena) from their theories. Earlier versions of physicalism tried to incorporate non-physical phenomena by identifying them with physical phenomena: mental states for example, are strictly identical with physicochemical states of the brain. This view collapsed some time in the 1970s under pressure from the so-called 'variable realisation' objection: it is empirically unlikely that all instances of (say) of the mental state of thinking about Vienna are identical to instances of the same brain state. Since then, physicalists have been looking for a way of 'basing' non-physical phenomena in physical phenomena without resorting to this discredited 'identity theory'. Hence the need to identify the 'physical bases': if physicalists want to base non-physical phenomena on physical phenomena, then they need to give some account of what these bases are. Professor Poland's book defends a version of physicalism along these lines, and anyone wanting a detailed exposition of this (fairly orthodox) view will want to read his book. The essence of the view is that physicalism is a programme for unifying knowledge based on the assumption that physical entities 'exhaust, determine and realise' all that there is. This view does not deny the existence of non-physical entities, or identify apparently non-physical entities with physical entities. What it does rule out are entities which have an existence independently of any physical basis (Poland's slogan: 'There are no ghosts!'). Physicalism has achieved such an orthodox status in English-speaking philosophy that it is a good thing to address the reasons for adopting it. Poland offers a fairly exhaustive survey of these reasons, some of which are more convincing than others. (He provides little defence, for example, for the remarkable claim that research in cognitive science 'cannot be made intelligible' unless we assume physicalism.) But what is missing from the book is any recognition that there are any viable alternatives to physicalism: that there can be any way of organising scientific knowledge which does not either collapse into physicalism or commit itself to the existence of 'ghosts'. For this reason at least, Poland's book is ultimately for initiates: those who have decided that they are physicalists, but want to know exactly what this means. Tim Crane University College London