OR, WHERE YO HEAD AT
Cognitive philosopher Daniel Dennett's term for the popular concept of a single locus in the brain where input terminates and output originates.
An idea of a dual, distinct nature of the mind and body respectively has always been held as one of many concepts central to Cartesian philosophy. Descartes himself explained it thus: "I am not that concatenation of members we call the human body. Neither am I some subtle air infused into these members. . .for I have supposed these things to be nothing. . .nevertheless, I am something."(1) Cartesian dualism was supported by philosophical thought for much of history, until the fairly recent ascendance of a materialist view of the human mind (or at least the components from which it proceeds) within the nervous system. However, the transfer of the essence of "Mind" into some physical form has not necessarily meant initiation of a radical re-evaluation of the singular nature of the mind. Daniel Dennett’s Consciousness Explained, among other contemporary works in cognitive studies, has attempted that re-evaluation – pointing out the fallacy in unknowingly maintaining a "Cartesian materialism" where a single ego is sacrosanct in understanding consciousness, and proposing alternatives to such.
The original problem of Descartes’ theory of a non-material mind that drives the material body is that of Descartes’ anti-materialist interactionism. Because nothing in the brain could be the res cogitans, the thinking thing capable of considering "a mind", Descartes believed that the mind had to be fully non-material (as Dennett points out, the statement "I have a brain" seems thoroughly uncontroversial).(2) However, if a non-material object is to affect something material (like the brain), it must do so in a physical fashion in order to preserve a coherent worldly physics (where any change in an object’s trajectory must be accomplished by energy expenditure). The nonscientific, fantastic nature of interactionism is presented by Dennett through excerpting a section of the comic "Casper the Friendly Ghost" where the spirituous main character grabs a falling object, only to become safely insubstantial to avoid another. Many philosophers and non-philosophers alike thoroughly eschew interactionism, and would vehemently deny that their understanding of the mind reflects that of Descartes – and yet such a reflection remains pervasive, simply for a lack of inspection.
One of our most fundamental ideas of a conscious mind is that it cannot be separated from a point of view – a point from which input can be considered (as in a physics problem), and from which output can proceed. But is there an actual point within an individual that can be considered a "point of view"? Descartes presented a "superficially natural and appealing"(3) idea: that of the pineal gland, a tiny section of the brain that acted as the soul’s pilot seat and conducted consciousness – and modern philosophy of the consciousness has often posited such a "finish line" in the brain, at which "not observed" and "observed" can be separated. This idea of a centered locus in the brain for the mind’s "point of view" is called by Dennett "Cartesian materialism". After all, we know that input and output can be charted to a certain extent – when nerves in a finger send impulses to the brain due to heat, or when other nerves send impulses back that move that finger away. Shouldn’t those "lines in" and "lines out" rationally imply a single common endpoint by the rules of geometry, like the progression of Descartes’s own doubt to "cogito ergo sum"? No, in fact – not anymore than two ends of a single curve in a Cartesian plane must imply that the curve is parabolic.(4) Input needn’t "terminate" at a single point, any more than output must "initiate" there. Thus concludes the idea of a necessary and axiomatic "unity of consciousness".
Dennett traces some difficult problems within philosophical ideas of consciousness (qualia, artificial intelligence, self-representation) to the prevalence of Cartesian materialism, and proposes a workable alternative that may hold key answers: his "Multiple Draft Model" where perception and thought are accomplished by "parallel, multitrack processes of interpretation and elaboration of sensory inputs."(5) A series of parallel processes edit the information received by the nervous system and produce output that is assembled by other, overlapping processes into coherent action; one part of the brain may not yet have "received" one aspect of input before another part "produces" one aspect of total output. The process is comparable to a multi-version academic paper in constant review and revision by a series of peers that nevertheless has a coherent, constant, and seemingly completely linear approach to a topic. Much of Consciousness Explained is devoted to the application and defense of this concept, but Dennett makes it clear that this is merely one of many possible, and nonobvious, approaches to the mind that truly consider the difficulty presented by Descartes’s singular ego.
The concept of Cartesian materialism, and its centrality, show above all else Descartes’s large influence on philosophical understanding of the mind, and something of an inability to challenge his convictions – they do, after all, seem to flow naturally from the conscious experience of individuals. Dennett acknowledges the difficulty of the Multiple Drafts model: its non-obvious nature compared to a simple correlation of "I" with a real and identifiable location (and the comfort that Descartes’s separation of mind and body affords to an individual’s self image). However, if neuroscience and other aspects of a material consideration of consciousness are to bring their information to bear in a philosophical conversation on the topic, the reign of this idea must be toppled. Descartes will not be demolished – but he cannot be above criticism.
, p. 65.
2. Dennett, p. 29.
3. Ibid., p. 35.
4. Ibid., p. 109.
Dennett, Daniel. Consciousness Explained. Boston: Little, Brown and Company, 1991.
Descartes, Rene. Discourse on Method and Meditations on First Philosophy. 1637 and 1641. Trans. Donald A. Cress. Cambridge: Hackett, 1998.