Tuesday, January 19, 2010

Consciousness and the Brain

Ray Tallis makes a singularly unconvincing argument that consciousness cannot be described in terms of the activity of the brain, because the assessment of the question presupposes consciousness. It is as if the ability to defend a Theory of Gravitation depended on whether the observer was at the bottom of a gravity well.

Countering that objection by claiming that, say, activity in the occipital cortex and the sensation of light are two aspects of the same thing does not hold up because the existence of "aspects" depends on the prior existence of consciousness and cannot be used to explain the relationship between neural activity and consciousness.
His argument begins well enough, with two well-chewed-over problems of neurophilosophy: namely, the binding problem (how do disparate phenomena get integrated into a unified whole through consciousness?) and the qualia problem (what causes things to seem a certain way to a subjective observer? For example, the color red has a particular character to it.) He then proceeds to a nice summation of several interesting issues in the translation between psychology and neuroscience. There's also a note about the recent finding that many fMRI studies have suspiciously high correlations between brain states and behavior, higher than would be expected based on the technical limitations of the machines themselves.

Where he falls down is in the strange belief that...
"To do its work, physical science has to discard "secondary qualities", such as colour, warmth or cold, taste - in short, the basic contents of consciousness. For the physicist then, light is not in itself bright or colourful, it is a mixture of vibrations in an electromagnetic field of different frequencies. The material world, far from being the noisy, colourful, smelly place we live in, is colourless, silent, full of odourless molecules, atoms, particles, whose nature and behaviour is best described mathematically. In short, physical science is about the marginalisation, or even the disappearance, of phenomenal appearance/qualia, the redness of red wine or the smell of a smelly dog."
What's wrong with this is that it confuses a method of description with a point of view. Yes, in physics, we describe light in terms of wavelengths, sound in vibrations, and so forth. But the world that is described by these things is still described on our behalf; it is a parallel description of the qualia and other phenomena we are observing subjectively. It is still conscious beings who are doing the observing, whether we are observing brains or quasars. The world is not silent or colorless because we observe these phenomena using the language of mathematics or physics. Nor do brain studies, which are trying to describe our subjective experience in experimental terms, produce an insurmountable, self-contradictory state of affairs.

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