> This is IMO a typical mistake that comes mostly from our Western metaphysical sense of seeing the body as specialized pieces that make up a whole, and not as a complete unit.

But this is the case! All the parts influence each other, sure, and some parts are reasonably multipurpose — but we can deduce quite certainly that the mind is a society of interconnected agents, not a single cohesive block. How else would subconscious urges work, much less acrasia, much less aphasia?