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Chapter 17: The Unity of Consciousness

"[I] s not the conclusion of the whole matter this? -- that the soul is in the very likeness of the divine, and immortal, and intelligible, and uniform, and indissoluble, and unchangeable; and the body is in the very likeness of the human, and mortal, and unintelligible, and multiform, and dissoluble, and changeable. ... But if this is true, then is not the body liable to speedy dissolution? and is not the soul almost or altogether indissoluble? (Plato: Phaedo)
I cannot distinguish in myself any parts but apprehend myself to be clearly one and entire." (Descartes)
"The consciousness, which is itself and integral thing not made of parts, 'corresponds' to the entire activity of the brain, whatever that may be, at the moment." (James)

on the brain side "we see nothing but complexity and diversity" -- it's a welter of things happening everywhere everywhen

At any single time "your visual system is ... dealing with color, motion and other feature in different visual areas. At the same time processing is going on in other sensory area, in memory systems and in emotional system. Thoughts, are bubbling along, movements are being planned and coordinated and sentences are being constructed." (242)

"Dualists believe that consciousness is intrinsically unitary, each person having their own single consciousness that is quite different from their physical brain." (243)
Popper and Eccles: "the unity of conscious experience is provided by the self-conscious mind and not by the neural machinery of the liaison areas f othe cerebral hemisphere. (1977: 362)
"A far more constructive approach is t try t find ut how the brain carries ut the integrating and unifying functions." (244)

"A third, and final, approach is to try to find out how the brain carries out these integrating and unifying functions." (244)

How is visual experience unified?
"your visual system is ... dealing with color, motion and their features in different visual areas."
yet, when you view a flipping coin "bits don't fly off. The silver color doesn't depart from the shape, and the shape doesn't lag behind the motion."
The more general binding problem in cognitive science concerns how conjunctions of properties are represented, ranging from the binding of shape and color in detecting blue triangles or red squares, to the binding of words and phrases to their roles in sentences.
"There are obviously close relationships between attention, consciousness, and binding, but just what sort of relationships is not yet clear." (246)

studies of cats' visual systems show "oscillations in the range f 35-75 hertz (i.e., 35-75 cycles per second), in which large numbers of neurons all fired in synchrony with one another. "
Christof von der Malsburg suggests "that this coordinated firing might be the basis of visual binding"
Crick & Koch go further, suggesting, "this synchronized firing on, or near, the beat of a gamma oscillation (in the 35- to 75-Hertz range) might be the neural correlate of visual awareness" (Crick 1994: 252)
Other theories allow "for many kinds of synchronized neural activity apart from that based on oscillations." (247)

"although they explain how selected information is held together to provide unified percepts, we may still wonder whether this accounts for subjectivity"
they say things that suggest they're committed to "Cartesian materialism"

Zeki's view: "a multiplicity of consciousnesses is the norm; the unification that comes with self consciousness is an exception that is only possible through language." (249)

"Multisensory integration makes possible a world in which objects can be recognized as the same thing, whether they are touched, seen, tasted or heard." (251)

evidence: computer simulations "revealed how reentry can solve the binding problem by coupling neuronal responses of distributed cortical areas to achieve synchronization and global coherence." (20001: 119)

depends on renentrant connections between language and conceptual systems
"these allow for the construction of a 'dynamic core'" which "can involve completely different brain areas, leaving others still active but not part of the core."

Humphrey: "These selves have come to belong together as one Self that I am because they are engaged in one and the same enterprise: the enterprise of steering me ... through the physical and social world ... my selves have become conscious through collaboration. (2002: 12)
Hard Problem: why does the coordinating feel like something?

Unity Denial: "does it only seem continuous to itself by illusion?" (James 1890, i: 200)

there are multiple parallel processes going all the time
when I reflect on the exercise ("Am I conscious now?"), "[t]hen and only then, is a temporary stream of consciousness concocted, making it seem as though we have been conscious all along." (255)

SB's summation: "Just as the fridge door is usually closed, so we are usually in a state of parallel multiple drafts. Only when we briefly open the door is the illusion created that the light is always on." (255-6)