It was well toward the beginning of the last century before philosophical doctrines rose above mere speculation, and were based upon the actual observation of phenomena. As the scientific method of gathering facts and reasoning from them became established, it was observed that in all probability the great laws of nature were themselves controlled by some greater law. While many attempts have been made to formulate this law, yet it must be confessed, frankly, that only the faintest outline of it is possesesd by the world of science. The sanest of modern philosophers, and the one who most completely attempted to follow the method of science in philosophical writings, was Herbert Spencer. Early in his life, he set himself the task of constructing a system of philosophy which should be built upon man's reliable knowledge of nature. A long life permitted him to realize this ambition. Though his works are filled with conclusions which cannot be accepted by most men, yet the facts used in his reasoning are authentic. By the world at large, the philosophy of Herbert Spencer is considered the only philosophy that harmonizes with the knowledge of today. [Sidenote: All things are continually changing.--This is the foundation of evolution.] After having discussed, with considerable fullness, the elements of natural phenomena, such as space, time, matter, motion and force, Mr. Spencer concludes that all evidence agrees in showing that "every object, no less than the aggregate of objects, undergoes from instant to instant some alteration of state."[A] That is to say that while the universe is one of system and order, no object remains exactly as it is, but changes every instant of time. [Footnote A: First Principles, p. 287.] In two directions only can this ceaseless change affect an object; it either becomes more complex or more simple; it moves forward or backward; it grows or decays. In the words of Spencer, "All things are growing or decaying, accumulating matter or wearing away, integrating or disintegrating."[A] This, then, is the greatest known fundamental law of the universe, and of all things in it--that nothing stands still, but either progresses (evolution), or retrogrades (dissolution). Now, it has been found that under normal conditions all things undergo a process of evolution; that is, become more complex, or advance.[B] This, in its essence, is the law of evolution, about which so much has been said during the last fifty years. Undoubtedly, this law is correct, and in harmony with the known facts of the universe. It certainly throws a flood of light upon the phenomena of nature; though of itself, it tells little of the force behind it, in obedience to which it operates. [Footnote A: Loc. cit., p. 292.] [Footnote B: Loc. cit., p. 337.]