Manlii Seuerini Boetii, Opera omnia, accurante J.-P. Migne, tomus posterior, Parisiis 1891, 1173-1216 (Patrologiae Latinae, 64)
The De differentiis topicis is the last extant treatise on logic that Boethius wrote. It was probably completed before 523 AD, being composed shortly after his commentary on Cicero’s Topica (De Rijk 1964). The work, which is characterized by a high degree of systematization, seeks to discover a method for finding arguments that can be used to resolve any type of quaestio. Aristotle first devised a theory about this discipline in the Topics, arguing that it was the technique of correctly building a dialectic dispute; indeed, he defined the function of a topos as guaranteeing the validity of an argument by bringing it back to a universal point-of-view (Pinborg 1984). Cicero was the chief theorist of topica in the Latin world, but his studies were directed almost exclusively at rhetorical ends (Riposati 1947).
Before writing this treatise, Boethius had translated and glossed Aristotle’s Topics (regrettably, his commentary has not survived) and also commented on Cicero’s Topica. In the present work, he tries to harmonize Greek and Roman teaching while casting light on the original dialectic value of Cicero’s Topica (De. diff. top. PL 64.1173). To achieve this end, Boethius does not attempt a direct comparison of Aristotle and Cicero (indeed, even structuring this would have posed problems, since Aristotle works principally on the level of dialectic, while Cicero thinks in terms that are mainly rhetorical); instead, he draws the Greek topica from the work of Themistius, a Greek philosopher and orator of the 4th c. AD who composed rhetorical paraphrases of Aristotle’s Topics. Since this work has been lost, Boethius - together with Averroës (i.e. Ibn Rushd) - represents one of our chief sources for reconstructing Themistius’ work (Hasnawi 2007).
Boethius’ treatise comprises four books: the first, which functions as an introduction to the discipline, offers definitions of propositio, quaestio, conclusio, and argumentum; the second treats argumentatio and the types of loci, then lists Themistius’ maximae propositiones; the third explains Cicero’s division of the loci and shows how it is compatible with the division proposed by Themistius; and the fourth highlights the differences between loci rethorici and loci dialectici.
The work is attested by more than 220 codices: most of these come from the 13th c., while the six oldest date to the 10th c. (Milanese 1982; Nikitas 1990). The edition in Patrologia Latina 64.1173-1216 is based on the text edited by Heinrich Loriti “Glareanus” (Basel 1546 and 1570). In the second half of the 13th c., the De differentiis topicis was translated into Greek by Manuel Holobolos, a Byzantine orator in the service of Emperor Michael VIII Palaiologos, who probably made use of the text during his time teaching grammar and rhetoric. The work must have enjoyed some success, as Holobolos’ translation has come down to us in a full 21 manuscripts, dating primarily to the 15th and 16th c. (Fisher 2003). [M. Ferroni; tr. C. L. Caterine].