When Hegel sat down to write his Phenomenology of Mind, almost two hundred years ago, his agenda was clear. He would begin from the consciousness of elementary sensations and perceptions, and end up with the self-consciousness of the Absolute Spirit. Nobody would take up such a task today, if only because it is hard to say what Absolute Spirit means (but watch out for surprises). In any event, surely some order can always help.

This idea was evidently not in the mind/brain of Stuart Hameroff (anesthesiology and psychology), Alfred Kaszniak (psychology), and David Chalmers (philosophy), all professors at the University of Arizona, when they set out to present thirty-nine papers selected from the proceedings of the third interdisciplinary conference, “Towards a Science of Consciousness,” held in Tucson, Az., in April 1998. Needless to say, there are many ways to skin a cat, and certainly one does not need to be a Hegelian, but the layout of the collection is confusing at least to this reviewer. The reason is that its nine sections are arranged neither by levels of consciousness, nor by topic, nor again by discipline, but in a puzzling series that switches from one dimension to another. Thus the reader finds a section on philosophical analysis, another on color (including papers by philosophers), one on emotion (entirely by neuroscientists), another on evolutionary theory (including chapters on sensory qualitative states), and so on. But forget the order of presentation, and you will find — most of the time, not always — little treasures of scholarship and experimental research. The confusion, after all, may be a developmental trait of the “young” field of consciousness studies, which in recent years has been tackling very old issues in psychology and philosophy.

It is with philosophy that the book begins, specifically with a section devoted to the so-called “explanatory gap” between the natural sciences and the phenomenon of consciousness – in the very limited but currently widespread sense of sensory experience. The idea of the explanatory gap was introduced by J. Levine in 1983, and here he elaborates on his position. Now one should stop for a moment and recall that for some philosophers (none of whom has contributed to this collection) the “gap” does not exist at all. Having done that, the reader will find three other good chapters (notably Van Gulick’s) which accept the “gap” but tell us in various ways not to worry: there are no good metaphysical reasons to think that consciousness is nonphysical, although there may be reasons to think that experience is part of reality.

If consciousness is conceived as sensory experience, one is likely to find much attention devoted to the various sensory modalities, beginning with vision. Color is important in the field because philosophers have wondered if the conscious sense of red might be irreducible to a certain quantitative activation of the visual cortex in the brain caused by light of a given wavelength; and they have also wondered for centuries, after John Locke raised the issue in 1690, whether I may be seeing green when I look at a ripe tomato, while you may never find out because my mother taught me to call that red. Do inverted color experiences defy the scientific explanation of ordinary behavior? Larry Hardin, a philosopher who specializes in theories of vision and color, argues in an excellent chapter that once you go into the details the “inverted spectrum” turns out to be impossible, and this is good news for science. But other articles show that the debate is by no means over, and that more work is needed to reach a complete explanation of color vision including subjective experience.

Probably the most important result of recent studies of vision in a variety of disciplines is that what we think we see is only the tip of the iceberg of what the brain sees. In particular, there is strong evidence, documented here in several chapters, that visual information used for action is largely processed without being consciously monitored. Patients suffering from “blindsight,” for example, can notoriously grasp an object which they swear they do not see (L. Weiskrantz is a pioneer in the field). The paradox here, however, is that when you begin to study perceptual consciousness you end up learning a lot about what is non-conscious or “implicit,” and at the end of the section on vision the reader may well wonder what perceptual consciousness was in the first place.

Does consciousness have “neural correlates”? Well, the question only makes sense if you are ready to assume that consciousness is “some-thing” separate from the brain, which is by no means granted. In any event, in the section devoted to the issue there are two excellent chapters on experimental research about hallucinogen-induced states and the obsessive-compulsive disorder. The latter, by J. Schwartz, interestingly takes on the philosophers, but ends up proposing a “new” concept of “mental force,” which unfortunately is but the good old free will of St Augustine and many others.

