 Although his teacher Panaetius had doubted divination, Posidonius used Platonic philosophy to support his belief in divination — whether through astrology or prophetic dreams — as a kind of scientific prediction.Some fragments of his writings on astronomy survive through the treatise by Cleomedes, "On the Circular Motions of the Celestial Bodies", the first chapter of the second book appearing to have been mostly copied from Posidonius.Posidonius advanced the theory that the Sun emanated a vital force which permeated the world.