Rosenblum, Bruce and Kuttner, Fred. Quantum Enigma: Physics Encounters Consciousness.

French, Steven

ROSENBLUM, Bruce and KUTTNER, Fred. Quantum Enigma: Physics Encounters Consciousness. Oxford: Oxford University Press, 2006. 211 pp. Cloth, $29.95--At the heart of the 'quantum enigma' lies the measurement problem. Put crudely, this runs as follows: the dynamics of quantum theory tells us that the state of a physical system is a superposition of possible states, yet when we make a measurement we always find the system in a definite state. What can explain this transition, or 'collapse' from a superposition to a definite state? Since the states of any further physical system that interacts with the system in question will themselves be incorporated by quantum mechanics into the superposition, it would appear that this transition cannot be accounted for in terms of physical interaction. Hence--again, putting things crudely--it was argued in the years immediately following the quantum revolution that the explanation had to be sought in the non-physical, namely consciousness.

Although often presented in popular discussions of quantum physics, this argument was demolished on philosophical grounds in the early 1960s, and physicists themselves have developed alternative responses to the problem, such as the Bohm interpretation and the infamous many worlds view. Recently, however, the possibility of delineating a role for consciousness has been raised again, and Rosenblum and Kuttner have hitched their horses to this revived bandwagon. Their book offers yet another popular account of the 'quantum enigma', in all its various guises: covering Bell's Theorem, the EPR 'paradox', the nature of superpositions, the two-slit experiment and so on, all nicely leavened with the usual 'history-lite' and some cute pseudo-Galilean dialogues to help explain what's going on.

However, what they do not do is delineate and defend an appropriate role for consciousness in this context. First of all, they fail to adequately critique and rule out alternative accounts. Thus to take the two mentioned above, the Bohm interpretation, in its most well-developed form, appears to leave no room for consciousness, invoking instead a form of hidden variable and quantum 'potential' to account for what we observe. The authors' response is to cite a comment from Bohm and Hiley in which they express the 'intuition' that consciousness and quantum mechanics are in some way related. But even leaving to one side the observation that Bohm and Hiley had quite idiosyncratic philosophical views, mere intuition is no substitute for an argument that this interpretation cannot avoid incorporating consciousness. No such argument is given, nor do the authors explore any of the standard objections to the Bohm interpretation. On the many worlds view, there is likewise no transition from a superposition to definite state, but rather a kind of division or splitting of reality along lines set down by the dynamics, so that each state in the apparent 'superposition' forms the basis for a different world. Here, the authors seem content to say only that it remains a fascinating basis for further speculation, without touching on any recent developments that have taken this view beyond speculation, or, again, considering any of the well-known objections.

Secondly, although they do outline Chalmers' much discussed position, their discussion of the nature of consciousness remains at the shallow end of the spectrum, even for a popular work. In particular they fail to tackle the central objection to presenting consciousness as a solution to the measurement problem, namely: how does the non-physical effect such a transition in the physical? It was this that lay behind the philosophical demolition job noted above. Of course, there are ways of getting around such objections. Interestingly, one of the earlier defences of the role of consciousness--the London-Bauer account, typically but erroneously regarded as a mere summary of the 'standard' view--gives an intriguing and radical phenomenological interpretation which dissolves the distinction between the physical and consciousness to begin with. Of course, this is a problematic line to take but it is surely beyond time to consider such alternative accounts and determine what we might learn from them.

Relatedly and finally, the authors never really show how it is that consciousness bears on quantum physics. Again to be crude, their account amounts to little more than placing the 'quantum enigma' up against the 'mystery of consciousness' and waving their hands over them! Although its good to see consciousness brought back out of the shadows, if it is going to survive in the harsh light of day its going to need more subtle and sophisticated treatment than this.--Steven French, University of Leeds.