ABSTRACT
For the Stoics, physics is that part of philosophical discourse that deals with all questions concerning the physical world, from foundational ontology to the empirical sciences such as astronomy and meteorology. The fundamental assertion underpinning all of Stoic physics is the claim that only bodies exist, a claim that dates back to Zeno himself. Zeno follows the giants in the Sophist by insisting that being or existence should be identified with body, despite the concession by Platos moderate materialists. The Stoics propose two material principles as the foundation for their physics, two principles that are presented in the surviving fragments using a variety of terms. The Stoics outline three principal conditions of pneuma, each reflecting a different level of tension. For the Stoics, then, the cosmos is a living being, and their cosmology is also a cosmobiology.
