Chemistry of the Notions and the Feelings.—Philosophical problems, in almost all their aspects, present themselves in the same interrogative formula now that they did two thousand years ago: how can a thing develop out of its antithesis? for example, the reasonable from the non-reasonable, the animate from the inanimate, the logical from the illogical, altruism from egoism, disinterestedness from greed, truth from error? The metaphysical philosophy formerly steered itself clear of this difficulty to such extent as to repudiate the evolution of one thing from another and to assign a miraculous origin to what it deemed highest and best, due to the very nature and being of the "thing-in-itself." The historical philosophy, on the other hand, which can no longer be viewed apart from physical science, the youngest of all philosophical methods, discovered experimentally (and its results will probably always be the same) that there is no antithesis whatever, except in the usual exaggerations of popular or metaphysical comprehension, and that an error of the reason is at the bottom of such contradiction. According to its explanation, there is, strictly speaking, neither unselfish conduct, nor a wholly disinterested point of view. Both are simply sublimations in which the basic element seems almost evaporated and betrays its presence only to the keenest observation. All that we need and that could possibly be given us in the present state of development of the sciences, is a chemistry of the moral, religious, aesthetic conceptions and feeling, as well as of those emotions which we experience in the affairs, great and small, of society and civilization, and which we are sensible of even in solitude.