Consciousness is hard to miss but easy to avoid, theoretically speaking. Nothing could be more present to you than your current state of consciousness—all those vivid sensations, pressing thoughts, indomitable urges. But it has proved only too easy for theorists of mind to turn a blind eye to what gives them a sense of sight to start with. Thus for most of the century consciousness has been comparable to sex in Victorian England: everyone knew it was there, throbbing away, but it was not a fit subject for polite conversation, or candid investigation. With the rise of behaviorism, in both philosophy and psychology, consciousness was deemed the “ghost in the machine,” an ethereal legacy of Cartesianism that could be neither observed nor measured, a purely private realm of no conceivable relevance to objective science.
Neither did neurophysiologists find it necessary to recognize the scientific legitimacy of consciousness: they did just fine by regarding the brain as a wholly physical system, a complex of neurons and their biochemistry. Even the nascent computer-based theories of the mind had no place for consciousness, since computers can perform their information-processing operations without benefit of conscious awareness. Consciousness seemed like a phenomenon it was not necessary to consider, and hence possible to deny—common sense notwithstanding. Other subjects took up the intellectual space that one might have thought would be occupied by consciousness: overt physical behavior, environmental “stimuli,” internal states of the nervous system, abstract computations. In principle, as they have defined “principle,” the sciences of human nature need make no reference to consciousness and suffer no explanatory or predictive inadequacy.
Yet to any sensible person consciousness is the essence of mind: to have a mind precisely is to endure or enjoy conscious states—inner, subjective awareness. Recently consciousness has leaped naked from the closet, streaking across the intellectual landscape. People are conscious—all of them! The deep, dark secret is out. Even animals carry their own distinctive quantum of consciousness, their own inner life.You can almost hear the sigh of relief across the learned world as theorists let loose and openly acknowledge what they have repressed for so long. The Nineties are to consciousness what the Sixties were to sex.
Why this has occurred is somewhat obscure, as intellectual revolutions often are. Post-positivist disenchantment with behavioristic and materialistic reductionism began to grow in the Seventies, abetted by a greater willingness to return to the deep old problems of philosophy. Philosophers became less ready to assume that a recalcitrant philosophical problem could be diagnosed as mere conceptual confusion, as a pseudoquestion. At the same time neuroscientists began trying to build connections from the neural to the mental, acknowledging that the brain is nothing if not the seat of the mind. It was only a matter of time until they faced up to the fact that the brain is also the organ of conscious awareness. Instead of shunning consciousness as prescientific, maybe it could be approached as the holy grail of brain science, from …