Will this study of religion from the psychological standpoint prove to be an ally to the Christian Faith, or will it put new weapons into the hands of its enemies? It may be too early for a positive answer, but the advertising value of the new movement cannot be denied, and several specific entries at least may be made on the credit side of the ledger. The materials for religious psychology have been drawn mainly from Christian biography and Christian experience. Impressive stories of conversion, gathered from the ages of Christendom and from the work of city and foreign missions, have strengthened the argument from Christian experience. Taken from religious biographies and devotional books and missionary annals and modern questionnaires, the testimony of the saints of all ages has been marshalled as they have told what the Lord has done for their souls. The very fact that it has been worth while to write psychologies of religion is in itself significant. "Christianity," says Eucken, "has been the first to give the soul a history; in comparison with the interest of the soul, it has reduced all events in the outer world to mere incidentals, according to the words of Jesus: 'What shall it profit a man if he gain the whole world and lose his own soul.'"[92] 92: "Können wir noch Christen sein?" 1911, p. 10; "Can We Still Be Christians?" p. 9. Separating as far as possible the descriptive from the metaphysical aspects of our subject, we may consider I. The Psychology of Religious Experience; and II. The Metaphysical Implicates of Religious Experience. Under the first head we shall find that the study of religious experience has been favourable to the Christian Faith in at least four respects. I. THE PSYCHOLOGY OF RELIGIOUS EXPERIENCE I. The scientific study of religion shows that religion belongs to the essence rather than the accidents of human nature. Man is the praying, the believing, and the hoping-to-survive animal. It is not the office of psychology to prove the existence of God, but it may show that belief in His existence is natural to man, and is favoured by natural selection. It may show that religious experiences have, in the words of James, "enormous biological worth,"[93] and that, to quote again the same writer, "the strenuous type of character will on the battle-field of human history always outwear the easy-going type, and religion will drive irreligion to the wall."[94] 93: "Varieties of Religious Experience," p. 509. 94: "The Will to Believe," p. 213.