And, indeed, as regards the working of the speculative faculty in the creation of history, it is in all respects marvellous how that the most truthful accounts of the passage from barbarism to civilisation in ancient literature come from the works of poets. The elaborate researches of Mr. Tylor and Sir John Lubbock have done little more than verify the theories put forward in the _Prometheus Bound_ and the _De Natura Rerum_; yet neither Æschylus nor Lucretias followed in the modern path, but rather attained to truth by a certain almost mystic power of creative imagination, such as we now seek to banish from science as a dangerous power, though to it science seems to owe many of its most splendid generalities. {43} Leaving then the question of the origin of society as treated by the ancients, I shall now turn to the other and the more important question of how far they may he said to have attained to what we call the philosophy of history. Now at the outset we must note that, while the conceptions of law and order have been universally received as the governing principles of the phenomena of nature in the sphere of physical science, yet their intrusion into the domain of history and the life of man has always been met with a strong opposition, on the ground of the incalculable nature of two great forces acting on human action, a certain causeless spontaneity which men call free will, and the extra-natural interference which they attribute as a constant attribute to God. Now, that there is a science of the apparently variable phenomena of history is a conception which _we_ have perhaps only recently begun to appreciate; yet, like all other great thoughts, it seems to have come to the Greek mind spontaneously, through a certain splendour of imagination, in the morning tide of their civilisation, before inductive research had armed them with the instruments of verification. For I think it is possible to discern in some of the mystic speculations of the early Greek thinkers that desire to discover what is that ‘invariable existence of which there are variable states,’ and to incorporate it in some one formula of law which may serve to explain the different manifestations of all organic bodies, _man included_, which is the germ of the philosophy of history; the germ indeed of an idea of which it is not too much to say that on it any kind of historical criticism, worthy of the name, must ultimately rest. For the very first requisite for any scientific conception of history is the doctrine of uniform sequence: in other words, that certain events having happened, certain other events corresponding to them will happen also; that the past is the key of the future.