NONFICTION - Nov. 24, 1991

CONSCIOUSNESS EXPLAINED by Daniel C. Dennett (Little Brown: $27.95; 492 pp.). In an age when glib, supposedly catch-all theories are as common in academe as waiters with screenplays are in Hollywood, one is inclined to find the title chosen by Daniel Dennett, an arts and science professor at Tufts University, more than a bit off-putting. Dennett makes up for this bit of hubris, however, through clear, intellectually forceful theories, a hearty sense of humor and the humble if belated admission in his conclusion that “my explanation of consciousness is far from complete.”

In Freud’s day, “consciousness” was explained with relative ease: It was a thought process (the ego) that mediated between social directives (the superego) and biological drives (the id). But in subsequent decades, cognitive theorists scorned this notion for its most unscientific implication that a soul or little man (a homunculus) is hiding somewhere in our brain. In its place, Dennett offers a synthesis of their currently favored theories, which he dubs a “multiple-drafts model of consciousness.” There is no little man, no ego, no “I” coordinating our thoughts like some benevolent dictator, this theory holds. Rather, consciousness is a fluid process, a Joycean stream wherein one set of neurons, recognizing a particular pattern of shapes, events or other sensations, responds by activating another group of neurons, thus creating the silent narratives we call feelings and ideas .

This theory is likely to damage the wall we have erected between humans and “lower animals” as much as Charles Darwin’s “On the Origin of Species.” What most separates us from them, we have long maintained, is that we alone possess a stable sense of “self” to guide us, even though we may lose sight of it on occasion. Delicately and compassionately, Dennett suggests that this spiritual entity may be pure fancy. “So wonderful is the organization of a termite colony that it seemed to some observers that each termite colony had to have a soul,” he writes. “We now understand that its organization is simply the result of a million semi-independent little agents, each itself an automaton, doing its own thing.”