Abstract

In the Treatise On the Heavens II, 1 [ 40 ], Plotinus rejects the explanation of Aristotle who, in De caelo I, 2-3, considers the “fifth body”, ether, the incorruptible matter of celestial bodies and heavens and, hence, different from the sub-lunar world’s four elementary bodies. Plotinus’ argument at tempts to found the kind of perpetuity which numerical identity implies -the identity which is proper of heavens and celestial bodies- on the harmony that reigns between their body and soul. This way, the Plotinian exeges is of the Aristotelian Treatise integrates the themes already raised in the Platonic Phaedrus and Timaeus. In this article I attempt to expound: 1 ) the concepts of perfection and the cosmological dualism in Aristotle, 2) the problem of the cosmos’ perpetuity, 3) the Plotinian search of a more satisfactory explanation, and 4) the theme of the two regions: sub-lunar and supra-lunar.