Friedrich Nietzsche, Beyond Good and Evil: Prelude to a Philosophy of the Future, Chapter 1, Aphorism 4, Circa 1907, Translated by Helen Zimmern, 2007 by Barnes & Noble, Inc.

The falseness of an opinion is not of us any objection to it: it is here, perhaps, that our new language sounds most strangely. The question is, how far an opinion is life-furthering, life-preserving, species-preserving, perhaps species-rearing; and we are fundamentally inclined to maintain that the falsest opinions (to which the synthetic judgments a priori belong), are the most indispensable to us; that without a recognition of logical fictions, without a comparison of reality with the purely imagined world of the absolute and immutable, without a constant counterfeiting of the world by means of numbers, man could not live – that the renunciation of false opinions would be a renunciation of life, a negation of life. To recognize untruth as a condition of life: that is certainly to impugn the traditional ideas of value in a dangerous manner, and a philosophy which ventures to do so, has thereby alone placed itself beyond good and evil.