In An. Post. I, 2, 72 a 8ff., Aristotle gives a description of the kinds of premisses that can occur in a demonstration. It is the purpose of this paper to explore some difficulties that arise in the interpretation of this passage and of the related passage at An. Post. I, 10, 76b 33 ff.

The Posterior Analytics has long been considered to raise and to go part of the way toward answering important philosophical questions concerning existence and essence. In the recent literature, however, scholars have been taking the view that the existence-essence distinction is not captured.