“Probable impossibilities are to be preferred to improbable possibilities.”

“Accordingly, the poet should prefer probable impossibilities to improbable possibilities.”

“With respect to the requirement of art, the probable impossible is always preferable to the improbable possible.”

“The poet's function is to describe, not the thing that has happened, but a kind of thing that might happen, i.e., what is possible as being probable or necessary...Hence poetry is something more philosophic and of graver import than history, since its statements are of the nature rather of universals, whereas those of history are singulars.”

“For what is the best choice, for each individual is the highest it is possible for him to achieve.”

“We must not listen to those who advise us 'being men to think human thoughts, and being mortal to think mortal thoughts' but must put on immortality as much as possible and strain every nerve to live according to that best part of us, which, being small in bulk, yet much more in its power and honour surpasses all else.”

“And further, observing that all this indeterminate substance is in motion, and that no true predication can be made of that which changes, they supposed that it is impossible to make any true statement about that which is in all ways and entirely changeable. For it was from this supposition that there blossomed forth the most extreme view of those which we have mentioned, that of the professed followers of Heraclitus, and such as Cratylus held, who ended by thinking that one need not say anything, and only moved his finger; and who criticized Heraclitus for saying that one cannot enter the same river twice, for he himself held that it cannot be done even once.”