With the rest of us this innocence is lost. _Out of all the visual magnitudes of each known object we have selected one as the_ REAL _one to think of, and degraded all the others to serve as its signs_. This 'real' magnitude is determined by æsthetic and practical interests. It is that which we get when the object is at the distance most propitious for exact visual discrimination of its details. This is the distance at which we hold anything we are examining. Farther than this we see it too small, nearer too large. And the larger and the smaller feeling vanish in the act of suggesting this one, their more important _meaning_. As I look along the dining-table I overlook the fact that the farther plates and glasses _feel_ so much smaller than my own, for I _know_ that they are all equal in size; and the feeling of them, which is a present sensation, is eclipsed in the glare of the knowledge, which is a merely imagined one. If the inconsistencies of sight-spaces _inter se_ can thus be reduced, of course there can be no difficulty in equating sight-spaces with spaces given to touch. In this equation it is probably the touch-feeling which prevails as real and the sight which serves as sign--a reduction made necessary not only by the far greater constancy of felt over seen magnitudes, but by the greater practical interest which the sense of touch possesses for our lives. As a rule, things only benefit or harm us by coming into direct contact with our skin: sight is only a sort of anticipatory touch; the latter is, in Mr. Spencer's phrase, the 'mother-tongue of thought,' and the handmaid's idiom must be translated into the language of the mistress before it can speak clearly to the mind.[181] Later on we shall see that the feelings excited in the joints when a limb moves are used as signs of the path traversed by the extremity. But of this more anon. As for the equating of sound-, smell-, and taste-volumes with those yielded by the more discriminative senses, they are too vague to need any remark. It may be observed of pain, however, that its size has to be reduced to that of the normal tactile size of the organ which is its seat. A finger with a felon on it, and the pulses of the arteries therein, both 'feel' larger than we believe they really 'are.' It will have been noticed in the account given that _when two sensorial space-impressions, believed to come from the same object, differ, then_ THE ONE MOST INTERESTING, _practically or æsthetically_, IS JUDGED TO BE THE TRUE ONE. This law of interest holds throughout--though a permanent interest, like that of touch, may resist a strong but fleeting one like that of pain, as in the case just given of the felon. 3. _The Summation of the Sense-spaces._ Now for the next step in our construction of real space: _How are the various sense-spaces added together into a consolidated and unitary continuum?_ For they are, in man at all events, incoherent at the start.