It is evident that with this restriction of the speculative horizon, they were and must remain wholly unable to emerge into the full light of the completely constituted science of society, with laws of movement as well as laws of equilibrium, with definite methods of interpreting past and predicting future states. They could account for and describe the genesis of the social union, as Plato and Aristotle had in different ways been able to do many centuries before; and they could prescribe some of the conditions of its being maintained in vigour and compactness. Some of them could even see in a vague way the interdependence of peoples and the community of the real interests of different nations, each nation, as De la Rivière expressed it, being only a province of the vast kingdom of nature, a branch from the same trunk as the rest.[45] What they could not see was the great fact of social evolution; and here too, in the succession of social states, there has been a natural and observable order. In a word, they tried to understand society without the aid of history. Consequently they laid down the truths which they discovered as absolute and fixed, when they were no more than conditional and relative. Fortunately inquirers in another field had set a movement afoot, which was destined to furnish the supplement of their own speculation. This was the remarkable development of the conception of history, which Montesquieu's two memorable books first made conspicuous. Bossuet's well-known discourse on universal history, teeming as it does with religious prejudice, just as Condorcet's sketch teems with prejudice against religion, and egregiously imperfect in execution as it must be pronounced when judged from even the meanest historical standard, had perhaps partially introduced the spirit of Universality, as Comte says, into the study of history. But it was impossible from the nature of the case for any theologian to know fully what this spirit means; and it was not until the very middle of the following century that any effective approach was made to that universality which Bossuet did little more than talk about. Then it came not from theology, but from the much more hopeful sources of a rational philosophy. Before Montesquieu no single stone of the foundation of scientific history can be said to have been laid. Of course, far earlier writers had sought after the circumstances which brought about a given transaction. Thucydides, for example, had attributed the cause of the Peloponnesian war to the alarm of the Lacedæmonians at the greatness of the power of Athens.[46] It is this sense of the need of explanation, however rudimentary it may be, which distinguishes the great historian from the chronicler, even from a very superior chronicler like Livy, who in his account of even so great an event as the Second Punic War plunges straightway into narrative of what happened, without concerning himself why it happened. Tacitus had begun