I. (1) 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. (2) 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 talk 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; (3) 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. (4) 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. (5) 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 been 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; (6) for how can it be anything but a complete marvel and absurdity to call those men exiles, who do not only live in the middle of the city, but who even take a part in the councils, and courts of justice, and public assemblies, and who, at times, fulfil the duties of clerks of the market, and of superintendants of gymnastic games, and of other offices of different kinds; (7) and, on the other hand, to call those men citizens who have either never been enrolled as such at all, or else have had sentences of infamy or of banishment pronounced against them; men who have been driven beyond the boundaries of the land, and who are unable, not only to set foot upon the country, but even to behold their native soil from a distance, unless they are urged on by some insane frenzy to rush upon certain death; for there are innumerable persons to detect and to punish all those who return from banishment, being both sharpened by their own feelings, and acting in obedience to the commands of the laws.