Handbook of the History of Logic: - Fordham University Faculty

The Latin Tradition of Logic to 1100 3
here are titled, not ‘On Logic’ but ‘On Dialectic’, and the logicians treated here
often referred to themselves as ‘dialecticians’ (dialectici) rather than ‘logicians’.
There certainly was a distinction that could be made, and was in some contexts,
between ‘logic’ and ‘dialectic’ in which ‘logic’ stands for the study of demonstrative
reasoning (and so the Analytics), and ‘dialectic’ for persuasive reasoning (and so
the Topics). Usually, however, in the period until 1100, the words were used
interchangeably, with ‘dialectic’ as the more common, to cover the whole of logic.
In what follows, I shall speak simply of ‘logic’, although the word used in the
sources will often be dialectica. (For a rather different view, see [D’Onofrio, 1986]).
2.1 Before Boethius
The Latin logical works from before Boethius’s time divide into two groups: there
are Cicero’s Topics, Apuleius’s Peri Hermeneias, Marius Victorinus’s On Definition
and Book IV of Martianus Capella’s On the Marriage of Mercury and
Philology, all of which have various links with each other, as will become clear,
although they also, except for Martianus, provide independent glimpses of Greek
logic. There is also the Ten Categories, which unrelated to these other Latin works.
Cicero ([Huby, 1989; Long, 1995])
The earliest Latin logical text is also treatise in legal rhetoric. Cicero wrote his
Topics (‘Topica’) [Cicero, 1924] in 44 BC, and professes that he will explain there
to his friend Trebatius the doctrine of Aristotle’s Topics. In fact, the work reflects
the Rhetoric as much as the Topics, and probably handbooks of rhetorical and
Peripatetic doctrine even more [Long, 1995, 54-7; Stump, 1989, 57-66]. The subject
of the Topics is said to be the finding of arguments; as his examples show, Cicero
has in mind particularly the needs of an orator in the courts. The aim of argument
is seen in terms of its persuasive effect: it convinces someone of something that was
in doubt (§ 8). The tools for finding arguments are, as in Aristotle, the topics or
loci. But whereas Aristotle’s topics are a proliferation of argumentative strategies,
linked to his doctrine of the Categories, Cicero’s topics are a short list of types of
relationships, consideration of which can help the orator to discover an argument.
They include, for instance, genus, species, likeness, cause, effect, comparison. For
instance, if the orator needs to show that the heir to a dilapidated house is not
bound to repair it, he can argue that the case is similar to that of an heir to a
slave, who is not bound to replace him if he has died (§15). All these topics and
arguments are intrinsic, but the orator can also argue extrinsically, says, Cicero, by
appealing to authority. The importance for logic of this very practically-oriented,
rhetorically directed treatise lies in the evidence it gives of how Aristotle’s theory
of topics had been changed in later centuries, and in the use that Boethius would
make of it.
For historians of logic, the most important passage in the book is where (§§53-
7) Cicero sets out the modi dialecticorum — which consist of an extended and
slightly mangled list of the Stoic indemonstrables, expressed, not as the Stoics did,