"But," it may be urged, "if it is impossible to prove that there ever was any instance of supernatural power, it is equally impossible to prove that there was not. The positive savant who denies the supernatural, argues as gratuitously as the credulous one who admits it!" Not at all. It is the duty of him who affirms a proposition to prove it, while he to whom the affirmation is made has only to listen to the proof and to decide whether it is satisfactory. If any one had asked Buffon to give a place in his _Natural History_ to sirens and centaurs, he would have answered: "Show me a specimen of these beings and I will admit them; until then, I do not admit their existence." "But can you prove that they do not exist?" the other may say, and Buffon would reply: "It is your province to prove that they do exist." In science the burden of proof rests on those who advance alleged facts. Why, although innumerable historic writings claim their existence, do people no longer believe in angels and demons? Simply because the existence of an angel or a demon has never yet been proved. In support of the reality of miraculous agency, appeal is made to phenomena outside of the course of natural laws, such, for instance, as the creation of man. This creation, it has been said, could only have been compassed by the direct intervention of the Divinity, and why was not this intervention manifested at other decisive crises of the development of the universe? I shall not dwell upon the strange philosophy and sordid appreciation of the Divinity manifested in such a system of reasoning. History should have its method, independent of all philosophy. Without at all entering upon the domain of theology, it is easy to show how defective is this argument. It is equivalent to maintaining that everything which does not happen in the ordinary conditions of the world, everything that cannot be explained by the present rules of science, is miraculous. But, according to this, the sun is a miracle, because science has never explained the sun; the conception of mankind is a miracle, because physiology is silent on that point; conscience is a miracle, because it is an absolute mystery; and every animal is a miracle, because the origin of life is a problem of which we know next to nothing. The reply that every life, every soul, is of an order superior to nature, is simply a play upon words. So we understand it, and yet the word miracle remains to be explained. How is that a miracle which happens every day and hour? The miraculous is not simply the inexplicable, it is a formal derogation from recognised laws in the name of a particular desire. What we deny to the miracle is the exceptional state or the results of particular intervention, as in the case of a clockmaker who may have made a clock very handsome to look at, but requiring at intervals the hand of its maker to supply a deficiency in its mechanism. We acknowledge