Nicene and Post-Nicene Fathers, Vol. IV:
Writings in Connection with the Manichæan Controversy.: Chapter 20

Chapter 20.—Refutation of the Absurd Idea of Two Territories.

22.  But perhaps, instead of thus addressing carnal minds, we should rather descend to the views of those who either dare not or are as yet unfit to turn from the consideration of material things to the study of an immaterial and spiritual nature, and who thus are unable to reflect upon their own power of reflection, so as to see how it forms a judgment of material extension without itself possessing it.  Let us descend then to these material ideas, and let us ask in what direction, and on what border of the shining and sacred territory, to use the expressions of Manichæus, was the region of darkness?  For he speaks of one direction and border, without saying which, whether the right or the left.  In any case, it is clear that to speak of one side implies that there is another.  But where there are three or more sides, either the figure is bounded in all directions, or if it extends infinitely in one direction, still it must be limited in the directions where it has sides.  If,then, on one side of the region of light there was the race of darkness, what bounded it on the other side or sides?  The Manichæans say nothing in reply to this; but when pressed, they say that on the other sides the region of light, as they call it, is infinite, that is, extends throughout boundless space.  They do not see, what is plain to the dullest understanding, that in that case there could be no sides?  For the sides are where it is bounded.  What, then, he says, though there are no sides?  But what you said of one direction or side, implied of necessity the existence of another direction and side, or other directions and sides.  For if there was only one side, you should have said, on the side, not on one side; as in reference to our body we say properly, By one eye, because there is another; or on one breast, because there is another.  But if we spoke of a thing as being on one nose, or one navel, we should be ridiculed by learned and unlearned, since there is only one.  But I do not insist on words, for you may have used one in the sense of the only one.