On Fugitives (187-189)

And when they have come to the gates of virtue, the preliminary liberal sciences, and have seen the fountains, and the stems of the palm-trees growing by them, they are said to pitch their tents, not by the palm-trees, but by the waters. Why is this? Because those who carry off the prizes of perfect virtue are adorned with palm-leaves and with fillets; but those who are still exercising themselves in the preliminary branches of instruction, as people thirsting for learning, settle [*] [*]

Such then are the fountains of intermediate instruction. Let us now consider the fountain of folly, concerning which the lawgiver speaks thus, "Whosoever shall lie with a woman who is sitting apart has uncovered her fountain, and she has uncovered the issue of her blood; they shall both be destroyed." [*] He here calls the external sense a woman, representing the mind as her husband.

When therefore the woman, having forsaken her legitimate husband, settles near those objects of the external sense which allures and destroys, and embraces them all in an amorous manner; then therefore, if the mind be turned to sleep when it is necessary that it should be awakened, it has uncovered the fountain of the external sense, that is itself, that is to say, it has rendered itself, without a covering and without a wall, and easy to be plotted against.