Sunday, January 27, 2013

Patricia Churchland on the neurobiology of consciousness

I find the following article by Churchland informative on a number of levels. First, she clarifies that her brand of reductionism does not assume that the parts can fully determine the whole, but that they certainly have influence and constrain the possibilities. Second, that the whole exemplifies systematic network properties that "are never a simple 'sum of the parts.'" Finally, that this system called conscious awareness is likely tied to a bodily-based self representational 'perspective.' I find this fascinating because this is what we might call 'the self,' that awareness that distinguishes us from some other, and that we represent to ourselves with perspectives like I, you, he/she/it. Which is of course how Lakoff and company view it at presented in Feldman's book, From molecules to metaphor: A neural theory of language. See for example p. 130 and following on image schemas as perspectives. Note that Damasio (below) is referenced liberally throughout the book.

Excerpts from "Can neurobiology teach us anything about consciousness?":

"May I say that I do not mean that a reductionist research strategy implies that a purely bottom-up strategy should be adopted.... So far as neuroscience and psychology are concerned, my view is simply that it would be wisest to conduct research on many levels simultaneously, from the molecular, through to networks, systems, brain areas, and of course behavior. Here, as elsewhere in science, hypotheses at various levels can co-evolve as they correct and inform one another.

"By reductionist research strategy I do not mean that there is something disreputable, unscientific or otherwise unsavory about high level descriptions or capacities per se.... 'Emergence' in this context is entirely non-spooky and respectable, meaning, to a first approximation, 'property of the network.' Determining precisely what the network property is, for some particular feat, will naturally take quite a lot of experimental effort. Moreover, given that neuronal behavior is highly nonlinear, the network properties are never a simple 'sum of the parts.' They are some function -- some complicated function -- of the properties of the parts. High level capacities clearly exist, and high level descriptions are therefore needed to specify them.

"As Kant might have said to Hume, the brain will not produce awareness unless the nervous system also generates a representation of self -- a representation which carries what we would call 'a point of view.' And this is indeed precisely the hypothesis tendered by Antonio Damasio (1994). According to the Damasio perspective, the neurobiological mechanisms for visual awareness, for example, are essentially interconnected with the mechanisms for representing oneself as a thing that has experiences, that feels, remembers and plans; as a thing occupying space and enduring through time. To suppose that visual awareness can be understood independently of the self-representation is like supposing evolution can be understood independently of environment.

"Damasio's ideas on this score have emerged from many years of observing brain damaged patients, and reflecting on the ways in which awareness is related to self-representation and how that in turn is related to body-representation (For the details of his hypothesis, see his book, Descartes' Error 1994). Against a backdrop of basic neuroanatomy and neurophysiology, Damasio sees representational complexity and interdependence as key elements in explaining consciousness.... Damasio's central idea is both powerful and reasonable: body-representation, which systematically integrates bodily-stimulation and body-state information, provides a scaffolding for self-representation, and self-representation is the anchor point for awareness -- modality specific and otherwise."


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