If we can truly take such a position, and hold it rationally, it is the modern science so apt to be decried by the bats and owls of orthodoxy that justifies us in doing so. For what is the philosophic purport of these beautiful and sublime discoveries with which the keen insight and patient diligence of modern students of science are beginning to be rewarded? What is the lesson that is taught alike by the correlation of forces, by spectrum analysis, by the revelations of chemistry as to the subtle behaviour of molecules inaccessible to the eye of sense, by the astronomy that is beginning to sketch the physical history of countless suns in the firmament, by the palæontology which is slowly unravelling the wonders of past life upon the earth through millions of ages? What is the grand lesson that is taught by all this? It is the lesson of the unity of nature. To learn it rightly is to learn that all the things that we can see and know, in the course of our life in this world, are so intimately woven together that nothing could be left out without reducing the whole marvellous scheme to chaos. Whatever else may be true, the conviction is brought home to us that in all this endless multifariousness there is one single principle at work, that all is tending toward an end that was involved from the very beginning, if one can speak of beginnings and ends where the process is eternal. The whole universe is animated by a single principle of life, and whatever we see in it, whether to our half-trained understanding and narrow experience it may seem to be good or bad, is an indispensable part of the stupendous scheme. As Aristotle said, so long ago, in one of those characteristic flashes of insight into the heart of things in which no one has ever excelled him, in nature there is nothing that is out of place or interpolated, as in an ill-constructed drama.