PSYCHOLOGY AND DEVELOPMENT OF GEOMETRY 39
narrow boundaries of the domains of sense that constitute their peculiar foundation.
THE ROLE OF BODIES.
Isolated sensations have independent significance only in the lowest stages of animal life; as, for example, in reflex motions, in the removal of some disagreeable irritation of the skin, in the snapping reflex of the frog, etc. In the higher stages, attention is directed, not to space-sensation alone, but to those intricate and intimate complexes of other sensations with space-sensations which we call bodies. Bodies arouse our interest; they are the objects of our activities. But the character of our activities is coinci-dently determined by the place of the body, whether near or far, whether above or below, etc.,—in other words, by the space-sensations characterizing that body. The mode of reaction is thus determined by which the body can be reached, whether by extending the arms, by taking few or many steps, by hurling missiles, or what not. The quantity of sensitive elements which a body excites, the number of places which it covers, that is to say, the volume of the body, is, all other things being the same, proportional to its capacity for satisfying our needs, and possesses a consequent biological import. Although our sensations of sight and touch are primarily produced only by the surfaces of bodies, nevertheless powerful associations impel especially primitive man to imagine more, or, as he thinks, to per-ose their freedom." And his assertion, together with the tirades of Lactantiuso remark that physiologicalrans. Page 59.7.