Soul-Searching by Nicholas Humphrey (London: Chatto & Windus 1995) In 1991, Darwin College Cambridge was given a substantial bequest to fund a research post in parapsychology. The event became something of a cause célebre. Various Cambridge University academics objected to accepting this money: the professor of philosophy, D.H. Mellor, said on BBC radio that funding such a position would be like funding a research post to determine whether the earth is round. Other members of Darwin College were (understandably, perhaps) reluctant to turn down any offer of money for research. In the end the situation was resolved to the satisfaction of the sceptics: Nicholas Humphrey, psychologist and broadcaster, was given the post to research into the reasons why people believe in parapsychology. The present book is one result. Was the money well spent? Soul-Searching is a lively, entertaining book, packed with pointed quotations from literary and scientific sources. The actual upshot of Humphrey's research comes as no surprise: the reason people believe in parapsychological phenomena is because they want to believe in them, because they want to think there is something more to human beings than just the matter which makes them up. Belief in parapsychology is, like belief in the immortality of the soul, wishful thinking deriving from our inability to accept the brute facts of our material existence. This conclusion, though not in itself implausible, does not seem to be the product of extensive empirical research. Little of this book is the result of (say) interviews with parapsychologists, or opinion polls, and Humphrey does not even quote much from the works of parapsychologists. It is hard not to speculate that Humphrey knew what the outcome of his research would be even before he started. However, this is not in itself a criticism of the book, since Humphrey sets himself a larger task than simply explaining why people believe in parapsychology: the task of explaining why it is irrational to believe in it. Humphrey points out that there is a strange paradox at the heart of the parapsychological research programme. On the one hand, parapsychologists claim that they are just open-minded scientists trying to account for recalcitrant 'psi-phenomena'. But on the other hand, parapsychologists often show themselves already to be convinced that paranormal phenomena must, in John Beloff's words, 'forever defy scientific analysis'. And therein lies the peculiarity of the approach: success in parapsychology amounts to discovering things which cannot be explained! Humphrey is good at teasing out the contradictions and tensions in parapsychologists' claims. He also does a good job of underlining the curious and inexplicable banality of the supposed psi-phenomena: why can psychic powers bend spoons but not prevent air crashes? Less convincing is his insistence that a belief in an immaterial mind requires a commitment to the paranormal. For there are many ways of denying materialism-the vague philosophical doctrine that everything is material- without embracing parapsychology. And it would also be possible to hold (though few parapsychologists do) that psi-phenomena will ultimately be explained in terms of physical forces and laws. Materialism, then, is irrelevant: the issue is not whether parapsychological phenomena are inconsistent with materialism, but whether they are inconsistent with the facts, whatever they may be. The right way to approach claims about parapsychological phenomena, it seems to me, is David Hume's. In his essay, 'Of Miracles' (1748), Hume argued that given a report of a miracle, it is generally more reasonable to believe that someone somewhere is deluded than it is to believe that some fundamental law of nature has been disrupted. An advantage of this approach is that sceptics do not have to explain how the 'miracle' occurred, and nor do they have to prove them impossible. Rather, given that there is an explanation consistent with the laws of nature (in terms of the credulity of people) the apparent miracle can be dismissed. Humphrey is fully behind Hume here. But towards the end of the book, he raises the stakes in the argument against parapsychology, and attempts to argue not only that parapsychological phenomena are improbable given what we know, but also that they are logically impossible. That is, the crucial claim is not that psi-phenomena do not happen: it is that they cannot happen. This seems to me to be a mistake. It is one thing to say that something cannot happen given what we know about the world; but quite another to say that it cannot happen in any sense at all. The fact that we can imagine ESP and the like is evidence for the fact that they are possible; and the sceptic should not have to deny this. The case against parapsychology is strong enough, as Humphrey's book shows, without its having to establish the absolute impossibility of something which simply does not happen. Tim Crane Department of Philosophy University College London