When men knew nothing of mechanics, nothing of the correlation of force, and of its indestructibility, they were believers in perpetual motion. So when chemistry was a kind of sleight-of-hand, or necromancy, something accomplished by the aid of the supernatural, people talked about the transmutation of metals, the universal solvent, and the philosopher's stone. Perpetual motion would be a mechanical miracle; and the transmutation of metals would be a miracle in chemistry; and if we could make the result of multiplying two by two five, that would be a miracle in mathematics. No one expects to find a circle the diameter of which is just one fourth of the circumference. If one could find such a circle, then there would be a miracle in geometry. In other words, there are no miracles in any science. The moment we understand a question or subject, the miraculous necessarily disappears. If anything actually happens in the chemical world, it will, under like conditions, happen again. No one need take an account of this result from the mouths of others: all can try the experiment for themselves. There is no caprice, and no accident. It is admitted, at least by the Protestant world, that the age of miracles has passed away, and, consequently, miracles cannot at present be established by miracles; they must be substantiated by the testimony of witnesses who are said by certain writers--or, rather, by uncertain writers--to have lived several centuries ago; and this testimony is given to us, not by the witnesses themselves, not by persons who say that they talked with those witnesses, but by unknown persons who did not give the sources of their information. The question is: Can miracles be established except by miracles? We know that the writers may have been mistaken. It is possible that they may have manufactured these accounts themselves. The witnesses may have told what they knew to be untrue, or they may have been honestly deceived, or the stories may have been true as at first told. Imagination may have added greatly to them, so that after several centuries of accretion a very simple truth was changed to a miracle. We must admit that all probabilities must be against miracles, for the reason that that which is probable cannot by any possibility be a miracle. Neither the probable nor the possible, so far as man is concerned, can be miraculous. The probability therefore says that the writers and witnesses were either mistaken or dishonest. We must admit that we have never seen a miracle ourselves, and we must admit that, according to our experience, there are no miracles. If we have mingled with the world, we are compelled to say that we have known a vast number of persons--including ourselves--to be mistaken, and many others who have failed to tell the exact truth. The probabilities are on the side of our experience, and, consequently, against the miraculous; and it is a necessity that the free mind moves along the path of least resistance.