Wednesday, November 23, 2005

Considering how we know (Pt. 3) ...

An email correspondent has suggested that the subject of these posts regarding neurologist Russell Brain's Mind, Perception and Science is wearisomely abstruse. And he may well be right. So I have decided to take the advice Brain himself offers in his Introduction and skip ahead a bit, to Chapter 4 and beyond, wherein he discusses the philosophical implications of the technical matters discussed earlier. In doing so I can actually get around to showing Bill Peschel where Brain was going with those of his observations I quoted in my original post.
Brain differentiates between two "worlds" -- the perceptual "world" and the physicl "world." (This is strictly a verbal distinction, made for the sake of argument; as he points out later, there is really only one world.)
The two "worlds" differ from one another in various respects. One of the most important of these is that events in the physical "world" occur "at different times from those at which the observer perceives them." This is obvious when one considers looking at an object light years away. But as Brain notes, the observer's perception of his own body also is "awareness of its immediate past, for he is not aware of the prick of a pin until after the interval of time necessary for a nerve-impulse to travel to his brain from the part of the body which has been pricked." That is because "what determines our awareness of a sensation, and also its nature, is the arrival of a nerve-impulse, or more probably a series of nerve-impulses, at the appropriate end-station of the brain."
This brings us to what Bill was interested in:
... if at least what the philosophers call secondary qualities, such as smells, sounds, colours and so on, are quite unlike the physical stimuli which give rise to them, then we must regard them as symbols of physical reality and say that the receptive function of the brain is to provide us with a symbolical representation of the world outside it, not only distinguishing objects by their qualities, but also conveying to us the spatial relationships which exist between them, and at the same time giving us similar symbolical information about our own bodies and their relation to the external world. (Emphasis mine.)
I think I'll leave it at there for now. That's a Thanksgiving Day's portion of food for thought.


  1. Happy Thanksgiving to you and yours, Frank.

  2. The same to you and your family also, Jeff. Safe and blessed.