Page:Mary Whiton Calkins - The Idealist to the Realist (The Journal of Philosophy, Psychology and Scientific Methods, 1911-08-17).pdf/9

 were thus perceivable.” The underlying character here is the spatialness, and the argument, already outlined, concerning concrete sense objects, shows equally that atoms and molecules, as spatial, are ideal. The modern conception of the atom as a complex of subatoms, centers of negative electricity in a sphere of positive electrification, reduce to the conceptions of spatial position, of motion, and of force.

2. A second view of the universe as ultimately physical conceives it as ether. By ether is meant a continuous and incompressible medium. But continuity is obviously spatial, and incompressibility is tangible. Moreover the ether is regarded either as (a) containing or as made up of moving particles-in other words, of spatial and tangible realities-or else as (b) pervaded by strain forms. In either case the conception of ether includes that of motion-and motion is succession of positions, that is, a complex of spatial quality and temporal relation. In the whole conception there is, for the scientist, much difficulty in meeting the rival requirements of the groups of facts which ether is hypothesized to explain; but no description of the ether in other than terms of sensible quality and relation has ever been put forward.

3. We turn finally to the conception of the universe as a complex of different sorts of energy. Here, too, we find the physicists at odds among themselves. Energy is usually defined as capacity for work. Narrowly scrutinized, this statement means simply that energy is conceived as the further undefined cause of phenomena; and energy is thus reduced to a relation, causality, already claimed by the idealist as ideal. Many of those who conceive of reality as energy, seem, however, to mean by energy force. But force is defined in one of three ways: either as resistance, a quality directly revealed through muscular sensation; or as cause of motion; or as no more nor less than a mathematical ratio, a measure of motion—the force of B on A being defined as “the product of the mass of A into the acceleration of A due to the presence of B.” But each one of these is a conception of ideal, not of non-ideal, reality. A mathematical relation is a mental conception; the resistance or stress which (to quote Montague) is immediately felt when a man places "his hand between a fixed spring and a body moving uniformly into collision with it," is a sensible quality; and motion, as has appeared, is made up of spatial quality and of temporal relation. All this is virtually admitted by many