The chapters on emotion (not adjacent to the last section) are also written by leading neurophysiologists and highly technical; the ordinary reader may find them intimidating. They also present, without much warning, three very different approaches to emotion and consciousness. Kaszniak and colleagues describe their research on the possible cerebral location of conscious emotional arousal, and interestingly confirm other recent results by different researchers, which point to the anterior cingulate cortex. Watt, instead, engages in the ambitious task of arguing that all conscious mentality is rooted in emotional/evaluative operations of the thalamus and the midbrain. Panksepp and Burgdorf, finally, explore vocalizations of rats as a clue to animal “joy,” but in the obvious absence of verbal reports it is difficult to see what this can tell us about emotional consciousness.

The chapters on timing are also good and highly technical. They address the well-known problem, first raised by neurosurgeon B. Libet, of paradoxical time differences between brain activation and conscious experience of a stimulus. And when apparent time reversals are the issue, the attraction of counterintuitive subatomic physical theory becomes, for some researchers, irresistible. Whether quantum mechanics, or quantum field theory, or “quantum monadology” (see the relatively reader-friendly chapter by K. Yasue) should be used to explain consciousness is a very controversial issue today. All the contributors on this topic are supporters of this line of inquiry.

To the question, Why are some animals (us for example) conscious?, most researchers today would answer that this trait was naturally selected because it is adaptive, namely, it furthers survival. The question then becomes, how did this evolution occur? N. Humphrey, R. Gregory, and A. Cairn-Smith address the emergence of awareness of sensory stimulation (“qualia”), though not quite convincingly – there is no “me” in lower animals. A welcome surprise is a chapter by archaeologist S. Mithen, on the evidence for conscious motor activity gathered from tools made as early as 1.4 million years ago. But Darwinism can also be employed for research on the conscious brain here and now. In a short and lucid chapter, W. Calvin illustrates his hypothesis: sensations, ideas, and purposes would spread like new traits in populations of cortical cells, which would then compete for survival, i.e. for awareness, in the flowing stream of consciousness.

Readers who are weary of incessant references to the brain may perhaps find solace in the last and longest section of the collection, devoted to phenomenology. The latter is the name both of the totality of conscious subjective experiences, and of a Continental philosophical school which had its heyday in the first half of the twentieth century. The authors also and often make reference to Eastern philosophies in the attempt to integrate the allegedly limited approach of Western science. But it is hard to read these chapters without wondering if the most important contribution of the phenomenological approach to the study of consciousness might reduce to its negative claim that subjectivity cannot be captured by objective science. Phenomenology never explains consciousness, because it is introspective consciousness. So it is not surprising to find an inconsequential chapter on science, phenomenology, and the Tibetan Buddhist Dzog Chen (Hut); a proposal to explore the second-person perspective on consciousness (de Quincey) — as if object-relations theory had not done exactly that for the last fifty years; or a resuscitation of Bishop Berkeley’s untenable idea that physical science is about subjective experience anyway (Zajonc). Yet there is a thread in the maze of these speculations, and it finally emerges where Frances Vaughan brings back the soul (sic) from the Kingdom of the Dead, and makes it stand next to mind and body in the trinity of being. This is an ultra-Cartesian trialism which will make old-fashioned dualists blush for their lack of imagination. The sober reader will wonder what this has to do with the science of consciousness, anyway.

When all is said and done, one hopes that the editors of a predictable new collection, from the fourth Tucson conference scheduled to take place in April, 2000, will do a better job. At the very least, if the history of philosophy is not their main interest they should stay away from it. It is disturbing to read that Socrates had the cerebrum in mind while for Democritus mental processes were fundamental constituents of reality (p. xix), since exactly the opposite is true. And it is also true that Gottfried Leibnitz (1646-1716) was active between the seventeenth and eighteenth century, not in the nineteenth (p. 310). Old Hegel may have had strange ideas indeed, but at least he knew his history all right.

Categories: Philosophical, General