Abstract

This specimen of a forthcoming book on the void in ancient natural philosophy by using an example illustrates the problems that confront the scholar. The term εὐτονία, used by Chrysippus, occurs in the Pneumatics of Hero of Alexandria in connection with empty pores. Has he borrowed the notion from Stoic philosophy, or was Strato of Lampsacus, older than Chrysippus, the first to use it? In all probability it was Ctesibius who independently of Stoic philosophy applied the term to account for the kinetic qualities of the material used for his inventions, and Philo Byzantius took over the notion from him. Hero may have derived it from Ctesibius either directly or via Philo.