The Missing Logic: Traces of a Lost Book on Hypothetical Syllogistic in Avicenna's Risāla Mūǧaza fī Uṣūl al-Manṭiq

Do Avicenna’s extant works preserve any trace of his now-lost early philosophical production? This paper considers a hitherto neglected text, namely the chapter “On Hypothetical Propositions” from Avicenna’s “Concise Treatise on the Principles of Logic” (Risāla mūǧaza fī uṣūl al-manṭiq, henceforth: RM). The new evidence offered by the RM chapter in question will lead to a different reading of another well-known passage of Avicenna’s reworking of Aristotle’s Prior Analytics (Qiyās) from the “Book of Healing” (Kitāb al-šifāʾ). The clues gathered from an analysis of these two works will finally lead us to ponder the possibility that Avicenna may in fact have composed a (now lost) work on hypothetical propositions and syllogisms. Since Avicenna’s RM is to date unedited, an edition, as well as an English translation of the relevant chapter, is also provided in the Appendix of this paper.