  Of many possible candidates for consideration, the discussions around three logical doctrines seem to me to be particularly instructive. The first has to do with the subject matter of logic, something which needs to be identified if there is any prospect of presenting logic as a science (something most parties to the debate at least claim to want). The doctrine associated with Avicenna as to the subject matter of logic came to have decisive impact in the Latin logical tradition, though it was not the only doctrine in play through the later Arabic texts. The second and related set of doctrines has to do with offering an account of how the various logical disciplines—demonstration, dialectic, rhetoric and poetics—fit together. Inherited expectations of what disciplines a logical treatise should cover came under pressure from new disciplines derived from grammar and law; ultimately, the disciplines of dialectic, rhetoric and poetics were no longer treated in the ways they had been in the Aristotelian tradition. Finally, modal syllogistic was perhaps the most keenly disputed topic in logic through the twelfth and thirteenth centuries, and I offer an overview of one line of discussion which took place. I look in particular at arguments coming from eastern Iran in the thirteenth century—a tradition I call Maragha logic  (see 1.5.2 above)—because this was a period of particularly intense logical activity culminating in textbooks overwhelmingly important in the subsequent teaching of the discipline.