The moral commandments based upon divine authority were, in the nature of things, rather broad generalizations. Obviously there could not be special revelation as to the unique aspects of each human difficulty. The divine law, like our ordinary human law, was addressed to typical rather than to individual cases. Nevertheless, for much the greater part of recorded history men have accepted such law without questioning its validity. They could not have done so if the rules of morality had not, at least in some rough way, worked. It is not difficult to see why they worked. They were broad rules of conduct imposed [p136] upon people living close to the soil, upon people, therefore, whose ways of living changed little in the course of generations. The same situations were so nearly and so often repeated that a typical solution would on the whole be satisfactory. These typical solutions, such as we find in the Mosaic law or the code of Hammurabi, were no doubt the deposits of custom. They had, therefore, become perfected in practice, and were solidly based upon human experience. In the society in which they originated, there was nothing arbitrary or alien about them. When, therefore, the lawgiver carried these immemorial usages up with him on to Sinai, and brought them down again graven on tablets of stone, the rationality of the revelation was self-evident. It appeared to be arbitrary only when a radical change in the way of life dissolved the premises and the usages upon which the authoritative code was established. That dissolution has proceeded to great lengths within the centuries which we call modern. The crisis was reached, it seems, during the Eighteenth Century, and in the teaching of Immanuel Kant it was made manifest to the educated classes of the western world. Kant argued in the _Critique of Pure Reason_ that the existence of God cannot be demonstrated. He then insisted that without belief in God, freedom, and immortality, there was no valid and true morality. So he insisted that God must exist to justify morality. This highly sophisticated doctrine marks the end of simple theism in modern thought. For Kant’s proof of the existence of God was nothing but a plea that God ought to exist, and the whole temper [p137] of the modern intellect is to deny that what ought to be true necessarily is true.