The understanding of the method of science, the understanding of the mind, is destined to solve all the problems of religion and philosophy, to explain thoroughly all the great and small riddles, and thus fully to restore research to its mission of empirically studying details. If we are aware that it is a law of reason to require some perceptible material, some cause, for its operation, then the question regarding the first or general cause becomes superfluous. Human understanding is then seen to be first and last cause of all concrete causes. If we understand that it is a law of reason to require for its operation some given object, some beginning at which to start, then the question of the first beginning must necessarily become inane. If we understand that reason derives abstract units out of concrete multiplicities, that it constructs truth out of phenomena, substance out of attributes, that it perceives all things as parts of a whole, as individuals of some genus, as qualities of some object, then the question regarding a "thing itself," a something which in reality is back of all things, must needs become irrelevant. In brief, the understanding of the interdependence of reason reveals the unreasonableness of the demand for independent reason. Now, although the main object of metaphysics, the cause of all causes, the beginning of all beginnings, the nature of things, causes little inconvenience to modern science, and even though the needs of the present have overcome the leaning for speculation, this practical downfall of speculation does not suffice for the solution of its problems. So long as the theoretical law is not understood, according to which reason requires some concrete object for its operation, there is no hope of abandoning objectless thought, this malpractice of speculative philosophy, which pretends to generate knowledge without intercourse with objective reality. Our naturalists demonstrate this very clearly as soon as they turn from their tangible specialties to abstract things. The dispute over questions of life's wisdom, of morality, or the quarrel over the wise, good, right, or bad, reveals that here is the boundary of scientific agreement. The scientific explorers of the exact sciences abandon every day their inductive method when dealing with social problems, and stray off into the regions of speculative philosophy. Just as in physics they believe in imperceptible physical truths, in "things themselves," so in social matters they believe in the reasonable, wise, right, or bad, in the sense of "things themselves," of absolute phases of life, of unconditional conditions. It is here where the outcome of our studies, of the critique of pure reason, must be applied.