A single purpose runs throughout this little book, though different aspects of it are treated in the three several parts. The first part, "The Mystery of Evil," written soon after "The Idea of God," was designed to supply some considerations which for the sake of conciseness had been omitted from that book. Its close kinship with the second part, "The Cosmic Roots of Love and Self-Sacrifice," will be at once apparent to the reader.
That second part is, with a few slight changes, the Phi Beta Kappa oration delivered by me at Harvard University, in June, 1895. Its original title was "Ethics in the Cosmic Process," and its form of statement was partly determined by the fact that it was intended as a reply to Huxley's famous Romanes lecture delivered at the University of Oxford in 1893. Readers of "The Destiny of Man" will observe that I have here repeated a portion of the argument of that book. The detection of the part played by the lengthening of infancy in the genesis of the human race is my own especial contribution to the Doctrine of Evolution, so that I naturally feel somewhat uncertain as to how far that subject is generally understood, and how far a brief allusion to it will suffice.a