VII. Are There Limits to Knowledge?

Inductive inference is the methodical foundation of modern metaphysical realism. At one time it was believed that out of concepts could be evolved something that is no longer a concept. It was believed that from concepts could be derived the metaphysical realities which of necessity, metaphysical realism must have. This kind of philosophizing is now superseded. Instead, it is believed that from a sufficiently large number of perceptual facts one can infer the character of the thing-in-itself which underlies these facts. Just as in the past one tried to derive the metaphysical from concepts, so to-day one tries to derive it from perceptions. As concepts are transparent in their clarity, it was believed that one could also deduce the metaphysical from them with absolute certainty. Perceptions are not of such transparency. Each later perception is always a little different from those of the same kind that preceded it. Therefore, anything inferred from the earlier perception is, in reality, somewhat modified by each following one. The aspect of the metaphysical arrived at in this way, therefore, can be said to be only relatively correct, for it is subject to correction by future instances. Eduard von Hartmann's metaphysics is of a kind that is determined by this methodical principle. This is expressed in the motto he gave on the title-page of his first major work: “Speculative results according to the inductive method of natural science.”