But the knowledge of man, of the springs of his conduct, of his relation to his fellow-men singly or in groups, and the felicitous regulation of human intercourse in the interest of harmony and fairness, have made no such advance. Aristotle's treatises on astronomy and physics, and his notions of "generation and decay" and of chemical processes, have long gone by the board, but his politics and ethics are still revered. Does this mean that his penetration in the sciences of man exceeded so greatly his grasp of natural science, or does it mean that the progress of mankind in the scientific knowledge and regulation of human affairs has remained almost stationary for over two thousand years? I think that we may safely conclude that the latter is the case. It has required three centuries of scientific thought and of subtle inventions for its promotion to enable a modern chemist or physicist to center his attention on electrons and their relation to the mysterious nucleus of the atom, or to permit an embryologist to study the early stirrings of the fertilized egg. As yet relatively little of the same kind of thought has been brought to bear on human affairs. When we compare the discussions in the United States Senate in regard to the League of Nations with the consideration of a broken-down car in a roadside garage the contrast is shocking. The rural mechanic thinks scientifically; his only aim is to avail himself of his knowledge of the nature and workings of the car, with a view to making it run once more. The Senator, on the other hand, appears too often to have little idea of the nature and workings of nations, and he relies on rhetoric and appeals to vague fears and hopes or mere partisan animosity. The scientists have been busy for a century in revolutionizing the _practical_ relation of nations. The ocean is no longer a barrier, as it was in Washington's day, but to all intents and purposes a smooth avenue closely connecting, rather than safely separating, the eastern and western continents. The Senator will nevertheless unblushingly appeal to policies of a century back, suitable, mayhap, in their day, but now become a warning rather than a guide. The garage man, on the contrary, takes his mechanism as he finds it, and does not allow any mystic respect for the earlier forms of the gas engine to interfere with the needed adjustments.