Page:Philosophical Review Volume 5.djvu/223

207 a priori form imposed necessarily upon our sensibility. It is wholly a matter of expediency. But are not all objects represented in geometrical space? No, but we may reason about them as if they were. 'Localizing' an object in space means representing the movements necessary to reach it. What then is the significance of geometrical space? Phenomena are (1) Involuntary—not accompanied by muscular sensations and so attributed to external objects, or (2) Voluntary—accompanied by muscular sensations and attributed to our own body. Among the changes in (1) are some which can be 'corrected' by correlative changes in (2). The laws of this process of correction constitute the Science of Geometry. Such correction is only possible in the case of solid bodies. Geometry deals therefore with only one particular phase of space experience in general, viz., adjustments involving solidity. Were there no solids in nature there would be no Geometry. The three dimensions of geometrical space are due to the fact that we happen to be constituted as we are, and happen to live in this particular kind of world. In a different world and for a different self, space might have fewer or more dimensions. Finally, though experience plays so large a part in geometry, the latter is not an experiential science, for it is occupied not with actual but with ideal solids.

The author's conclusions may be summed up as follows, (1) All statements of the nature of a 'thing' are, for the most part, statements of origin. (2) Statements of origin, however, never exhaust the reality of a thing, since they cannot be true to the experiences which they state unless they construe the reality, not only as a thing which has had a career, but also as one which is about to have a career; for the expectation of the future career rests upon the same historical series as the belief in the past career. (3) All attempts to rule out prospective organization or teleology from the world would be fatal to natural science, and also to the historical interpretation of the world found in the evolution hypothesis; for the category of teleology is but the prospective reading of the same series which, when read retrospectively, we call evolution. (4) The fact that a thing, and more especially mental products, ideas, intuitions, etc., have a natural history, is no argument against their validity or worth as having application beyond the details of their own