Posidonius' Cosmology

Posidonius incorporated important concepts of Peripatetic physics into his system. Posidonius adopted a finitist cosmological model where the extra- cosmic void was not infinite but just as large as the cosmos’ size at the time of the conflagration (F 84/97a E ̶ K). He accepted the idea that there are ab- solute directions towards which the elements naturally tend to move and in which they will naturally remain (F 93 E ̶ K). Similarly, Posidonius concei- ved the four elements as interactive given the new relationship of mutual contrariety, and adopted a physicalist approach where the hot elements are active (F 93, F 101 E ̶ K). The analysis of the long fragments preserved in Strabo (F 229 E ̶ K) and Priscianus Lydus (F 219 E ̶ K) has further shown the significance of heat as an active power in Posidonius’ physics.