Handbook of the History of Logic: - Fordham University Faculty

The Latin Tradition of Logic to 1100 5
on logic in Latin. Two of his logical works survive: a translation of Porphyry’s
Isagoge (used by Boethius for his first commentary) [Hadot, 1971, 371-80] and On
Definition (De definitione/definitionibus [Hadot, 1971, 331-62] that was wrongly
attributed to Boethius in the Middle Ages. Victorinus also wrote a now lost
commentary on Cicero’s Topics (Reconstruction in [Hadot, 1971, 118-41]), which
is mentioned critically by Boethius in his own commentary on the same work, and
from Cassiodorus we know that he wrote, just as Boethius would do, a treatise on
hypothetical syllogisms. (See [Hadot, 1971, 323-7] for an assemblage of possible
traces of the treatise.) According to Cassiodorus, Victorinus also translated the
Categories and On Interpretation and wrote a long commentary on it. But there
is no trace of these works, and it has been argued that Cassiodorus (whose text
presents problems: see below, subsection 2.3, pages 21–22) is misleading here
[Hadot, 1971, 105-8].
Victorinus placed logic within the framework of rhetoric. Study of the Isagoge,
Categories and On Interpretation led, not as in the Aristotelian organon, primarily
to syllogistic (in the Prior Analytics) and its use in demonstration (in the Posterior
Analytics), but to the topics, as expounded by Cicero. And, for Victorinus — to
judge from his words as probably reported by Cassiodorus [Cassiodorus, 1937, 127]
— it is the very fact that the Ciceronian topics presents arguments that are suited,
not just to philosophers, but to orators, lawyers and poets as well, which makes
them so precious. On Definition and the (lost) treatise on hypothetical syllogisms
can be seen as continuations of the commentary on Cicero’s Topics, since each
corresponds to a part of Cicero’s text (definition: §§26-37; hypothetical syllogisms
53-7) not treated in the commentary itself, which covers only half the work. On
Definition draws extensively on Cicero himself in categorizing and explaining the
different sorts of definition — rhetorical definition, philosophical definition (which
is based on the five predicables: genus, species, differentia, proprium — i.e. an
accident that distinguishes a species, such as ability to laugh in humans — and
accident) and other types of definition, such as that from a thing’s parts, which
does not explain what the things are, but gives some understanding of them. It has
been suggested that here a work by Porphyry may have been the source. [Hadot,
1968, I, 482-8]
The ‘Ten Categories’ ([Kenny, 2005, 128-33])
The Categorial Decem(Ten Categories), as it came to be called, probably owed
some of its early medieval popularity to the fact that it came to be attributed to
Augustine. But it also deserved to be used, because it is an excellent work for
beginners in logic trying to understand Aristotle. The real author is unknown,
but in a couple of comments (Aristotle, 1961, 137:20-1; 175:18-9) he makes clear
that he belongs to the circle of Themistius, the fourth-century philosopher and
statesman who was perhaps the last member of the ancient Peripatetic school.
(Anthony Kenny has suggested that the author of the paraphrase might in fact be
Marius Victorinus: [Kenny, 2005, 130-3].)
The paraphraser reveals his approach when (Aristotle, 1961, 148:33 — 149:2),