[Sidenote: The Task of Naturalism.] § 110. But these are the boasts of Homeric heroes before going into battle. The moment such a general position is assumed there arise sundry difficulties in the application of naturalistic principles to special interests and groups of facts. It is one thing to project a mechanical scheme in the large, but quite another to make explicit provision within it for the origin of nature, for life, for the human self with its ideals, and for society with its institutions. The naturalistic method of meeting these problems involves a reduction all along the line in the direction of such categories as are derived from the infra-organic world. That which is not like the planetary system must be construed as mechanical by indirection and subtlety. [Sidenote: The Origin of the Cosmos.] § 111. The origin of the present known natural world was the first philosophical question to be definitely met by science. The general form of solution which naturalism offers is anticipated in the most ancient theories of nature. These already suppose that the observed mechanical processes of the circular or periodic type, like the revolutions and rotations of the stars, are incidents in a historical mechanical process of a larger scale. Prior to the present fixed motions of the celestial bodies, the whole mass of cosmic matter participated in irregular motions analogous to present terrestrial redistributions. Such motions may be understood to have resulted in the integration of separate bodies, to which they at the same time imparted a rotary motion. It is such a hypothesis that Lucretius paints in his bold, impressionistic colors. But the development of mechanics paved the way for a definite scientific theory, the so-called "nebular hypothesis," announced by La Place in 1796, and by the philosopher Kant at a still earlier date. Largely through the Newtonian principle of the parallelogram of forces, the present masses, orbits, and velocities were analyzed into a more primitive process of concentration within a nebulous or highly diffused aggregate of matter. And with the aid of the principle of the conservation of energy this theory appears to make possible the derivation of heat, light, and other apparently non-mechanical processes from the same original energy of motion.