Consciousness Explained

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Last Updated on May 7, 2015, by eNotes Editorial. Word Count: 1884

Philosopher Daniel Dennett takes as his purpose in Consciousness Explained the task of characterizing consciousness in terms of physical events in the brain that are not conscious. This, Dennett admits, is counterintuitive, for though consciousness may well be “supported by” or “connected to” the brain, consciousness itself seems fundamentally distinct...

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Philosopher Daniel Dennett takes as his purpose in Consciousness Explained the task of characterizing consciousness in terms of physical events in the brain that are not conscious. This, Dennett admits, is counterintuitive, for though consciousness may well be “supported by” or “connected to” the brain, consciousness itself seems fundamentally distinct from (mere) physical processes. How those processes actually can be one’s sensation of intense grief or one’s experience of a too-sour orange is the burden of his exposition. Part of the difficulty Dennett faces is in overcoming the heritage of René Descartes (1596-1650), whose Meditations (1641) helped establish in popular sentiment the notion of the dualism of mind and body. For Descartes, mind was a kind of “stuff” altogether different from physical matter but every bit as real. The brain could be studied empirically because it was subject to physical laws, but mind by definition was outside the reach of the physical sciences. The difference between the content of one’s conscious experience, the sense of what it is like to be oneself, and the firing of synapses in the brain seemed absolute. Dennett rejects Cartesian dualism in part because of its difficulty of explaining coherently how a nonphysical mind could affect, and in turn be affected by, a physical body, but also because dualism is resistant to empirical investigation.

Such investigation must be from the “third-person” point of view, he says, and so the “data” of one’s inner experience must be made publicly available in a way that does not already presume a particular theory of the mind. In the first part of Consciousness Explained Dennett develops a method (he dubs it heterophenomenology) by which a subject’s description of the phenomena of his or her “inner life” (the intentionality or “aboutness” of conscious experience) becomes a text which in effect constitutes a kind of fictional world—fictional because the subject can only report what it seems like, say to make an important decision, not what is actually going on inside the person: that actuality is unavailable to introspection but is the proper study of the empirical theorist. This distinction is crucial to Dennett’s own theory, which he develops in the second section of the book.

Dennett calls his model of consciousness the Multiple Drafts theory, arguing that “all varieties of perception—indeed, all varieties of thought or mental activity—are accomplished in the brain by parallel, multitrack processes of interpretation and elaboration of sensory inputs. Information entering the nervous system is under continuous ‘editorial revision.’” There is no single spot in the brain where consciousness “happens”; once one part of the brain has made a certain discrimination (of movement, say, or color), that information is an available part of the eventual pastiche that is conscious experience.

Dennett is not content with banishing dualism; he is also determined to root out from prevailing materialist theories of the brain any notion of a “Cartesian Theater,” a central location where the brain must re-present each of its discriminations. That is false, says Dennett, for such a notion would require a further explanation of how the “audience” in the Theater—called a “homunculus” or “little person” by philosophers—was itself conscious of the events on display. If the “explanation” involved positing another “theater” in the brain of the homunculus, and so on, clearly the question of the nature of consciousness would simply be forever deferred. According to Dennett, this brand of materialism is no better than Cartesian dualism; and though few if any cognitive scientists and philosophers would call themselves Cartesian materialists, the author is convinced the influence of Descartes continues to muddy the theoretical waters.

Perhaps the most appropriate metaphor for Dennett’s Multiple Drafts theory is that of a word processor. Any computer hardware running a particular word processing program in effect becomes a “virtual machine” for that program, responding as if the hardware had been designed just for running that program. Diverse computers—even large parallel processing units—that run the same program become the same virtual machine. The word processing program may seem relatively straightforward, with one event happening after another in serial order, but “in reality” many calculations are coming from various subsystems of the computer to be integrated into the program’s handling of the data. Dennett suggests that since the brain is a parallel processing unit, its so-called “stream of consciousness” might well be reproducible on any other such computer system. But beware: “the Multiple Drafts model avoids the tempting mistake of supposing that there must be a single narrative (the ‘final’ or ‘published’ draft, you might say) that is canonical—that is the actual stream of consciousness of the subject, whether or not the experimenter (or even the subject) can gain access to it.” Just as many calculations all over the computer are required to make a word processing program show the contents of the open file, so deep in the brain a kind of pandemonium reigns:

In our brains there is a cobbled-together collection of specialist brain circuits, which, thanks to a family of habits inculcated partly by culture and partly by individual self- exploration, conspire together to produce a more or less orderly, more or less effective, more or less well-designed virtual machine.… Who’s in charge? First one coalition and then another, shifting in ways that are not chaotic thanks to good meta-habits that tend to entrain coherent, purposeful sequences rather than an interminable helter-skelter power grab.

The specialist brain circuits, says Dennett, are the products of Darwinian evolution; that process works slowly in the medium of genetic variation, he says, but when genetic variation produced organisms capable of wide-ranging adaptation, this “phenotypic plasticity” produced greater variations. With the development of human society there came a new and even more rapid kind of variation—cultural evolution. Borrowing a term from contemporary evolutionist Richard Dawkins, Dennett traces the functioning of what Dawkins calls “memes” in the development of human culture. Memes are defined as complex ideas (such as the idea of revolution or the idea of clothing or the ideas of truth and beauty)which take up residence in the brain, duplicating themselves by language and ensuring their survival through the establishment of particular cultural expressions; as Dennett puts it, “A scholar is just a library’s way of making another library.” The infestation of human brains with memes is central to Dennett’s view of the nature of consciousness:

Human consciousness is itself a huge complex of memes (or more exactly, meme-effects in brains) that can best be understood as the operation of a…virtual machine implemented in the parallel architecture of a brain that was not designed for any such activities. The powers of this virtual machine vastly enhance the underlying powers of the organic hardware on which it runs, but at the same time many of its most curious features, and especially its limitations, can be explained as the byproducts of the kludges…the computer hacker’s term for the ad hoc jury-rigs that are usually patched onto software in the course of debugging to get the stuff actually to work.

Consciousness is not a seamless fabric; it has deficiencies and gaps that the organism learns to work around. For example, human beings talk to themselves because one specialized discriminator in the brain needs to communicate with another; language creates a “virtual wire.” In another example, Dennett describes a person walking into a room who sees on the wallpaper hundreds of identical designs. The person almost instantly recognizes that all the designs are the same but that does not mean each instance of the design is stored as an image in the brain; it would be physically impossible for the eye to take in all of the instances, and (since there is no Cartesian Theater) no “place” where all the images are interpreted. What happens, says Dennett, is that the brain makes the assumption that the images are the same and represents that fact. The result is as if the person had “seen” all of the designs, but that is not the case. To take another example, the brain can represent a certain time sequence in a different order from that of a given set of inputs. One might get in one’s car and put on a hat; but later, as the multiple drafts of “the experience” are vying for attention, one’s brain may represent a different temporal order: one remembers putting on a hat and then entering one’s car. A person “feels” that the latter is the “way it happened.”

The self, says Dennett, is an abstraction analogous to the mathematical “center of gravity.” The stories humans tell about themselves (and to themselves) constitute the abstraction Dennett calls the “center of narrative gravity.” These stories constitute an “as if” unity of the self, just as the word processing program seems unified even though many calculations seemingly unrelated to the processing of words are occurring at each moment. Consciousness is a virtual machine, a program running on a complex parallel processing system; the representations of the various subsystem discriminators just are the conscious “feel” of the color yellow or sense of regret over a road not taken.

Dennett, director of the Center for Cognitive Studies at Tufts University, is a teleological functionalist, one who strives to take seriously the “aboutness” (the intentionality) of consciousness and one who recognizes the interests and purposes of organisms (or the memes inhabiting them), but one who believes that there is nothing unique to consciousness “over and above” the functioning of the brain’s subsystems. His theory asks the reader to agree that the brain can produce a “representation of presence” without there being a “presence of representation” (that is, images in the head) and that that is what one experiences when one consciously experiences the presence of another.

Dennett’s critics have charged him with explaining away the “specialness” of consciousness and with using images such as “the editing of multiple drafts” that are simply too vague or that mask the ways consciousness functions that are not computer- like. In the third section of his book (and in its two appendices for philosophers and scientists) he attempts to respond to some of the difficulties of his theory. He uses what he calls the “systems reply” in suggesting that while admittedly no subsection of the brain is conscious, taken as a complex system consciousness is what “seems” heterophenomenologically to occur. His picture of the decentered self constituted by language bears a remarkable resemblance to the view of the self put forth by certain literary theories, most notably Deconstruction, and a theory of the mind that draws too heavily on contemporary metaphors may soon find itself irrelevant. Yet Dennett’s overview of the literature of cognitive science and philosophy provides a rich introduction to some of the most creative responses to the ancient question of “who (or what) am I?”

Sources for Further Study

Booklist. LXXXVIII, October 1, 1991, p. 222.

Boston Globe. November 3, 1991, p. 94.

Kirkus Reviews. LIX, September 15, 1991, p. 1194.

London Review of Books. XIII, November 21, 1991, p. 3.

Los Angeles Times Book Review. November 24, 1991, p. 6.

The New Republic. CCV, December 23, 1991, p. 40.

The New York Times Book Review. XCVI, November 10, 1991, p. 1.

Publishers Weekly. CCXXXVIII, August 16, 1991, p. 41.

Science News. CXL, December 14, 1991, p. 395.

The Wall Street Journal. November 7, 1991, p. A12.

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