Handbook of the History of Logic: - Fordham University Faculty

The Latin Tradition of Logic to 1100 41
the end of his time as a schoolmaster. If so, then his curriculum seems, then, to
have been a fully Boethian one, close to what would be the norm in the twelfth
century, though with a few peculiarities, such as the use of Victorinus’s translation
of the Isagoge (a sign, perhaps, that it was the first of Boethius’s two commentaries
on the work Gerbert turned to). There is no earlier mention of a medieval
logician teaching using all of Boethius’s monographs (and the treatise on definition
by Victorinus, usually misattributed to Boethius), though it is striking that
Cicero’s Topics with Boethius’s commentary (available since the ninth century) is
mentioned in first place, and the De topicis differentiis, which would become the
main textbook, only afterwards.
No records of Gerbert’s lectures on Porphyry, Aristotle and Boethius survive.
His one logical work is a short treatise called De rationale et ratione uti [Gerbert,
1867, 297-310], that is to say, a discussion of the meaning of the terms ‘rational’
and ‘to use reason’ as used by Porphyry when he discusses what features genera
and differentiae have in common. The point at issue was that, when we say
‘What is rational uses reason’, an apparently true proposition, we seem to be
saying something false, since not everything that is rational is actually its reason.
The basis of the problem is an ambiguity of the kind that could lie at the basis
of the sort of sophisms which twelfth-century and which later logicians enjoyed
unravelling. Gerbert’s approach is less direct, but he succeeds in showing up the
logical inadequacies of those contemporaries who had raised this difficulty and
showing off his own knowledge of Boethius commentaries on the Isagoge and On
Interpretation.
4.3 Abbo of Fleury
([Van de Vyver, 1935; Abbo of Fleury, 1997: Einleitung; Schupp, 2004])
Abbo led a far quieter life than Gerbert, mostly at the monastery of Fleury, which
he entered shortly after his birth in c. 945. He studied in Paris and Rheims, and
spent a short period in England (985-7); in 988 he became Abbot of Fleury. His
logical work was therefore probably done in the 970s and early 980s, at much the
same time as Gerbert’s.
Although there is no explicit record, as in Gerbert’s case, that Abbo taught
the whole Boethian logical curriculum, the manuscript evidence suggests that he
at least knew the range of Boethius’s monographs, since the earliest manuscript
which contains the treatises, mentioned above, also contains Abbo’s works on
categorical and hypothetical syllogisms and was written at Fleury in his lifetime.
These two treatises are themselves the very best illustrations of the change in the
curriculum, since each looks both backwards to the mainly non-Boethian sources
that had been dominant, and forward, by basing itself to a great extent on Boethius
and Aristotle. So, in the treatise on categorical syllogisms [Abbo of Fleury, 1966,
1-64], he uses mainly On Interpretation and Boethius’s commentaries, but he
also draws on Apuleius, and he explicitly compares the two sources, putting their
squares of opposition and their moods of the syllogism side by side. Abbo is