Commentaries on Porphyry’s Isagoge
Two commentaries explain Porphyry’s introduction to Aristotle’s Categories and its five predicables: genus, species, difference, property and accident. The second takes up the questions Porphyry left unanswered, whether genera and species exist in reality or only in thought, and so opened the long medieval debate on universals.
Understanding the text
The first commentary, a dialogue in two books, follows the Latin translation of Marius Victorinus; the second, in five books, rests on Boethius’s own new translation. Both belong to the early years of his programme, roughly between 500 and 510, and became standard schoolbooks of the old logic.
Key points
- 01
Predicables
Genus, species, difference, property and accident classify the ways in which one term can be said of another.
- 02
Three questions
Porphyry asks whether genera and species subsist or lie in thought alone, whether they are bodily or incorporeal, and whether they are separate or in sensible things.
- 03
Abstraction
Universals subsist in sensible things but are understood apart from bodies; Boethius presents this Aristotelian answer without deciding against Plato.
Explore the ideas in depth
The question of universals
Reconstruct Porphyry’s three questions and the answer Boethius gives them in his second commentary on the Isagoge.
Situating the text
The first commentary, a dialogue in two books, follows the Latin translation of Marius Victorinus; the second, in five books, rests on Boethius’s own new translation. Both belong to the early years of his programme, roughly between 500 and 510, and became standard schoolbooks of the old logic. Two commentaries explain Porphyry’s introduction to Aristotle’s Categories and its five predicables: genus, species, difference, property and accident. The second takes up the questions Porphyry left unanswered, whether genera and species exist in reality or only in thought, and so opened the long medieval debate on universals.
Following the arguments
Predicables : Genus, species, difference, property and accident classify the ways in which one term can be said of another. Three questions : Porphyry asks whether genera and species subsist or lie in thought alone, whether they are bodily or incorporeal, and whether they are separate or in sensible things. Abstraction : Universals subsist in sensible things but are understood apart from bodies; Boethius presents this Aristotelian answer without deciding against Plato.
Continuing the reading
Read chapters 10 and 11 of the first book of the second commentary, where the three questions are answered, alongside Porphyry’s own short preface. The first commentary, a dialogue in two books, follows the Latin translation of Marius Victorinus; the second, in five books, rests on Boethius’s own new translation. Both belong to the early years of his programme, roughly between 500 and 510, and became standard schoolbooks of the old logic.
Questions to carry into your reading
- Why does Boethius hold that a universal understood apart from bodies is not a false thought?
- Where does he refrain from choosing between Plato and Aristotle, and for what reason?
Abstraction lets the mind consider separately what exists only together, without falsifying what it understands.
How to read it
Read chapters 10 and 11 of the first book of the second commentary, where the three questions are answered, alongside Porphyry’s own short preface.
Editions & sources
Summaries and key points are original editorial interpretations. They accompany reading the work and do not replace an edition of the text. Editorial method ↗