Page:Popular Science Monthly Volume 20.djvu/460

444 Obscurity comes over the view when the physical sphere is exchanged for the ethical. It is easy, to admit that man is not free, but acts as the tool of hidden causes, so long as his conduct is indifferent. Whether Cæsar in thought put on his right or his left caliga first was all the same; in either case, he went out with his boots on. Whether he crossed the Rubicon or not, on that hung the world's history. So little are we free in some unimportant matters, that one acquainted with human nature can predict with surprising certainty which card out of several laid down under certain conditions we will take up first. But even the most decided monist could hardly adhere to the earnest purposes of practical life in the face of the idea that all of human existence is a fable convenue in which mechanical necessity awards to Caius the part of a traitor, and to Sempronius that of a judge; and therefore Caius is taken to execution, while Sempronius goes to his breakfast. We are not troubled that so many letters in every hundred thousand miscarry because they are not directed; but it stirs our moral feelings to think that, according to Quetelet, so many persons in every hundred thousand are to become thieves, murderers, and incendiaries; for it is painful to have to feel that we are not criminals only because others, instead of ourselves, have drawn the black lots that might have fallen to our share.

Less known than the metaphysical efforts to reconcile free-will and the moral law with the mechanical order of the world are the mathematical essays directed to the same end that have lately been put forth in France. They are related to the unsuccessful attempt of Descartes to explain the working of the soul upon the body, of the spiritual upon the material substance. While Descartes held that the quantity of motion in the world was constant, and did not believe that the soul could produce motion, he nevertheless thought that the soul might determine the direction in which motion should take place. Leibnitz showed that not the sum of motions but the sum of motive forces is constant, and that also the sum of the directive forces, or of the advance in the line of any axis projected in space, continues the same. He, therefore, called the algebraic sum of all those axes parallel components of all mechanical movements. According to the last point, which was overlooked by Descartes, the direction of motion can not be determined or changed without a corresponding expenditure of force. However small we may imagine this expenditure of force to be, it forms a part of the mechanism of nature, and can not be ascribed to the spiritual substance.

The deceased mathematician, Cournot, M. de Sainte-Venant, and Professor Boussinesq, of Lille, have undertaken to break the bands of mechanical determinism by showing that motion can be produced, or the direction of motion can be changed, without the expenditure of force. Cournot and M. de Sainte-Venant have applied the idea of release (Auflösung, Fr. décrochement), which has long been current in