Book: CONSCIOUSNESS: A USER'S GUIDE
Author: Adam Zeman
Price: Yale University Press, ?18.95
St Augustine was perplexed by the nature of time: "If no one asks me, I know what it is. If I wish to explain it to him who asks me, I do not know." Anyone who has paused to reflect on the nature of consciousness will know the feeling.
If you favour life over death, enjoy warm summer evenings and the taste of chocolate, recoil from the smell of shit and opt for anaesthesia when having a tooth extracted, then you intuit the meaning of consciousness well enough. It is a defining feature of personal existence, the surest thing: "I think, therefore I am." But lift the veil of this intuition and you see that consciousness is not the simple creature we imagine. It is a chimera, a fire-breathing monster with the head of a lion, the body of a goat, and a serpent's tail. Gangs of neuroscientists and philosophers are now stalking this beast, equipped with brain scanners and the conceptual paraphernalia of neuropsychology and cognitive science. They expect to tame the brute and solve the problem of consciousness. Others say it is a fool's errand.
Adam Zeman is something of a chimera himself-a practising neurologist well schooled in psychology and philosophy. As such he is a rare animal, on these shores at least. At school, he says, he managed to escape the British tendency of keeping science and literature in sealed compartments "...reading Shakespeare in the morning and Newton in the afternoon, so to speak." His eclecticism shines through this grand tour of the expanding empire of consciousness studies.
The problem of consciousness is essentially this: how can the mental be reconciled with the physical? How does the flowing pageant of awareness that fills our waking (and dreaming) lives emerge from the soggy substance of the brain? I have already played a sleight of hand, juxtaposing the "how can" with the "how does." Some students of consciousness don't recognise the distinction; they believe that "how can" is subsumed under "how does"; that consciousness and brain activity are one and the same thing; that if you explain the working brain, you have explained consciousness.
The "how can/how does" distinction corresponds to the philosopher David Chalmers's contrast between the "hard problem" and "easy problem" of consciousness. The easy problems are the bread and butter of neuroscience, the objective study of brain and mind: what are the causal relations between different psychological states? To what extent are various psychological functions (perception, memory, language and so on) distributed across different brain systems? How are cognitive processes implemented at the neuronal level? Note that these questions are "easy" in the same way that the problems of cosmology or particle physics are easy; that is, not very easy at all. The point is they are transparent to scientific scrutiny.
But how are we to account for phenomenal consciousness-awareness from the inside, as opposed to external observations of brain and behaviour? Is the redness of a red balloon something more than the neuronal response of eye and brain to electromagnetic radiation of wavelength 740 nanometres? Or take the example of pain. We can analyse pain biologically and behaviourally as a state that is caused by bodily damage, and which predisposes the individual to avoid further damage. Beyond this we can investigate how pain is realised in the nervous system in terms of the activation of A-fibre and C-fibre pathways. But there is nothing in this third-person narrative about the feelings involved. This is the "hard problem." It is hard precisely because of the shift from an objective to a subjective view. Objective science can tell us about the functions of pain and the associated patterns of neurophysiological activity, but still it seems reasonable to ask, why does it hurt? Experiences of redness or pain seem to be intrinsically, irreducibly, subjective.
Zeman surveys the scene on both sides of the divide. He begins with an analysis of the term "consciousness" itself, its history and current usage. In one, mundane, sense it means no more than "wakefulness." To be conscious is to be alert, vigilant and lucid; it is a matter of degree. It is the other main everyday use of the term-"conscious" as "aware of" -that takes us into the hard territory. To say that someone is conscious in this sense is to impute experience. As Zeman puts it, "We imply that there is 'something it feels like to be' this person at this very moment, in a sense in which there is nothing it feels like to be a stone, or to be lost in a dreamless sleep."
Zeman then turns to consider the other side of the mind-body equation: the structure and functions of the nervous system. No one doubts that the brain is the organ of mind. If we can crack its codes, perhaps the mystery of consciousness itself will melt away. Successive chapters analyse features of the brain that create the capacity for consciousness, and those that deliver the experiential goods in terms of the content of consciousness. In other words, our experiences arise through various modes of sensation and thought (content), all of which require certain basic preconditions of alertness and arousal (capacity). Brain disorder, as Zeman vividly illustrates, can affect both dimensions. The final chapters return to speculation and philosophy, taking in, among other things, the evolutionary significance of consciousness, animal minds, artificial intelligence and the sentience of advanced extraterrestrials.
Some philosophers, dismissed by others as "mysterians," believe that the problem of consciousness is insoluble, or at least that we feeble-minded humans are incapable of finding a solution. It exceeds our mental capacity, they say, in the way that algebra or the concept of justice are beyond the intellectual scope of a Shetland pony. The problem of consciousness might, in fact, be a misconception of science. What makes science strong as a means of understanding the outer, material world-objective, third-person observation-is precisely what makes it ineffectual when it comes to understanding the "inner world" of consciousness. Robert Frost said, "Poetry is what is lost in translation." Likewise, consciousness is lost in translating from first-person experience to third-person description of brain states.
Accounts of consciousness may be the true province of art rather than science. The novelist and critic David Lodge offers some valuable insights concerning the representation of consciousness in literature in his collection of essays Consciousness and the Novel. Works of literature (in contradistinction to science) describe "the dense specificity of personal experience." Science tries to formulate universally applicable, general explanations. The subjective and the uniquely particular are anathema to science. Lodge suggests that "Lyric poetry is arguably man's most successful effort to describe qualia (the raw feels of experience). The novel is arguably man's most successful effort to describe the experience of individual human beings moving through space and time."
Zeman is aware of the art/science dichotomy. Right at the outset he remarks, "The mounting eruption of interest in consciousness flows from a fault line in human thought," a rift, he says, which "runs, roughly speaking, between the sciences and the arts."
So, how does meat become mind? By what alchemy does matter turn into imagination? Zeman offers no solution to the riddle of consciousness but, by the end of his epic quest, we have that chimerical beast more clearly in our sights and, by now, it looks real enough. Science is going to capture and dissect it before very long-that is, unless it first devours science.
Zeman is a humane and engaging writer and this is a wonderfully ambitious and entertaining book. I can think of no better guide to "the last great frontier of science."
