Development Of The Human Soul

Appendix 9. (1217).

If a wheel rotates quickly, the eye can no longer discern the spokes of the wheel. It fuses them together as though they were continued planes rather than slender spokes. This happens through the extremely rapid change of sensations which overtake another in the optic sensory. The fact is indubitable, and provides powerful confirmation of what I set out to prove. Granted high speed in the wheel, fusion is present in the sensory which receives impressions with too rapid a succession. We have to say that, if the wheel rotates less quickly so that the eye can distinguish its spokes, impressions follow one another less quickly with the result that each impression endures sufficiently long to be distinguished by the intuiting subject. But impressions follow one another in proportion to the quickness of the passage of the different states of the wheel they represent. If, therefore, impressions endure in the case of lower speed, it is necessary that successive states of the wheel also endure. Hence, the wheel does not run with continuous motion. Here we have already a physical demonstration that the motion of the wheel is not continuous as we normally believe.

But we can also prove from observation that fusion of the sensations is the result of the wheel's moving too quickly. The impressions made on the eye by the wheel follow one another with extreme speed so that a preceding sensation, which perhaps is not fully formed, is cancelled by a following sensation. In fact, if a wheel rotating swiftly in the dark is suddenly illuminated by a flash, the eye which receives the impression of the flash immediately distinguishes the spokes as if the wheel were stationary. The first impression has time to be formed into a sensation and be adverted to because there is no other impression. - Moreover, there is also an evident proof, from dreams, that the phenomenon of continuity of motion arises in feeling even when continuous motion is lacking in the external body. Movement is present in dreams. Sometimes we dream that we are running, or that we see other objects, persons or things, move swiftly with continuous motion. But outside ourselves no body corresponds to the representation of the phantasm; in other words, there is nothing moving outside us, either with continuous motion or any other kind. It may perhaps be objected that continuous movement is present in the molecules of our brain, the organ of phantasy, and that these lend themselves to the production of the scene of movement in our inner sensory.

This, however, is impossible; the images do not arise in any way through movement on the part of molecules, but of molecules acting upon one another in such harmony that the image corresponds in all its parts to the corresponding movements of the group of molecules. We can see this in the coloured images of the eye which are aroused only if a fascia of rays disposed in different colours contemporaneously touches the retina. These rays are distributed according to the colours of the image which they arouse through the image in feeling. Hence, when we see a person running in a dream, we have to suppose that many images of the person follow one another granted that corresponding, harmonious movements follow one another in a band, as it were, of the brain. We can never suppose that the image itself runs through the brain. Nor can we suppose that the movements of the image aroused in the first tiny period of time run through the brain. In this case (if it were possible) we would not see the image run through the brain; the image would change into various bands of colour. The apparent motion, therefore, comes about through a number of ever-new, stationary images which succeed one another as a result of corresponding movements aroused in various tiny, tightly packed spaces of the brain. Each of these images lasts for the brief period necessary for its formation, for being distinguished and for memorisation.