cphil_class

Porphyry was a Neoplatonic philosopher, who was born in Tyre in A.D. 232 or 233. He studied in Athens under Longinus, and then in Rome under Plotinus, becoming his disciple. He collected the writings of Plotinus, into six volumes, called the Enneads. Porphyry wrote many works whose purpose was the preparation of the soul for union with the One. He wrote a book against the Christians which was burned by the order of Theodosius II in A.D. 435. Porphyry died in A.D. 304. Porphyry added “species” to Aristotle’s list of four predicables. For Aristotle a predicable was a type of predicate which may be affirmed or denied of a subject in a logical proposition. In Aristotle’s logic there are four predicables that could be obtain when a universal term is predicated to a subject: genus, specific difference (differentia), property, and contingent accident. Aristotle did not identify “species” as a predicable, although he used the term in his discussion of predicables. Porphyry included “species” in his list of predicables. But Porphyry is best known for his illustrative diagram relating genus, species, and individuals, called the Tree of Porphyry (Arbor Porphyrii). Taking the category of substance as his example, Porphyry diagrammed the relationship between this basic category, which is a genus and not a species, and those terms of lesser generality which are both genus and species. The differentiae controls these terms, down to the most limited species which contains only individuals as its members. To the right in the diagram there is shown the complements of the differential terms. Porphyry seems to have combined Plato’s method of division with Aristotle’s theory of predicables. The tree came into Latin literature through the translation of Boethius, and had great influence during the Middle Ages. Porphyry suggests that it is beyond the power of man to know whether genus and species are subsistent entities or exist only as concepts, raising the problem of universals.