“Knowledge becomes evil if the aim be not virtuous.”

“[On the virtuous man] "He combines the highest, lowest and middle chords in complete harmony within himself.”

“A library of wisdom, is more precious than all wealth, and all things that are desirable cannot be compared to it. Whoever therefore claims to be zealous of truth, of happiness, of wisdom or knowledge, must become a lover of books.”

“I must go beyond the dark world of sense information to the clear brilliance of the sunlight of the outside world. Once done, it becomes my duty to go back to the cave in order to illuminate the minds of those imprisoned in the 'darkness' of sensory knowledge.”

“Knowledge unqualified is knowledge simply of something learned.”

“False words are not only evil in themselves, but they infect the soul with evil.”

“The evil never attains to any real friendship, either with good or evil.”