The aim of this paper is to explore how the cosmic soul works and how it accomplishes its providential and demiurgic tasks in Chrysippus’ system. Drawing on (i) the analogy Chrysippus establishes between the individuum and the cosmos and (ii) biological and medical theories of respiration, digestion, and pulse, I will show that the movements of Chrysippus’ cosmic soul reproduce the processes of digestion, pulse, and respiration at a cosmic level. My claim is that Chrysippus, in addition to adopting Praxagoras’ (...) notion that inhaled air nourishes pneuma—well established in the scholarship—appropriated Aristotle’s complex mechanism of respiration and digestion based on the teleological role of cold air, crucial for preserving vital heat. So understood, Chrysippus’ application of biological notions to cosmology allows him to endow the active principle with effective causation throughout the cosmos. (shrink)

The present study partly supports, partly corrects, and partly complements recent discussions of Arius Didymus fr. 23 and fr. 25 Diels, Aetius I, 20, 1 and Sextus Empiricus AM X, 3-4 = PH III, 124. It proposes a comprehensive interpretation of the first text (A.I), defends the attribution of its content to Zeno of Citium (A.II), interprets the Stoic definitions of space, place and void to be found in the other sources (B.I) and again vindicates the attribution of the core (...) definitions to Zeno (B.II). The central methodological principle is the presumption of innocence for sources.The main conclusions of (A) are: 1. Arius Didymus' fr. 23 deals only with the coherence and the structure of the cosmos, not with its immobility; 2. The coherence of the cosmos, as that of any object, is determined by its hexis which pushes its parts towards its centre; 3. The structure of the cosmos, its stratification into the four concentric spheres of the elements, is determined by the combined effect of (a) the thrust downwards they all undergo from the cosmos' hexis; (b) their own natural weight or lightness and (c) the relative quantitative values of these weights or lightnesses; 4. The reasons adduced against Zeno's authorship are not based on the evidence but on the now prevalent disparaging sceptical approach towards Stobaeus' way of excerpting from Arius.The main conclusions of (B) are: 1. There is no deep contradiction between the various de finitions of space ascribed by our sources to Zeno, Chrysippus and the Stoics in general: what Chrysippus denied was the form of the de finition attributed to Zeno by Aetius, not the concept de fined, even though this form seems to have prevailed later in the school; 2. There is no good reason therefore to question its ascription to Zeno as some modern researchers have done; 3. Here again the error is due to a predominantly sceptical approach towards the reliability of our sources. (shrink)

Void is at the heart of Stoic metaphysics. As the incorporeal par excellence, being defined purely in terms of lacking body, it brings into sharp focus the Stoic commitment to non-existent Somethings. This article argues that Stoic void, far from rendering the Stoic system incoherent or merely ad hoc, in fact reflects a principled and coherent physicalism that sets the Stoics apart from their materialist predecessors and atomist neighbors.

While it is well known that Plutarch’s De facie in orbe lunae was a major source of inspiration for Galileo’s Sidereus nuncius, its influence on his Dialogo sopra i due massimi sistemi del mondo, and especially on his views on gravity, has not been sufficiently explored. This essay offers the first systematic comparison of Plutarch’s and Galileo’s accounts of gravity by focusing on four themes: the thought experiment of a stone falling in a tunnel passing through the center of the (...) Earth; the account of gravity as a tendency to unite with the whole; the view that the Moon is a separate center of attraction; and the impossibility of attraction by an incorporeal point. The essay analyzes the role that these themes play in De facie and in the Dialogo, trying to understand how Galileo appropriated, reworked, and expanded on Plutarch’s views. (shrink)

In contrast to other ancient philosophers, Epicurus and his followers famously maintained the infinity of matter, and consequently of worlds. This was inferred from the infinity of space, because they believed that a limited amount of matter would inevitably be scattered through infinite space, and hence be unable to meet and form stable compounds. By contrast, the Stoics claimed that there was only a finite amount of matter in infinite space, which stayed together because of a general centripetal tendency. The (...) Roman Epicurean poet Lucretius tried to defend the Epicurean conception of infinity against this Stoic alternative view, but not very convincingly. One might suspect, therefore, that the Epicureans’ adherence to the infinity of matter was not so much dictated by physical arguments as it was motivated by other, mostly theological and ethical, concerns. More specifically, the infinity of atoms and worlds was used as a premise in several arguments against divine intervention in the universe. The infinity of worlds was claimed to rule out divine intervention directly, while the infinity of atoms lent plausibility to the chance formation of worlds. Moreover, the infinity of atoms and worlds was used to ensure the truth of multiple explanations, which was presented by Epicurus as the only way to ward off divine intervention in the realm of celestial phenomena. However, it will be argued that in all of these arguments the infinity of matter is either unnecessary or insufficient for reaching the desired conclusion. (shrink)