Peter Adamson (LMU) gives a talk at the MCMP Colloquium (22 November, 2012) titled "Logic as an Instrument in Greek and Arabic Philosophy". Abstract: As is well known, the Aristotelian works on logic were collectively referred to in antiquity as the Organon, meaning "instrument". Ancient Aristotelians took this seriously: for them, logic is not a part of philosophy but only a tool or instrument which one should ideally learn before embarking on the study of philosopher proper. This view was not universally adopted in antiquity, however. The Stoics made logic one of three broad areas of philosophy (along with ethics and physics), and thought of these areas as closely interrelated "parts". In this paper I explore the philosophical consequences of this apparently rather superficial disagreement; for instance, it bears on the question of the extent to which logic was perceived in the ancient world as a "formal" discipline. I also pursue the part vs. instrument debate into the Arabic tradition. There, we find adherents of Aristotle torn between their desire to agree that logic is a mere instrument, and not a part, of philosophy, and their desire to show the importance of logic against its detractors.