With the disappearance at the Reformation of one of the great assumptions on which the mediaeval state had been based, a new theory of the state was inevitable. The national state of the seventeenth century was something new in history, and Hobbes differs from Aristotle, not because Hobbes is perverse and Aristotle right, though Hobbes often is perverse, but because the political problems which Hobbes and Aristotle had to face were not the same. Two great historical facts at the end of the eighteenth century, the French Revolution and the Industrial Revolution, profoundly modified the basis of political organization. The modern state in consequence differs in many important respects from any that have preceded it. It does not rest on the common acceptance of authority, either religious, as did the mediaeval state, or personal, as did the seventeenth-century state. Unlike the Greek city state, it is large. Its administration is concerned with millions who cannot be in personal relations to one another, or share the same intensive life. With the nineteenth century, then, a new chapter in the development of political theory begins as the peculiar problems of the modern state develop. Professor Dicey, in his _Law and Opinion in England_, has divided the century into two periods of political thought--Individualism and Collectivism--one marking the decrease, the other the increase of the power and authority of the state. When our period begins, the day of individualism was passing. Ever since the Reformation it had, in spite of Burke, dominated political theory. Two forces had given it strength--one idealistic, one scientific. It represented the revolt of the individual conscience against the claims of authority, and as such was a theory which attempted to limit the power of government over the individual, whether by an appeal to natural rights in Locke and Tom Paine, or to the greatest happiness of the greatest number in the Utilitarians, or to the super-eminent value of individual liberty as set forth in John Stuart Mill's noble panegyric. The French Revolution gave a notable impetus to this side of individualism, with its passionate assertion of the principle that political institutions exist for man, not man for political institutions, and that all government must be tested by the life which it enables each and every one of its citizens to live. Individualism in this sense is concerned with the discovery of principles by which the power of government over the lives of its members may be limited. It is not necessarily a theory of the nature of society. Hobbes, however, was an individualist as well as Locke, and for Hobbes the individual was the scientific unit from which societies and states were built up--the starting-point for a scientific treatment of society. As the French Revolution gave a fresh impulse to idealistic individualism, the Industrial Revolution reanimated the scientific, for