His famous Introduction to the Categories of Aristotle was a corner-stone of the early mediaeval knowledge of logic. He wrote a keenly rational work against the Christians, in which his critical acumen pointed out that the Book of Daniel was not composed before the reign of Antiochus Epiphanes. He did much to render intelligible the writings of his master Plotinus, and made a compend of Neo-Platonism in the form of Sentences. These survive, as well as his work on Abstinence from Eating Flesh, and other treatises, allegorical and philosophic.
He was to Plotinus as Soul, in the Neo-Platonic system, was to Mind—Soul which somehow was darkly, passionately tangled in the body of which it was the living principle. The individual soul of Porphyry wrestled with all the matters which the mind of Plotinus made slight account of. Plotinus lived aloof in a region of metaphysics warmed with occasional ecstasy. Porphyry, willy nilly, was drawn down to life, and suffered all the pain of keen mentality when limed and netted with the anxieties of common superstitions. He was forever groping in a murky atmosphere. He could not clear himself of credulity, deny and argue as he might. Nor could asceticism pacify his mind. Philosophically he followed Plotinus's teachings, and understood them too, which was a marvel. Many of his own, or possibly reflected, thoughts are excellent. No Christian could hold a more spiritual conception of sacrifice than Porphyry when thinking of the worship of the Mind—the Nous or Second God. Offer to it silence and chaste thought, which will unite us to it, and make us like itself. The perfect sacrifice is to disengage the soul from passions.[1] What could be finer? And again says Porphyry: The body is the soul's garment, to be laid aside; the wise man needs only God; evil spirits have no power over a pure soul. But, but, but—at his last statement Porphyry's confidence breaks. He is worried because it is so hard to know the good from evil demons; and the latter throng the temples, and must be exorcised before the true God will appear. This same man had said that God's true temple was the wise man's soul! Alas! Porphyry's nature reeks with contradictions. His letter to the Egyptian priest,
- ↑ De abstinentia, ii. 34.
