It was no part of the plan of this book to undertake a direct criticism of theories of evolution upon their merits, whether from the point of view of biology or of philosophy, of science or of metaphysics. If we now find it necessary to undertake an estimate of the value of Darwinism, we do so not merely because of the outstanding importance of that theory, but because, in summing up results, we are led to insist on a distinction. While we admit, and even (so far as we have any right to speak) defend, the theory of natural selection in biology, we affirm that it cannot be applied in sociology or morals. Such a view seems to need justification. It can only be supported by a review, however hurried and imperfect, of the merits of Darwinism.

The question may perhaps best be approached by a discussion of the element of chance contained, or said to be contained, in the Darwinian theory. Perhaps some minds love Darwinism, because it appeals to chance ; others undoubtedly distrust and despise it for that reason. What is chance? Does Darwinism assert chance, and, if so, in what sense? How far is it warranted in doing so?

First and most simply, chance is the opposite of purpose. It implies a failure of purpose where the presence of purpose and its successful realisation were expected.