Historians of the scientific thought of ancient Greece have paid considerable attention to the atomic School and have analysed the origins, basic notions and trends of the theories of Leucippos, Democritos and Epicuros and also investigated their influence on later generations. Among the reasons for the prominence which has been given to the Greek atomic theory, the three most important are the following: the striking similarity between some of the Greek concepts, based entirely on intuition, and those of the modern theory which have been confirmed by experience; the conclusions which the Greeks drew from their assumptions by applying methods...

According to the Stoic conception, the cosmic scene of, material events, including conglomerate matter as well as space between bodies, is made up of a continuous whole. Like Aristotle, the Stoics exclude emphatically any possible existence of a void within the cosmos.¹ However, their cosmos is, in contradiction to that of Aristotle, an island embedded in an infinite void.² The cosmos is filled with an all-pervading substratum calledpneuma, a term often used synonymously withair.³ A basic function of the pneuma is the generation of the cohesion of matter and generally of the contact between all parts of the...

The specific Stoic attitude which attributes corporeality to everything capable of acting and being acted upon, including even the soul, had a decisive influence on the development of the dynamic aspect of their notion of continuity. The conception of the soul as a motive force can be traced back right to the beginning of Greek science, as pointed out by Aristotle in a well-known passage ofDe anima¹: Thales seems to have attributed a soul to the magnet in order to explain its action on iron; Alcmaeon held that the soul is immortal because of its ceaseless movement, “for all...

From the concept of the continuum and the dynamics of its parts which the Stoics developed, they managed to advance and to make significant progress in the epistemology of the causal nexus. The history of modern physics has taught us that the analysis of the problem of causality has been decisively assisted and furthered by two basic methods which were foreign to Greek antiquity—systematic experimentation and the mathematization of science. The refinement of experimental techniques on the one hand revealed the complexity of apparently simple phenomena and on the other hand made it possible to decompose them into a...

The most important outcome resulting from the Stoic dynamic notion of the continuum was their doctrine of causality. However, this notion affected their physical thought in a much wider sense than that determined by an asymmetrical and time-dependent relationship such as is exhibited by the causal nexus. The Stoics, for the first time in Greek science, introduced the symmetrical concept of interaction between members of certain classes or structures. We have already seen (ch. I, §2) that hexis represents the highest type of all possible structures, i.e. an entity which exhibits “communication” (diadosis) between the individual members and the whole....