As a matter of fact, those writers who proclaim the unknowability of the Real, when they are writing as philosophers, abandon it when they are engaged in science. When they are working out the theory of evolution, they take it for granted that the process of evolution is a reality, that the common experience of mankind is trustworthy to some extent, and that to that extent the Real is knowable and known. They assure us that, though the knowledge we have is not knowledge of the Real, it is just the same for us as if it were--if the Real could enter into our consciousness, we really should not know the difference. "Thus then we may resume, with entire confidence, those realistic conceptions which philosophy at first sight seems to dissipate."[8] On examination, however, it turns out that the entire confidence which is thus restored to the reality of material things is not extended to the reality of those ideals of the good, the beautiful, and the holy which play their part in the lives of men and in the evolution of mankind--or not to all of those ideals. Now, it is scarcely to be hoped that a theory which begins by ignoring certain facts in the common experience of mankind, or by denying their reality, can end in a satisfactory explanation of them. Either it will be consistent and proclaim them to be illusions, or it will be inconsistent and quietly include them from time to time as it goes on--in which case the explanation it gives of them will be no explanation. Thus, for instance, as we have already argued, the Optimistic interpretation of evolution, professing to exhibit the Ideal of morality as one of the ultimate consequences of the redistribution of matter and motion, ends by denying any difference between what is and what ought to be, and thus reduces the moral ideal to a mere illusion. The Pessimist, on the other hand, insisting on the reality, and to some extent the supremacy of the moral ideal, confesses his inability to explain its validity as being due to evolution: the fact that it has been evolved does not account for its validity, because the tendency to evil has been also evolved, but is not, therefore, to be yielded to. The object of this chapter is to examine the hypothesis that the process of evolution is nothing but a perpetual redistribution of matter and motion, and to show that the hypothesis cannot explain, and as a matter of fact does not explain, all the facts which it is framed to account for. The theory of evolution is an attempt--one of many attempts that men have made--to explain the process by which the totality of things has come to be what it is. It differs from most other attempts in that it endeavours to give a scientific explanation of the process, and that consequently it does not profess to go back to the beginning or to discover the origin of the process.