INTRODUCTION

The time at which Boethius wrote was not a great one in the history of logic and he himself was certainly not a great logician. His importance lies rather in acting as an intermediary between the logicians of antiquity and the those of the Middle Ages. With his translations, commentaries and independent logical works Boethius provided mediaeval philosophers with most of what they knew about ancient logic and so with the foundations upon which mediaeval logic was built. The most important parts of those foundations were the metaphysics of substance and semantics of common names which could be extracted from Boethius' commentaries on the Isagoge, Categories, and De interpretatione, his account of conditional propositions in De hypotheticis syllogismis, and his treatment of topical argumentation in De topicis differentiis. Boethius' own peculiar contribution to the history of logic was an exposition of the hypothetical syllogism which, for the reasons we will consider here, would play no role in the development of logic after the middle of the twelfth century.

INHERENCE AND INSEPARABILITY

In his commentaries Boethius provided the Middle Ages with their first acquaintance, in a much simplified form, with the distinctions first drawn by Aristotle between per se and per accidens inherence and between two kinds of inseparability which would be crucial for the later development of logic.

Porphyry offers the Isagoge to his readers as an account of what needs to be known about the predicables, i.e. genus, species, differentia, property and accident, by someone setting out to study Aristotle’s theory of the ten predicaments, or categories.