For knowing is spoken of in three ways: it may be either universal knowledge or knowledge proper to the matter in hand or actualising such knowledge; consequently three kinds of error also are possible.
And why are you so firmly, so triumphantly, convinced that only the normal and the positive--in other words, only what is conducive to welfare--is for the advantage of man? Is not reason in error as regards advantage? Does not man, perhaps, love something besides well-being? Perhaps he is just as fond of suffering? Perhaps suffering is just as great a benefit to him as well-being? Man is sometimes extraordinarily, passionately, in love with suffering, and that is a fact.
Zarathustra was the first to consider the fight of good and evil the very wheel in the machinery of things: the transposition of morality into the metaphysical realm, as a force, cause, and end in itself, is his work. [...] Zarathustra created this most calamitous error, morality; consequently, he must also be the first to recognize it.
Those who assert that the mathematical sciences say nothing of the beautiful or the good are in error. For these sciences say and prove a great deal about them; if they do not expressly mention them, but prove attributes which are their results or definitions, it is not true that they tell us nothing about them. The chief forms of beauty are order and symmetry and definiteness, which the mathematical sciences demonstrate in a special degree.
The fossil record implies trial and error, an inability to anticipate the future, features inconsistent with an efficient Great Designer (although not with a Designer of a more remote and indirect temperament)
Understand that for every rule which I have mentioned from the Quran, the Devil has one to match it, which he puts beside the proper rule to cause error.
Were half the power that fills the world with terror, Were half the wealth bestowed on camps and courts, Given to redeem the human mind from error, There were no need of arsenals or forts.
If at times I have thought myself unfortunate, it is because of a confusion, an error. I have mistaken myself for someone else... Who am I really? I am the author of The World as Will and Representation, I am the one who has given an answer to the mystery of Being that will occupy the thinkers of future centuries. That is what I am, and who can dispute it in the years of life that still remain for me?