Consciousness: Egnor on dualism (General)

by dhw, Wednesday, November 29, 2017, 18:38 (2549 days ago) @ David Turell

dhw: A very interesting essay, and I doubt if even a materialist would disagree with the distinction between material and immaterial powers. The question is not what we can do, but what is the SOURCE of what we can do. However, before passing any further comment, I need your professional expertise. It’s clear from the pictures that there are areas of the brain the twins do NOT share, whereas the article only dwells on those they do. I’d be grateful if you would tell us exactly which parts of the brain they do NOT share, and what functions those parts are normally associated with.

DAVID: Basically they share some sensory and motor controls, but there seems to be some prefrontal connection since they appear at times to read each others thoughts. And they share some posterior cortical information (vision). All of this seems quite clear to Egnor, short of doing an autopsy. The key to his discussion is that they are clearly separate personalities despite the connectivity. This would mean the way they speak and express their thoughts are separate. Speech is in a middle area of the cortex as is the motor control strip. There is no 'exactly' that I can give you. What is it you want and why?

I know what is meant by separate personalities. But if this is to be regarded as proof of dualism, we need to know which parts of the brain are joined and which are separate. Egnor only tells us about some parts that are shared (as you say, they are mainly sensory and motor). If other parts of the brain are responsible for thought and personality, as materialists believe, and those parts are separate, the case for dualism is far from proven. I noticed in the pictures that the back of one head is joined to one front side of the other (not really much “pre-frontal connection”), but I don’t know enough about the brain to tell how significant this might be. If “pre-frontal” sections help to form personality (materialist approach), then Egnor’s “evidence” for dualism is badly weakened. But I’m not prejudging – I’d just like to know. And thank you again for telling us about this extraordinary case