“Daniel C. Dennett, the director of the Center for Cognitive Studies at Tufts University, is one of a handful of philosophers who feel this quest [to explain consciousness] is so important that they have become as conversant in psychology, neuroscience and computer science as they are in philosophy. “Consciousness Explained” is his attempt, as audacious as its title, to come up with a scientific explanation for that feeling, sometimes painful, sometimes exhilarating, of being alive and aware, the object of one’s own deliberations.
“Ever since Emil Du Bois-Reymond demonstrated in 1843 that electricity and not some supernatural life force travels through the nervous system, scientists have tried to explain mental life biologically. It’s been a long, slow haul. An important step was taken in the early 1940’s when the neurologist-philosopher Warren McCulloch and the teen-age prodigy Walter Pitts showed how webs of neurons exchanging electrical signals could work like little computers, picking out patterns from the confusion buzzing at our senses. Inspired by this metaphor, neuroscientists have been making the case that memories are laid when the brain forms new connections, linking up patterns of neurons that stand for things in the outside world.
“But who, or what, is reading these neurological archives? The self? The ego? The soul? For want of a theory of consciousness, it is easy to fall back on the image of a little person — a homunculus, the philosophers call it — who sits in the cranial control room monitoring a console of gauges and pulling the right strings. But then, of course, we’re stuck with explaining the inner workings of this engineer-marionette. Does it too have a little creature inside it? If so, we fall into an infinite regress, with homunculi embedded in homunculi like an image ricocheting between mirrors.
“The great success of cognitive science has been to point a way out of this fun house. As Mr. Dennett explained in an essay in his 1978 book, “Brainstorms,” the reason we get the regress is that at each level we are assuming a single homunculus with powers and abilities equal to those of its host. Suppose instead that there are in the brain a horde of very stupid homunculi, each utterly dependent on the others. Make the homunculi stupid enough and it’s easy to imagine that each can be replaced by a machine — a circuit made of neurons. But from the collective behavior of all these neurological devices, consciousness emerges — a qualitative leap no more magical than the one that occurs when wetness arises from the jostling of hydrogen and oxygen atoms.
“The information processing carried out by the homuncular hordes need not be a particularly orderly affair. In the late 1950’s a computer scientist from the Massachusetts Institute of Technology named Oliver Selfridge unveiled a model called Pandemonium, in which homunculi — he called them demons — shouted at one another like delegates in a very democratic parliament, until they reached a consensus on what was going on outside the cranial chamber. In a more recent theory, called the Society of Mind, Selfridge’s colleagues Marvin Minsky and Seymour Papert call these homunculi agents. The psychologist Robert Ornstein calls them simpletons, perhaps the most appropriate name of all.
“Some homunculi might be dedicated to such basic tasks as detecting horizontal and vertical lines, or identifying phonemes. Their reports would be monitored by other homunculi (shape recognizers, word recognizers) that are monitored by still other homunculi. Suppose you are watching a play. Tripped by reports from various line and shape detectors, the homunculus that recognizes bilateral symmetry might fire, and its signals (along with those of other homunculi) would activate the person detector. There is someone on stage. But before that final flash, other parts of the brain might be entertaining rival hypotheses — what Mr. Dennett calls multiple drafts. Spinning tops and pine trees can also appear bilaterally symmetrical. But the minority committees of homunculi considering these interpretations would be contradicted by reports from various motion detectors (trees don’t move, people don’t spin) and finally by the sighting of moving columns generally agreed by yet other homunculi to be arms and legs.
“Considering all this hubbub, maybe it’s a blessing that we are not more conscious than we are. Usually it is only the winning interpretations that we become aware of. But occasionally we get to eavesdrop on the behind-the-scenes debate. Sometimes in winter, I glance out the back window of my apartment in Brooklyn and am startled to see an old Indian woman in a shawl, like a figure from an R. C. Gorman painting, standing on the terrace of the building behind mine, huddled against the wind. It takes a second longer before a rival, more convoluted interpretation emerges: the shape is really a tree wrapped in burlap to protect it until spring. Sometimes, driving fast with the window down, you might find your word detectors, fed by your phoneme detectors, misfiring, picking voices out of the wind.
“But what exactly is happening when these subliminal judgments shove their way into consciousness? As Mr. Dennett explains, if the result of all the homuncular discussion is that a winning interpretation is presented for appreciation by some central self, then we have solved nothing. We’re back to the image of an intelligent, fully conscious homunculus sitting in a control room, which Mr. Dennett calls the Cartesian Theater.
“His way out of this mess is to propose what he calls a Joycean machine, a kind of mental operating system (like the computer programs Windows or MS-DOS) that acts as a controller, filtering the cacophony of inner voices into a silent narrative — a stream of consciousness. To avoid the problem of infinite regress, he hypothesizes that this master controller is not a fully cognizant marionette but a “virtual machine,” created on the fly from temporary coalitions of stupid homunculi. It is because of this mental software, he proposes, that we can not only think but reflect on our own thinking, as we engage in the step-by-step deliberations that occupy us when we are most aware of the plodding of our minds.
“For someone who is encountering this kind of theory for the first time, that is probably not a very convincing summary. But Mr. Dennett’s argument is not easily compressible. At a time when so many nonfiction books are just horribly long magazine articles, he makes use of just about every one of his 500 pages. As he readily concedes, it is practically impossible — for him or anyone else — to keep from lapsing into a deeply grooved mental habit: thinking that there is some kind of ego inside us, peering out through the ocular peepholes. To break us of these assumptions, he makes his argument cumulatively, using thought experiments and anecdotes to build up his case piece by piece. For 50 pages or so, he attacks his subject from one angle, until we start to get a glimmer of what he means. Then he retreats and attacks from another angle.
“In his best seller, “The Emperor’s New Mind,” the Oxford mathematician Roger Penrose dismissed in a few pages the possibility that consciousness can be explained by thinking of the brain as a kind of computer. If there is any justice, everyone who bought a copy of Mr. Penrose’s far more difficult book will buy a copy of Mr. Dennett’s and marvel at how, in the hands of a master explicator, the richness and power of the computer metaphor of the mind comes shining through. A JOYFUL KILLER OF SACRED COWS”
So this is where philosophy is these days: helping scientists out who’ve got themselves into an awful conceptual muddle. Dennett admits, in one of the book’s appendices, that all he’s been doing his whole career is taking the lesson he learnt from Wittgenstein – to which most of his contemporaries were virulently resistant – and he “put it to work”. And that’s how this book works – he’s tackling the big messy metaphors that have beset neuroscience – and the other sciences of the mind – as well as all the other common sense ways of thinking that have bedeviled this particular branch of science – and turning them inside out and giving the reader’s thinking – as well as that of the scientists themselves – a thorough good seeing to. Thanks Mr Dennett.
This is a good introduction to the philosophy of mind, though I imagine there are better ones – more accessible and less of a slog. But any more than that? I’m not sure what Dennett achieves in the end, or indeed what any branch of philosophy can – other than clearing the way for the scientists to come in with their big cumbersome microscopes and their computers that beat Grand Masters. I suppose he does point the way for the philosophy and science of consciousness, but for all that he might just as easily be guilty of muddy thinking as those he throws mud at. Though it’s a pretty convincing narrative. And maybe he will paint the picture that will shape, for good or ill, the way we think of consciousness for the next few years of our scrabbling about.