idea of physical forces is very probably derived from that of religious forces; then there cannot exist between the two the abyss which separates the rational from the irrational. Even the fact that religious forces are frequently conceived under the form of spiritual beings or conscious wills, is no proof of their irrationality. The reason has no repugnance _a priori_ to admitting that the so-called inanimate bodies should be directed by intelligences, just as the human body is, though contemporary science accommodates itself with difficulty to this hypothesis. When Leibniz proposed to conceive the external world as an immense society of minds, between which there were, and could be, only spiritual relations, he thought he was working as a rationalist, and saw nothing in this universal animism which could be offensive to the intellect. Moreover, the idea of the supernatural, as we understand it, dates only from to-day; in fact, it presupposes the contrary idea, of which it is the negation; but this idea is not at all primitive. In order to say that certain things are supernatural, it is necessary to have the sentiment that a _natural order of things_ exists, that is to say, that the phenomena of the universe are bound together by necessary relations, called laws. When this principle has once been admitted, all that is contrary to these laws must necessarily appear to be outside of nature, and consequently, of reason; for what is natural in this sense of the word, is also rational, these necessary relations only expressing the manner in which things are logically related. But this idea of universal determinism is of recent origin; even the greatest thinkers of classical antiquity never succeeded in becoming fully conscious of it. It is a conquest of the positive sciences; it is the postulate upon which they repose and which they have proved by their progress. Now as long as this was lacking or insufficiently established, the most marvellous events contained nothing which did not appear perfectly conceivable. So long as men did not know the immutability and the inflexibility of the order of things, and so long as they saw there the work of contingent wills, they found it natural that either these wills or others could modify them arbitrarily. That is why the miraculous interventions which the ancients attributed to their gods were not to their eyes miracles in the modern acceptation of the term. For them, they were beautiful, rare or terrible spectacles, or causes of surprise and marvel ([Greek: thaúmata], _mirabilia_, _miracula_); but they never saw in them glimpses of a mysterious world into which the reason cannot penetrate.