Note 1 — Chapter I

The word "evolution" is still used in so many different ways in various sciences that it is important to fix it in the general significance which we here give it. By "evolution," in the widest sense, I understand the unceasing "mutations of substance," adopting Spinoza's fundamental conception of substance; it unites inseparably in itself "matter and force (or energy)," or "nature and mind" (= the world and God). Hence the science of evolution in its broader range is "the history of substance," which postulates the general validity of "the law of substance." In the latter are combined "the law of the constancy of matter" (Lavoisier, 1789) and "the law of the conservation of energy" (Robert Mayer, 1842), however varied may be the changes of form of these elements in the world-process. Cf. Chapter XII. of The Riddle.