It is a commonplace that ancient commentators would have worked to systematise Aristotle. In doing so, they would have ignored all that was exploratory and problematic in the Aristotelian thought. Alexander of Aphrodite would offer an typical example of this tendency when he seeks to make metaphysics a demonstrative science. In this chapter I examine his use of the dialectical method in metaphysics, in particular in his exegesis on Metaphysics Beta, and in his practice of the aporetic method. Against the idea that Beta’s aporias are no longer genuine puzzles, I would like to show, on the one hand, that aporia retains, in Alexander, an authentically exploratory function and, on the other hand, that its use in metaphysics is not so much a matter of systematization as of the accomplishment of the organon status granted to dialectics. Thanks to the dialectical method, Alexander maintains this exploratory character of aporias within a scientific approach. If we show the heuristic role of the dialectic as an integral part of science, we will then be able to better base the idea that Alexander maintains the exploratory character of the aporias.