In this book, Nick Humphrey, presents his theory of consciousness. Actually, one would do better to call it a theory of qualia. It is a summary-extension of his earlier views, presented clearly in his book 'A History of the Mind'. The paper is ambitiously called "how to solve the mind body problem". Now, the question in everyone who would like to read this book, is, does Humphrey really solve the mind body problem? Of course not! and as proof, note that only the first 20 pages concern Humphrey's theory, the rest being commentary-critiques, where no real sign of agreement appears. HOwever, there is a much more subtle and by no means less important question to ask: does this book make progress in the mind body problem? Of course it does! Humphrey's theory is a very, very plausible one. Some would say that he just presents an evolutionary 'just-so story' or that he adresses the problem of qualia, and not consciousness itself, but these are not weaknesses but areas of possible expansion, taking the theory as foundation.
Humphrey mantains, rightly, that the problem of qualia is a problem of making the identity 'brain state P= mental state S' look natural. He holds that it is not enough to balance one side of the equation without balancing the other side as well. Not only must we redefine the neural component, but the qualia component as well. Now Humphrey takes a functional aim, however. But it is evident that a functional explanation leads inevitably to the physicalistic explanation, that of the "mind-brain" identity. He discusses the diferences and relationship between perception and sensation, then presents an evolutionary story that will facilitate the making sense of how matter could indeed become conscious.
Humphrey's theory is not without its faults, and the commentators realize this. But it is a good sign when the most serious objection is a philosophical one: could not all of what Humphrey's talks about happen, but without the qualia? Here come the zombies again! Now I must admit that it is true that Humphrey's does not make the puzzle disapear. It is still a mystery how is it that qualia emerges from lifeless, grey, matter. But at lleast, (and this is a great step, if you consider consciousness debates) it is at least possible to see how the puzzle COULD be put together, without falling into mysterianism, nor any kind of dualism. As a theory of qualia, I doubt any others come close. But this is just a small step for man. The giant step will have to waita bit. Consciousness is still not explained, and it is a routine to say this. But it would be false to say that no progress has been done.
This book should be read by anyone interested in the mind body problem, because Humphrey could, with a little bit of luck,be the one to hammer the first nail of the very large coffin of the mind body problem.