My former treatise, O Theodotus, was intended to prove that every wicked man was a slave, and that proposition I fully established by many natural and unquestionable arguments; and this other treatise is akin to that one, being its full brother both by the father’s and the mother’s side, and being even, in some sort, a twin with it, since in it we will proceed to show that every virtuous man is free.

Now it is said, that the most sacred sect of the Pythagoreans, among many other excellent doctrines, taught this one also, that it was not well to proceed by the plain ordinary roads, not meaning to urge us to walk among precipices (for it was not their object to weary our feet with labour), but intimating, by a figurative mode of speech, that we ought not, either in respect of our words or actions, to use only such as are ordinary and unchanged;

and all men who have studied philosophy in a genuine spirit, showing themselves obedient to this injunction, have looked upon it as a sentence, or rather as a law of equal weight with a divine oracle; and, departing from the common opinions of men, they have cut out for themselves a new and hitherto untravelled path, inaccessible to such as have no experience of wise maxims and doctrines, building up systems of ideas, which no one who is not pure either may or can handle.

Now when I speak of men not being pure, I mean those who have either been utterly destitute of education, or else who have tasted of it obliquely, and not in a straight-forward manner, changing the stamp of the beauty of wisdom so as to give an impression of the unsightliness of sophistry.

These men, not being able to discern that light which is appreciable only by the intellect, by reason of the weakness of the eyes of their soul, which are by nature easily dazzled by too much brightness, like men living in night and darkness, do not believe those who live in the light of day, and regard everything which they speak of as having seen them most distinctly through the beams of the sun shining powerfully upon them, as prodigious pictures, like so many visions or dreams, in no respect different from the exhibitions of jugglers;