What we know is not capable of being otherwise; of things capable of being otherwise we do not know, when they have passed outsideour observation, whether they exist or not. Therefore the object of knowledge is of necessity. Therefore it is eternal; for things that are of necessity in the unqualified sense are all eternal; and things that are eternal are ungenerated and imperishable.
AristotleBut then in what way are things called good? They do not seem to be like the things that only chance to have the same name. Are goods one then by being derived from one good or by all contributing to one good, or are they rather one by analogy? Certainly as sight is in the body, so is reason in the soul, and so on in other cases.
AristotleAccordingly, the poet should prefer probable impossibilities to improbable possibilities. The tragic plot must not be composed of irrational parts.
Aristotle