Hobbes was able to carry out his plan in some twenty years or more from the time of its conception, but the execution was so broken in upon by political events, and so complicated with other labours, that its stages can hardly be followed without some previous understanding of the relations of the parts of the scheme, as there is reason to believe they were sketched out from the beginning. His scheme was first to work out, in a separate treatise _De corpore_, a systematic doctrine of Body, showing how physical phenomena were universally explicable in terms of motion, as motion or mechanical action was then (through Galileo and others) understood--the theory of motion being applied in the light of mathematical science, after quantity, the subject-matter of mathematics, had been duly considered in its place among the fundamental conceptions of philosophy, and a clear indication had been given, at first starting, of the logical ground and method of all philosophical inquiry. He would then single out Man from the realm of nature, and, in a treatise _De homine_, show what specific bodily motions were involved in the production of the peculiar phenomena of sensation and knowledge, as also of the affections and passions thence resulting, whereby man came into relation with man. Finally he would consider, in a crowning treatise _De cive_, how men, being naturally rivals or foes, were moved to enter into the better relation of Society, and demonstrate how this grand product of human wit must be regulated if men were not to fall back into brutishness and misery. Thus he proposed to unite in one coherent whole the separate phenomena of Body, Man and the State.