The Art and Science of Logic: A Translation of the Summulae dialectices with notes and introduction by Roger Bacon, and: On Signs (Opus maius, Part 3, Chapter 2) by Roger Bacon (review)

These books translate two important works (or rather, one complete work and a hitherto untranslated part of another) by the influential thirteenth-century Franciscan thinker, Roger Bacon (c. 1214–94). A brilliant polymath who sought to reform the university curriculum, Bacon championed science and helped bring Aristotle’s logic and natural philosophy to greater prominence in Arts education at both Paris and Oxford. He used his grasp of the “new” logic, founded on Aristotle’s Prior and Posterior Analytics, Topics, and Sophistical Refutations (“new” because these works reappeared in the West in the twelfth century, after having been lost since late antiquity), to revitalize the study of dialectic and, ultimately, all other arts and sciences that employed logical proof and dialectical argumentation.

The Art and Science of Logic (translating the critical edition of the Summulae dialectices by Alain de Libera) is a comprehensive treatment of Aristotelian logic patterned after the organon. Beginning with terms, Bacon moves on to the various types of propositions (or “statements,” as rendered here), ending with a section on argumentation in which the properties of the syllogism as well as topics and fallacies are discussed. The treatment is remarkably thorough, and reads like a textbook written for students to review and consult on especially difficult points, such as on the differences between pure, infinite, and privative negation (one needs to clarify whether someone negating the term ‘just’ means ‘not just,’ or ‘non-just,’ or ‘unjust,’ 77–78). The work was probably completed at Paris around 1247, which makes it early both in Bacon’s career and among works of terminist logic more generally. The translator, Thomas S. Maloney, places Bacon’s Logic alongside three other well-known treatises on logic and semantics from the mid-thirteenth century: the Introduction to Logic of William of Sherwood (c. 1190–1249), the Tractatus or Summulae logicales of Peter of Spain (precise dates uncertain), and the Logic of (ps.-) Lambert of Auxerre, which we now know to have been written by a Dominican named Lambert of Lagny (fl. 1250s). Together, these works changed the face of medieval logic, moving it from the Boethian paradigm of propositional logic, which reached its zenith in Peter Abelard (1079–1142), to the logic of terms and consequences we find in the work of the great fourteenth-century logicians such as William of Ockham (c. 1285–1347) and John Buridan (1300–1361).

The second book, On Signs, translates the missing second chapter from the third part of Bacon’s most famous work, the Opus Maius, composed c. 1267, after his return to Oxford. The Latin text was rediscovered in 1978 by Jan Pinborg, Lauge Nielsen, and Karin Margareta Fredborg. Here, Bacon refines the naturalistic and externalist semantic theory he had begun sketching in The Art and Science of Logic, presenting many of his most innovative (and controversial) doctrines, for example, his non-Augustinian emphasis on the relation between a sign and its interpreter rather than on the relation between a sign and what it signifies (35–45); his theory of the original imposition of a word, and the associated account of the five modes of equivocation (45–46, 56–62); his new understanding of ampliation and restriction in terms of “equivocal reimpositions” (80–86). What is striking throughout is the extent to which Bacon reworks the tradition of logic and semantics he inherited from his predecessors at Oxford and Paris. As his translator nicely puts it, “Bacon was on a quest that involved looking at everything in new ways” (On Signs...