Porphyry

Works

• c. 270Isagoge (Introduction)

  A short introduction to Aristotle’s Categories on genus, species, difference, property and accident – it opens by asking whether genera and species really exist, and declines to answer.

• c. 275On Abstinence from Killing Animals

  Four books to a friend who had gone back to eating meat: animals have a share of reason, justice extends to them, and the philosopher should give up meat and blood sacrifice.

Position

Porphyry’s influence rests less on original doctrine than on the forms in which he passed on Plato and Aristotle. In the Isagoge, a short introduction to Aristotle’s Categories, he explained five terms: genus, species, difference, property and accident. At the outset he named three questions he would leave aside – whether genera and species exist or are only in the mind; if they exist, whether they are bodies or incorporeal; and whether they are separate from sensible things or in them. Through Boethius’ translation and two commentaries these questions became the medieval problem of universals, and Abelard still wrote his logic as glosses on Porphyry. The Isagoge was translated into Syriac and Arabic and opened the logical curriculum there as well: al-Farabi commented on it, and Avicenna began the logic of his Book of Healing with an Introduction (al-Madkhal) modelled on it. Porphyry held that Aristotle’s logic was compatible with Plato’s metaphysics, and his commentaries made Aristotle a fixed part of Platonist teaching. On Abstinence argues that animals have perception, memory and a share of reason, that justice extends to them, and that a philosopher who seeks to free the soul from the body should give up meat and blood sacrifice. Against the Christians, in fifteen books, examined the Bible philologically; it argued, for example, that the Book of Daniel was written in the second century BCE, not during the Exile. Christian emperors ordered it burned, and only fragments quoted by its opponents survive. Augustine called Porphyry “the most learned of the philosophers” and in The City of God argued at length against his teaching on the soul’s return to God. Avicenna, in turn, attacked the doctrine he ascribed to Porphyry that the intellect becomes identical with what it knows.

Life & context

Porphyry was born in Tyre in Phoenicia, probably in 234 CE; his Phoenician name was Malchus, “king”. He studied in Athens with the critic and Platonist Longinus and in 263 came to Rome to join the circle of Plotinus. Five years later, deeply depressed – he tells us that Plotinus noticed he was thinking of suicide – he followed his teacher’s advice and went to Sicily, where he still was when Plotinus died in 270. He later taught in Rome. Late in life he married Marcella, a widow with seven children, and addressed to her a letter of philosophical exhortation. Around 301 he published Plotinus’ treatises in six groups of nine, the Enneads, prefaced by a Life of Plotinus. He died around 305. He wrote some sixty works, of which only a few survive complete.

Further main works

• Commentary on the Categories (in question-and-answer form)
• On the Cave of the Nymphs in the Odyssey
• Sentences Leading to the Intelligibles (Aphormai)
• Letter to Marcella
• Against the Christians (fragments)
• Life of Plotinus and edition of the Enneads (c. 301)