What has gone before is not a history of the natural law, but simply the consideration of selected developments within that history. The pattern, however, is not significantly altered, it would appear, in a complete history; and certain statements can be made with confidence. It can be said that the natural law, as an idea, is almost as old as philosophy itself. Since the Greeks first began to philosophize it has appeared in every age and can be described as a sort of recurring decimal in the history of thought. It has, of course, had its great moments and its moments of eclipse, its flowering times and barren times, catabolic and anabolic periods. It has been declared dead, never to rise again from its ashes; but it has risen livelier than ever and buried its undertakers. It is commonplace to observe that the funeral orations for the natural law have always been premature.¹ There is, indeed, no doubt of the revival of interest in the natural law in our time. Some, however, compare it with the interest of anatomists in a cadaver — and we have here, perhaps, part of the secret of the vitality of the concept; for the natural law requires to be justified anew in every age. It is not enough that there should be many upholders of the natural law in our day; what is required is that the concept should be shown to be sound and relevant in the conditions of our century.