 In opposition to the atomists, the Stoic philosophers Zeno of Cition (fl. 250 BCE) and Chrysippus (280–206 BCE) upheld the Aristotelian position that space, time, matter and motion are all continuous (Sambursky 1954 [1956], 1959; White 1992). And, like Aristotle, they explicitly rejected any possible existence of void within the cosmos. The cosmos is pervaded by a continuous invisible substance which they called pneuma (Greek: “breath”). This pneuma—which was regarded as a kind of synthesis of air and fire, two of the four basic elements, the others being earth and water—was conceived as being an elastic medium through which impulses are transmitted by wave motion. All physical occurrences were viewed as being linked through tensile forces in the pneuma, and matter itself was held to derive its qualities from the “binding” properties of the pneuma it contains.