The philosopher, Colin McGinn has listed five characteristics of mental states, which purportedly prevent them from being identified with brain states. Mental states are, he claims:
1. Unobservable — in the sense that they are not perceptible by means of the senses.
2. Asymmetrically accessible — in the sense that the owner of a mental state has a kind of immediate access to it that other people do not.
3. Subjective — in the sense that the nature of a mental state is knowable only from a single 'point of view'.
4. Non-spatial — in the sense that mental states do not take up a well-defined region of space.
5. Subject-dependent — in the sense that mental states only exist for a subject of awareness.
Now, as I argued a few weeks ago, non-commutative geometry is the best candidate for a mathematical structure which provides a common generalisation of the structures employed in quantum theory and relativity. And the crucial thing to note about non-commutative geometry is that it provides an algebraic representation of space, rather than a manifold of spatial points. Relationships between points in a manifold, such as spatial extension, are rendered obsolescent, and replaced with purely algebraic relationships. Hence, non-commutative geometry has the potential to dissolve one of the apparent barriers to resolving the mind-brain issue. McGinn's fourth point, that mental states are not spatially extended, is only a problem if brain states are held to be the states of spatially extended systems. Non-commutative geometry suggests that the spatial extension of any physical system, including the brain, is an illusion.
Thursday, April 19, 2007
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5 comments:
— Non-commutative geometry suggests that the spatial extension of any physical system, including the brain, is an illusion. —
Nonsense, you're confusing the map for the territory.
If a map of the world requires a Mercator projection to accurately represent distances, then it suggests that the world is round rather than flat. Similarly, if a representation of the structure of space-time requires non-commutative geometry to be accurate at small as well as large scales, then it suggests that space-time is not a manifold of points.
Clearly, but your post was about using non-commutative geometry to describe mental states, not space-time. That would lead to the claim that mental states do not have spacial extent, but that's begging the question in light of point (4).
A better analogy would be the claim that my computer can't fit on my desk because I can run Google Earth on it and clearly the Earth is bigger than my desk.
No, my post wasn't about using non-commutative geometry to describe mental states. My post was about using non-commutative geometry to describe space-time, and, perforce, all the physical systems in space-time, of which brains are one example.
The claim that mental states have no spatial extent is a separate premise, endorsed by McGinn. I sought to re-conceptualise the brain, using non-commutative geometry, in a way which would make it easier to reconcile the nature of mental states with the nature of the brain.
Ah - my mistake.
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