Dr. Selbie is certainly preparing his students for these encounters, and preparing them, too, with an emphasis on one particular aspect of the old theology, and a central one, which the apologists of more orthodox communions have either overlooked or find it convenient to ignore. One of his first postulates is that man inhabits a moral universe, and from this postulate he has no difficulty in moving forward not only to contemplate the hypothesis of immortality, but to confront the difficulty of punishment for sin. In a little book of his called _Belief and Life_ he has the following passages: In the long last men cannot be persuaded to deny their own moral nature, and they will not be content with a theory of the universe which does not satisfy their sense of right. And because of this very sense of right they entertain no soft and sentimental notions concerning the universe: They believe in judgment, in retribution, and in the great principle that "as a man sows, so shall he also reap." They therefore require that room shall be found in the scheme of things for the working out of this principle. They recognise that such room is not to be found in this present life, and so they accept the fact that God hath set eternity in our hearts, and that we are built on a scale which requires a more abundant life to complete it. In corroboration of their faith, it may be said, as John Stuart Mill used to argue, that wherever belief in the future has been strong and vivid, it has made for human progress. There is no doubt that the deterioration of religion and the more material views of life so prevalent just now are due to the loss of faith in the future. Religion, he says, can never live or be effective within the narrow circle of time and sense. Nevertheless he has the courage to say: "The future life, like the belief in God, is best treated as an hypothesis that is yet in process of verification." But this hypothesis explains what else were inexplicable. It works. And, confronting the hypothesis of immortality, he insists that a future life must embrace retribution. "As a man sows, so shall he also reap." Immortality is not to be regarded as a sentimental compensation for our terrestrial experience, but as the essential continuity of our spiritual evolution. "For many, no doubt, it will mean an experience of probation, and for all one of retribution." He sees clearly and gratefully that "the moral range of the work of Christ in the human soul, His gifts of grace, forgiveness, and power, lift men at once on to the plane of the spiritual and fill their conception of life with a new and richer content." But he does not shut his eyes to the fact of the moral law, and with all the force of his character and all the strength of his intellect he accepts "the great principle that as a man sows, so shall he also reap."