Modern study of Posidonius has been transformed since the mid-1960s by the collection of ancient evidence compiled by Ludwig Edelstein and Ian G. Kidd (1972), and minutely analyzed by Kidd (1988, 1999), which contains only texts that name Posidonius explicitly. The picture presented is undoubtedly too narrow, and an accurate assessment of Posidonius's achievement and influence must await further study of other texts in which his influence may be reliably detected. But even the newly circumscribed picture has made it increasingly clear that Posidonius largely adhered to basic Stoic doctrines and principles and that his main innovations lie in his breathtakingly comprehensive effort to integrate both natural and human sciences into Stoic cosmology, epistemology, and ethics. His range was encyclopedic, and while the bulk of his massive output was in physics (embracing also metaphysics, theology, and the special sciences), there is little he neglected.

In metaphysics Posidonius sought...