Speculative reflection has taken the place of religious imagination. The advance consists in this, namely, that energies or ideas indicate a greater degree of uniformity and invariability than was to be expected of deities and spirits. But the metaphysical stage is still predominantly negative and critical. It destroys the authorities and yet fails to attain to a new basis of certitude. It is the period of individualism.
At the positive stage both imagination and reflection are subordinated to experience. The only criterion of truth consists of the agreement with the facts. Positivism does not however permit the facts to remain in isolation; it seeks after the laws, i.e., the constant relations of the phenomena. Science builds on the invariability of natural law, which was anticipated already by the Greeks, but clearly expressed in modern times by Bacon, Galileo and Descartes, the real founders of positive philosophy.—It is impossible to refer the numerous laws to a single law. Our knowledge cannot attain objective unity,—unity is only subjective. Subjective unity consists in the fact that the same method—the explanation of facts by facts—is consistently applied everywhere. This unity of method furnishes a basis for the fellowship of minds, which has not existed since the Middle Ages.
The point of difference between these stages is partly due to the difference in the range of experience, partly to the different viewpoints which are postulated in the explanation of nature. Before this explanation could be found in the facts themselves it was necessary to postulate imagination and speculation in the interpretation of nature.
b. The classification of the sciences coincides with the theory of the three stages. It rests first of all upon the
