27. In reference to your alternate praise and disparagement of me, you argue with great acuteness that you have the same right to speak good and evil of me that I have to find fault with Origen and Didymus whom I once praised. I must instruct you, then, wisest of men and chief of Roman dialecticians, that there is no fault of logic in praising a man in certain respects while you blame him in others, but only in approving and disapproving one and the same thing. I will take an example, so that, though you may not understand, the wise reader may join me in understanding the point. In the case of Tertullian we praise his great talent, but we condemn his heresy. In that of Origen we admire his knowledge of the Scriptures, but nevertheless we do not accept his false doctrine. As to Didymus, however, we extol both his powers of memory, and the purity of his faith in the Trinity, while on the other point in which he erred in trusting to Origen we withdraw from him. The vices of our teachers are not to be imitated, their virtues are. There was a man at Rome who had an African, a very learned man, as his grammar teacher; and he thought that he was rising to an equality with his teacher because he copied his strident voice and his faulty pronunciation. You in your Preface to the Περὶ ᾽Αρχῶν speak of me as your brother and call me your most eloquent colleague, and proclaim my soundness in the faith. From these three points you cannot draw back; carp at me on all other points as you please, so long as you do not openly contradict this testimony which you bear to me; for in calling me friend and colleague, you confess me worthy of your friendship; when you proclaim me an eloquent man, you cannot go on accusing me of ignorance; and when you confess that I am in all points a catholic, you cannot fix on me the guilt of heresy. Beyond these three points you may charge me with anything you like without openly contradicting yourself. From all this calculation the net result is that you are wrong in blaming in me what you formerly praised; but that I am not in fault when, in the case of the same men, I praise what is laudable and blame what is censurable.