M. Lionel Dauriac[1] enquires how it comes about that, while accepting the theory of Evolution, we write a book of 476 pages against its most illustrious exponent, and asks us to explain our acceptance of the doctrine as a whole. It is quite true, as he states, that we repudiate a materialistic explanation, and it is on this ground that we join issue with Mr. Spencer, inasmuch as, notwithstanding Mr. Spencer's own formal repudiation, all the formulas of explanation upon which he attempts the reconstruction of the universe are materialistic. The factors of chemistry, and the laws of physics, together with the laws of equilibration and polarity, are all purely materialistic in character. By the aid of these factors and these laws alone we do not think it possible to understand and explain the history of cosmical evolution. Do we then accept a spiritual evolution to which the materialistic has been altogether subordinate? No. We do not understand the operations of the subjective apart from the material organism. It seems to us that there are material factors, and factors which are subjective, and what is wanted is the law of their correlation. When we say that we accept Evolution, we mean that we accept the theory of an orderly progress from a state of indefinite, incoherent simplicity to a state of definite coherent complexity. We discern two sets or kinds of factors, the materialistic and the subjective, but we are unable sufficiently to understand them and their laws of correlation to lay down a formula of interaction of such a nature as to explain the orderly development which we recognise.