For such is man: a Theological Dogma might be refuted to him a thousand times - provided however, that he had need of it, he would again and again accept it as true. Belief is always most desired, most pressingly needed where there is a lack of will. Fanaticism is the sole "volitional strength" to which the weak and irresolute can be excited, as a sort of hypnotising of the entire sensory-intellectual system.
Friedrich NietzscheLogic, too, also rests on assumptions that do not correspond to anything in the real world, e.g., on the assumption that there areequal things, that the same thing is identical at different points in time: but this science arose as a result of the opposite belief (that such things actually exist in the real world). And it is the same with mathematics, which would certainly never have arisen if it had been understood from the beginning that there is no such thing in nature as a perfectly straight line, a true circle, and absolute measure.
Friedrich Nietzsche