Page:A Brief History of Modern Philosophy.djvu/83

 librarian, occupied with philosophy, mathematics, history and jurisprudence. His broadly comprehensive mind was capable of engaging productively in a wide range of subjects to their material advancement. He was everywhere affected by the controlling idea of continuity, which can only be rigorously carried through by the continual discovery of more numerous and finer distinctions and nuances of thought.

a. Leibnitz discovered a difficulty in Descartes’ and Spinoza’s theory that the sum total of motion in the universe always remains constant, namely, that it fails to explain how to account for motion and rest respectively in the various parts of the universe: They exist as antithetical states! Continuity can be established only through the concept of Force (or tendency, conatus). If motion has ceased at a given point in the universe, the Force still remains and can be revived again. Motion and rest are only relatively opposed to each other. Instead of the persistence of motion we should speak of the persistence of Force. Force is the factor in any given circumstance which contains the possibility of future change. We first discover a uniform relation between two states and we afterwards call the factor in the first state which makes the second state possible Force. The concept of Force therefore rests on the concept of law, the ultimate presupposition of which is the uniform consistency of changing states. Leibnitz calls this presupposition the principle of sufficient reason.

But how shall we account for the persistence of energy? According to Leibnitz this question can be answered only teleologically. If the energy of a cause were not preserved in the effect, nature would retrograde, which contradicts divine wisdom. Leibnitz thus finds a basis for his faith