202 w. JAMES :

But if this is all so, it may well be asked : " Why do we feel the figure to be traced, not within the joint itself, but in such an altogether different place ? And why do we feel it so much larger than it really is ? " I will answer these questions by asking another : Why do we move our joints at all ? Surely to gain something more valuable than the insipid joint-feelings themselves. And these more interesting feelings (if we abstract from eye and ear) are in the main produced upon the skin of the moving part, or of some other part over which it passes. With movements of the fingers we explore the configuration of all real objects with which we have to deal, our own body as well as foreign things. Nothing that interests us is located in the joint ; everything that interests us either is, or coincides in place with, some part of our skin. The skin- spaces come thus to figure as the important ones for us to concern ourselves with. Every time the joint moves, even though no skin-sensation occurs, the reminiscence of skin- sensations which formerly coincided with that extent of movement, ideally awaken as the movement's import, and the mind drops the present sign to attend to the import alone. The joint-sensation itself, and as such, does not dis- appear in the process. A little attention easily detects it, with all its fine peculiarities, hidden beneath its vaster suggestions ; so that really the mind has two space- perceptions before it, congruent in form but different in scale and place, either of which exclusively it may notice, or both at once, the joint-space it feels and the real space it means. The joint-spaces serve so admirably as signs because of their capacity for parallel variation to all the peculiarities of external motion. There is not a direction in the real world nor a ratio of distance, which cannot be matched by some direction or extent of joint-rotation. Joint-feelings, like all feelings, are roomy. Specific ones are contrasted inter se as pression of the palatine mucous membrane are what occasion the feeling ; and I was at first astonished that, coming from so small an organ, it could appear so voluminous. Now the curious point is this that no sooner had I learnt by the eye its objective space-significance, than I found myself enabled mentally to feel it as a movement upwards of a body in the situa- tion of the uvula. When I now have it, my fancy injects it, so to speak, with the image of the rising uvula ; and it absorbs the image easily and naturally. In a word, a muscular contraction gave me a sensation whereof I was unable during forty years to interpret a motor meaning, of which two glances of the eye made me permanently the master. To my mind no further proof is needed of the fact that muscular contraction, merely as such, need not be perceived directly as so much motion through space.