The Conscious Mind In Search of a Fundamental Theory David J. Chalmers Oxford University Press, 1996, 414 pages.

In Part I, Foundations, Chalmers describes the concept of supervenience and describes what he means by consciousness, which for the author is the subjective component of experience (the "hard problem"), as distinct from perception and pattern recognition of sensory input (the "easy problem" - or perhaps more accurately, "someone else's problem"). Perhaps an even harder problem is convincing people that there is a fundamental problem to be solved. The multiplicity of phenomena attached to the label 'consciousness' over the years makes this problem more difficult for Chalmers, who occasionally even seems to get confused himself, and frequently gets distracted.

In Part II, the main ideas are presented. The author tries to prove his main thesis, that consciousness cannot be reduced to material processes, using various arguments. This can not have been easy, given the difficulties defining the concept of consciousness in Part I. Five arguments are made:

1. 'Zombies' , i.e., beings like humans in every respect except that they lack consciousness, Chalmers says, are logically impossible. This is basically a reversed Turing test argument, and in my opinion it fails for the same reason, namely that there is no definitive way of actually determining whether consciousness is present. That is, there is no test to determine whether zombies, a computer, Searle's Chinese room, or for that matter, a thermostat, all of which process information of one sort or another, are experiencing anything or not. In fact, if there were such a test, the answer to "what is consciousness" would be already at hand, as the problem could then be addressed experimentally.
2. 'Inverted spectrum' (or inverted qualia) - Can there be a duplicate of oneself that experiences red instead of blue, for instance. Chalmers says no. This is merely a perception issue and does not relate to the 'hard' problem of consciousness he intended to discuss. Moreover it presupposes that there is something unique about perceiving redness compared to blueness, an assumption many biologists would undoubtedly dispute.
3. 'Epistemic asymmetry' - Consciousness is not obvious from analysis of molecules or neurons, yet we are still aware of it. Therefore, says Chalmers, it is not logically supervenient on them, i.e. consciousness cannot be explained by understanding the behavior of molecules or neurons. This is non-tautologous only if one adopts a dualistic viewpoint. A non-dualist would probably rephrase this as 'okay, we need a theory'.
4. 'The knowledge argument' - One needs to have perceived red to know what perceiving red is like. Again, this is a perceptual issue and is irrelevant to the problem of consciousness.
5. 'Absence of scientific knowledge on consciousness' - Since science has never successfully investigated consciousness, says Chalmers, the concept of consciousness is irreducible and cannot be explained in terms of any other phenomenon. This argument is self-evidently invalid.

Although the arguments seem to be mostly logically invalid or at best unconvincing, the author plows forward, building on the belief that consciousness is not reducible to simpler physical phenomena. If this point could be firmly established, it would be a discovery with profound implications; but the arguments put forward are not precise or compelling enough to convince many readers. "Reductionism" is also apparently a derogatory term for Chalmers, and he spends a lot of time criticizing the reductionist approach.

The author bases the remainder of the book on the conclusion, based on the arguments in Part II, that consciousness is "naturally" but not "logically" supervenient to any physical phenomena. Needless to say, this conclusion that consciousness is unexplainable leads the author into a property-dualistic philosophy, in which conscious experience is considered to be totally distinct from brain activity.

Part III describes the author's ideas toward a theory of consciousness. This section, like Part I, gets a little verbose, for example by belaboring at great length the minor question of whether "consciousness" and "awareness" are the same. Chalmers does not actually develop any sort of theory in the scientific sense, but mainly discusses what other philosophers have said on the subject, and then engages in unrestrained speculation, using arguments by analogy and intuitive judgments to determine their plausibility, on topics such as possible connections between information flow and consciousness. For instance, Chalmers asks whether thermostats might possess a rudimentary consciousness because of their information processing capability. This is a fascinating question, but considering the current impossibility of actually measuring consciousness or any other subjective phenomenon, wild speculation is about all that can be done at this point. One is left with the feeling that something more radical, fundamental, and unconventional is needed.

Part IV, 'Applications' discusses the author's speculations and thoughts on artificial intelligence and quantum mechanics. This is the most interesting part of the book, and gives an overview in very general terms of why some physicists think QM may shed light on consciousness, unfortunately without describing any of the actual experiments that lead them to this conclusion.

The main contribution of this book is its argument that a phenomenon of consciousness exists that is currently neither understood by science nor explainable by any current theory or conceptual framework. Many people, including at times, the author of this book, tend to get 'consciousness' confused with 'perception' and other cognitive phenomena. It is a fuzzy, slippery word. Much (or maybe all) of what people call 'consciousness' is an artificial construct invented by the brain to explain its own actions. Chalmers is one of the few authors to realize that the more difficult problem of explaining subjectivity is not addressed by neurophysiology, anatomy, or biochemistry. Indeed, he is compelled to spend much of the book arguing this point, as there are many influential people out there who do not believe it (Dennett, for example). Unfortunately, this leaves little energy or space for actually developing a coherent theory, and it is perhaps not surprising that the uncertain basis described above does not lead very far toward a theory of consciousness.

Finally, a minor problem is that the book is also full of politically-correct "she"s and "her"s. Now that most writers are finally settling on the use of "they" for a 3rd person singular gender-indeterminate personal pronoun, the continued use of the feminists' P.C. style only detracts from the book's readability.