"Truth" is the will to be master over the manifold sensations that reach consciousness; it is the will to classify phenomena according to definite categories. In this way we start out with a belief in the "true nature" of things (we regard phenomena as real).
The character of the world in the process of Becoming is not susceptible of formulation; it is "false" and "contradicts itself." Knowledge and the process of evolution exclude each other. Consequently, knowledge must be something else; it must be preceded by a will to make things knowable, a kind of Becoming in itself must create the impression of Being. 33-34
The chief error of psychologists: they regard the indistinct idea as of a lower kind than the distinct; but that which keeps at a distance from our consciousness and which is therefore obscure, may on that very account be quite clear in itself. The fact that a thing becomes obscure is a question of the perspective of consciousness. 42
The criterion of truth lies in the enhancement of the feeling of power. 49
Logic was intended to be a method of facilitating thought: a means of expression,—not truth.... Later on it got to act like truth.... 50
In a world which was essentially false, truthfulness would be an anti-natural tendency: its only purpose would be to provide a means of attaining to a higher degree of falsity. 51
We have absolutely no experience concerning cause; viewed psychologically we derive the whole concept from the subjective conviction, that we ourselves are causes. 55
"Truth" is not something which is present and which has to be found and discovered; it is something which has to be created and which gives its name to a process, or, better still, to the Will to overpower, which in itself has no purpose.... 60
The absolute is even an absurd concept: an "absolute mode of existence" is nonsense, the concept "being," "thing," is always relative to us.
The trouble is that, owing to the old antithesis "apparent" and "real," the correlative valuations "little value" and "absolute value" have been spread abroad. 83