The Approach to Philosophy

by Ralph Barton Perry

In a similar vein, the earliest conceptions of natural evolution attributed it to the coworking of two principles, that of Love or union and that of Hate or dissolution. The process is here distinguished from the material of nature, but is still described in the language of practical life. A distinction between two aspects of vital phenomena is the next step. These may be regarded in respect either of the motion and change which attend them, or the rationality which informs them. Life is both effective and significant. Although neither of these ideas ever wholly ceases to be animistic, they may nevertheless be applied quite independently of one another. The one reduces the primitive animistic world to the lower end of its scale, the other construes it in terms of a purposive utility commensurable with that of human action. Now it is with mechanism, the former of these diverging ways, that the development of materialism is identified. For this philosophy a thing need have no value to justify its existence, nor any acting intelligence to which it may owe its origin. Its bulk and position are sufficient for its being, and the operation of forces capable of integrating, dividing, or moving it is sufficient for its derivation and history. In short, there is no rhyme or reason at the heart of things, but only actual matter distributed by sheer force. With this elimination of the element of purposiveness from the hylozoistic world, the content and process of nature are fitted to one another. Matter is that which is moved by force, and force is the determining principle of the motions of matter. Materialism is now definitely equipped with its fundamental conceptions.

Materialism and Physical Science.

§ [105]. The central conceptions of materialism as a philosophical theory differ from those employed in the physical sciences only in what is demanded of them. The scientist reports upon physical phenomena without accepting any further responsibility, while those who like Lucretius maintain a physical metaphysics, must, like him, prove that "the minute bodies of matter from everlasting continually uphold the sum of things." But, though they employ them in their own way, materialists and all other exponents of naturalism derive their central conceptions from the physical sciences, and so reflect the historical development through which these sciences have passed. To certain historical phases of physical science, in so far as these bear directly upon the meaning of naturalism, we now turn.

The Development of the Conceptions of Physical Science. Space and Matter.

§ [106]. From the earliest times down to the present day the groundwork of materialism has most commonly been cast in the form of an atomic theory. Democritus, the first system-builder of this school, adopted the conception of indivisible particles (ἄτομοι), impenetrable in their occupancy of space, and varying among themselves only in form, order, and position. To provide for the motion that distributes them he conceived them as separated from one another by empty space. From this it follows that the void is as real as matter, or, as Democritus himself is reputed to have said, "thing is not more real than no-thing."

But atomism has not been by any means universally regarded as the most satisfactory conception of the relation between space and matter. Not only does it require two kinds of being, with the different attributes of extension and hardness, respectively,[229:3] but it would also seem to be experimentally inadequate in the case of the more subtle physical processes, such as light. The former of these is a speculative consideration, and as such had no little weight with the French philosopher Descartes, whose divisions and definitions so profoundly affected the course of thought in these matters after the sixteenth century. Holding also "that a vacuum or space in which there is absolutely no body is repugnant to reason," and that an indivisible space-filling particle is self-contradictory, he was led to identify space and matter; that is, to make matter as indispensable to space as space to matter. There is, then, but one kind of corporeal being, whose attribute is extension, and whose modes are motion and rest. The most famous application of the mechanical conceptions which he bases upon this first principle, is his theory of the planets, which are conceived to be embedded in a transparent medium, and to move with it, vortex fashion, about the sun.[230:4]

But the conception of the space-filling continuity of material substance owes its prominence at the present time to the experimental hypothesis of ether. This substance, originally conceived to occupy the intermolecular spaces and to serve as a medium for the propagation of undulations, is now regarded by many physicists as replacing matter. "It is the great hope of science at the present day," says a contemporary exponent of naturalism, "that hard and heavy matter will be shown to be ether in motion."[231:5] Such a theory would reduce bodies to the relative displacements of parts of a continuous substance, which would be first of all defined as spacial, and would possess such further properties as special scientific hypotheses might require.

Two broadly contrasting theories thus appear: that which defines matter as a continuous substance coextensive with space; and that which defines it as a discrete substance divided by empty space. But both theories are seriously affected by the peculiarly significant development of the conception of force.

Motion and its Cause. Development and Extension of the Conception of Force.

§ [107]. In the Cartesian system the cause of motion was pressure within a plenum. But in the seventeenth century this notion encountered the system of Newton, a system which seemed to involve action at a distance. In the year 1728 Voltaire wrote from London: