Bergson's Creative Evolution, his largest and best known work, appeared in 1907. It has been regarded not only as a magnificent book, but as a date in the history of thought. Two of the leading students of evolutionary process in England, Professors Geddes and Thomson, refer to the book as "one of the most profound and original contributions to the philosophical consideration of the theory of Evolution." [Footnote: In the Bibliography in their volume Evolution.] For some time there had been growing a need for an expression of evolutionary theory in terms other than those of Spencer, or of Haeckel--the German monistic philosopher. The advance in the study of biology and the rise of Neo-Vitalism, occasioned by an appreciation of the inadequacy of any explanation of life in terms purely physical and chemical, made the demand for a new statement, in greater harmony with these views, imperative. To satisfy this demand is the task to which Bergson has applied himself. He sounds the note of departure from the older conceptions right at the commencement by his very title, 'Creative' Evolution. For this, his views on Change, on Time, and on Freedom, have in some degree prepared us. We have seen set forth the fact of Freedom, the recognition of human beings as centres of indetermination, not mere units in a machine, "a block universe" where all is "given," but creatures capable of creative activity. Then by a consideration of Time, as la duree, we found that the history of an individual can never repeat itself; "For a conscious being, to exist is to change, to change is to mature, to mature is to go on creating oneself endlessly. Should the same be said," Bergson asks, "of existence in general?" [Footnote: Creative Evolution, p. 8 (Fr. p. 8).]