What logical works did Peter Abelard write about Porphyry and Aristotle?
Peter Abelard was a pivotal 12th-century logician who produced three sets of commentaries and glosses on Porphyry’s Isagoge and Aristotle’s Categories and De interpretatione. These works include:
- Introductiones parvulorum (which also contains glosses on works by Boethius)
- Logica “Ingredientibus”
- Logica “Nostrorum petitioni sociorum” (focused solely on the Isagoge)
In addition to these commentaries, Abelard authored an independent treatise on logic titled Dialectica. Through these writings, he explored sophisticated logical topics such as the role of the copula in categorical propositions, modal notions like possibility, future contingents, and conditional propositions known as consequences. His work significantly advanced medieval logic by building upon the limited sources available to him, which consisted primarily of the aforementioned texts by Aristotle and Porphyry, alongside the commentaries of Boethius.1