THE PERCEPTION OF SPACE. (ll.) 211

larger on a map the distance would look than others with whose totality we are familiar. I am disposed to believe, after interrogating many blind persons, that the use of imaginary maps on a reduced scale is not as frequent with them as with the rest of us. Possibly the extraordinary changeableness of the visual magnitudes of things makes this habit natural to us, while the fixity of tactile magnitudes keeps them from falling into it. (When the blind young man operated on by Dr. Franz was shown a portrait in a locket, he was vastly surprised that the face could be put into so small a compass : it would have seemed to him, he said, as impossible as to put a bushel into a pint.) Be this as it may, however, the space which each blind man feels to extend beyond his body is felt by him as one smooth continuum all trace of those muscular startings and stoppings and reversals which pre- sided over its formation having been eliminated from the memory. It seems, in other words, a generic image of the space-element common to all these experiences, with the unessential particularities of each left out. In truth, where in this space a start or a stop may have occurred, was quite accidental. It may never occur just there again, and so the attention lets it drop altogether. Even as long a space as that traversed in a several- mile walk will not necessarily appear to a blind man's thought in the guise of a series of locomotor acts. Only where there is some distinct locomotor difficulty, such as a step to ascend, a difficult crossing, or a disappearance of the path, will distinct locomotor images constitute the idea. Elsewhere the space seems continuous, and its parts may even all seem co-existent ; though, as a very intelligent blind friend once remarked to me, " To think of such distances involves probably more mental wear and tear and brain-waste in the blind than in the seeing". This seems to jxrint to a greater element of successive addition and construction in the blind man's idea. Our own visual explorations go on by means of innumerable stoppings and startings of the eyeballs. Yet these are all effaced from the final space- sphere of our visual imagination. They have neutralised each other. We can even distribute our attention to the right and left sides simultaneously, and think of those two quarters of space as co-existent. Does the smooth- ing out of the locomotor interruptions from the blind man's tactile space- sphere offer any greater paradox ? Surely not. And it is curious to note that both in him and in us there is one particular locomotor feeling that is apt to assert itself obstinately to the last. We and he alike spontaneously imagine space as lying in front of us, for reasons too obvious to enumerate. If we think of the space behind us we, as a rule, have to turn round mentally, and in doing so the front space vanishes. But in this, as in the other things of which we have been talking, individuals differ widely. Some, in ima- gining a room, can think of all its six surfaces at once like Mr. Galton's correspondents quoted in MIND v. 315. Others mentally turn round, or, at least, imagine the room in several successive and mutually exclusive acts. Sir Wm. Hamilton (Lects. on Metaphysics, ii. 174) has, by resuscitating it, given to the foolish opinion of a German philosopher of the last century, Platner, greater currency among us than it deserves. Platner says : " The attentive observation of a person born blind . . . has convinced me that the sense of touch by itself is altogether incompetent to afford us the representation of extension and space. ... In fact, to those born blind, time serves instead of space. Vicinity and distance mean in their mouths nothing more than the shorter or longer time . . . necessary to attain from some one feeling to some other." It is needless to remark on the utterly arbitrary and fanciful character of such an interpretation. No opinion is so silly but it will find some " learned Theban " to defend it. Platner's doc- trine may well pair off with that of Brown, the Mills and other English psychologists, who hold colours to be primitively seen without extension.