Page:Mind (Old Series) Volume 12.djvu/216

THE PEKCEPTION OF SPACE. (ll.) 203 different directions are contrasted within the same extent. If I extend my arm straight out at the shoulder the rotation of the shoulder-joint will give me one feeling of movement ; if then I sweep the arm forward, the same joint will give me another feeling of movement. Both these movements are felt to happen in space, and differ in specific quality. Why shall not the specificness of the quality just consist in the feeling of a peculiar direction? Why may not the several joint-feelings le so many perceptions of movement in so many different directions ? That we cannot explain why they should is no presumption that they do not, for we never can explain why any sense-organ should awaken the sensation it does. But if the joint-feelings are directions and extents, standing in relation to each other, the task of association in interpreting their import in eye- or skin-terms is a good deal simplified. Let the movement &c, of a certain joint, derive its absolute space-value from the cutaneous feeling it is always capable of engendering ; then the longer movement abed of the same joint will be judged to have a greater space-value, even though it may never have wholly merged with a skin-experience. So of differences of direction : so much joint-difference = so much skin-difference ; therefore more joint-difference = more skin-difference. In fact, the joint- feeling can excellently serve as a map on a reduced scale, of a reality which the imagination may project at its pleasure into this or that part of objective space. When the joint-feeling in itself acquires an emotional interest, which happens whenever the joint is inflamed and painful, the secondary suggestions fail to arise and the movement is felt where it is, and in its proper scale of magnitude. I have said hardly anything about associations with visual space in the foregoing account, because I wished to represent a process which the blind man and the seeing might equally share. It is to be noticed that the space suggested to the imagination and projected to the distance of the finger-tip is not represented as any such specific skin-tract as that of cheek or palm, by means of which the ' meaning ' of the joint-rotation may originally have been learned. What the mind imagines is rather a generic image, an abstraction from many skin-spaces whose local-signs have neutralised each other by blending, and left nothing but their common vast- ness behind. We shall see as we go on that this generic abstraction of space - magnitude from the various local peculiarities of feeling which accompanied it when it was