Perfection and Reduction in Aristotle’s Prior Analytics

This chapter argues that perfecting a syllogistic mood is not the same as reducing it to another mood. To perfect a mood is to make its validity evident, which may or may not be done by reducing it to a perfect one; reduction works between moods of all figures, perfect or not. The epistemic priority of the first-figure moods led some later Peripatetics to claim that the imperfect moods owed their validity to the perfect ones and would not be valid without them. Boethus of Sidon (first century BC) refuted them by arguing that all the valid moods are perfect, at least in some cases appealing to the terminology of parts and wholes that Aristotle himself uses at the beginning of chapter 4 of Prior Analytics I when introducing the moods of the first figure.