In This Article Expand or collapse the "in this article" section Posidonius

  • Introduction
  • Fragment Collections
  • Methodological Issues
  • Comprehensive Accounts
  • Logic and Mathematics
  • Other Special Sciences

Classics Posidonius
Teun Tieleman
  • LAST MODIFIED: 26 May 2021
  • DOI: 10.1093/obo/9780195389661-0365


Posidonius of Apamea (135–c. 51 BCE), Stoic philosopher, scientist, and historian, was one of the foremost intellectuals of his day. Born in Apamea, a Greek city in northwestern Syria, he came to Athens as a young man to study with Panaetius of Rhodes, then head of the Stoa. After his studies Posidonius took up residence in Rhodes, where he taught philosophy, wrote a large number of treatises, and was visited by prominent Romans, notably Cicero and Pompey. Having acquired Rhodian citizenship, he held high public office and took part in at least one embassy to Rome (87–86 BCE). In the 90s he traveled extensively in the Mediterranean world, studying the geography of its various regions and the habits and customs of its peoples. Of his many treatises none has survived. Until well into the last century the fragmentary and indirect state of the evidence led to divergent reconstructions of his thought, giving rise to the “Posidonian question” (see further commentary section under Fragment Collections). Today, there is a growing consensus that Posidonius by and large stayed within the philosophical framework he had inherited from his predecessors in the Stoic school: Zeno, Cleanthes, Chrysippus, and Panaetius. Even so, Panaetius and Posidonius are often referred to as the two main representatives of a phase in the history of Stoicism called Middle Stoicism, a term coined by the 19th-century German scholar Schmekel (Schmekel 1892, cited under Comprehensive Accounts). The underlying assumption is that they made significant adaptations to Stoicism, in particular by introducing Platonic and Aristotelian notions, e.g., in moral psychology. The extent to which they did has often been exaggerated and the motivation behind their references to Plato misunderstood. At the same time there is much that remains uncertain and controversial. What does seem certain is that Posidonius, in psychological analysis as elsewhere, insisted on the exploration of causes, going beyond the point where predecessors like Chrysippus believed this was needed or possible. Another feature that sets him apart from his fellow Stoics is that he undertook the study of history, geography, ethnography, geology, meteorology, astronomy, medicine and, not least, mathematics. He saw these “special sciences” as instrumental and subordinate but also indispensable to philosophy. His wide-ranging interests provided him with many opportunities to elaborate upon Stoic concepts and doctrines. He was one of the most important Stoics of antiquity.

Fragment Collections

None of Posidonius’s treatises have been preserved. We have to reconstruct his philosophy and scientific work from reports and quotations (“fragments”) from a great variety of sources such as Cicero, Strabo, Seneca, Plutarch, Galen, Cleomedes, and others. Some of these sources had access to Posidonius’s original expositions, while others drew upon intermediate sources. All of them pursue agendas of their own but never historiography in the modern sense. To complicate matters, Posidonius has been seen as the main inspiration behind passages or even entire books even in cases where their authors do not refer to him. The use of unnamed evidence was propelled by the assumption that Posidonius was a dominant influence on these later authors. It led to widely divergent reconstructions of his philosophy, especially in German studies of the second half of the 19th and first half of the 20th century, all starting from the materials collected in Bake 1810. Posidonius could be portrayed as an empirically minded scientist or a religiously inspired mystic or a curious blend of the two. Posidonius commanded a great deal of fascination as the “missing link” between classical and early Hellenistic philosophy on the one hand and later ancient philosophy (e.g., Neoplatonism) on the other. In hindsight, his name effectively labelled the then prevalent ignorance of many facets of Hellenistic philosophy. An obsession with determining individual sources also contributed to this tendency in the scholarship. This tendency to detect Posidonius behind the philosophical (and theological) literature of the imperial period has been aptly dubbed “Panposidonianism.” The Posidonian studies of Karl Reinhardt of the 1920s were more restrictive but raised questions of their own (see Comprehensive Accounts). The “Posidonian question” was therefore marked by quarrels on the source(s) of particular passages or books and the general question of Posidonius’s influence. In the 1930s Ludwig Edelstein laid the foundations for a collection that limited itself to named evidence as a way out of these problems. His work was continued and completed by Ian Kidd. Edelstein and Kidd 1972 (EK) has established itself as the standard fragment collection, to be used with Kidd 1988 and Kidd 1999, the accompanying commentary and translation. Theiler 1982 stands in the German tradition and so also includes unnamed evidence. Vimercati 2004 attempts to strike a somewhat precarious balance between Edelstein and Kidd 1972 and Theiler 1982. The older collection of Jacoby 1926 limits itself to the historiographical fragments.

  • Bake, J. 1810. Posidonii Rhodii reliquiae doctrinae collegit atque illustravit Janus Bake. Accedit Wyttenbachii annotatio. Lugduni Batavorum: apud Haak et socios.

    A product of a bygone era of scholarship, this fragment-collection was an admirable achievement and the basis of much work on Posidonius in the 19th century and beyond, for better or worse.

  • Edelstein, L., and I. G. Kidd. 1972. Posidonius. Vol. 1, The fragments. Cambridge, UK: Cambridge Univ. Press.

    A landmark in Posidonian studies, this fragment collection by Edelstein and Kidd is based on the principle that the historical reconstruction of Posidonius’s philosophy should be based upon, or at least start from, texts that refer explicitly to Posidonius. This principle still permits the inclusion of large chunks of indirect material (reports, paraphrase) as in the case of Galen, PHP IV and V, who refers quite a lot to Posidonius (F150–187).

  • Jacoby, F. 1926. Fragmente der griechischen Historiker II. Zeitgeschichte, A. Universalgeschichte und Hellenika. Nr.87 (= pp. 222–317). C Kommentar zu Nrs. 64–105 (Nr. 87 = pp.154–220). Berlin: Weidmann.

    Collection of fragments from Posidonius’s Histories and On the Ocean, together with some unnamed texts, e.g., from Diodorus Siculus (F 108, though cautiously offered as an “Anhang”). Fragments with book-titles are presented separately from those without (as in Edelstein and Kidd 1972). Reprint Leiden, The Netherlands: Brill, 1996, 1993; online edition, Leiden, The Netherlands: Brill, 2007–).

  • Kidd, I. G. 1988. Posidonius. Vol. 2, The Commentary: (i) Testimonia and Fragments 1–149; (ii) Fragments 150–293. Cambridge, UK: Cambridge Univ. Press.

    Meticulous commentary on the fragments in the Edelstein-Kidd collection. An indispensable tool. Very good on the scientific fragments in particular.

  • Kidd, I. G. 1999. Posidonius. Vol. 3, The translation of the fragments. Cambridge, UK: Cambridge Univ. Press.

    This volume offers the translation of the fragments presented in Edelstein and Kidd 1972. In addition, there is a good introduction and useful notes on the texts themselves.

  • Theiler, W. 1982. Poseidonios. Die Fragmente. I Texte. II Erläuterungen. Berlin: De Gruyter.

    DOI: 10.1515/9783111610160

    This rival collection stands in the German tradition of Posidonian studies and so offers an “extended Posidonius” partly based on texts that do not refer to Posidonius by name (e.g., from Diodorus Siculus and Plotinus). It also diverges from Edelstein and Kidd 1972 in how the material has been arranged. To be used with caution.

  • Vimercati, E. 2004. Posidonio. Testimonianze e Frammenti. Testo greco e latino a fronte. Introduzione, traduzione, commentario e apparati di E.V.; presentazione di Roberto Radice. Bompiani, collana Il pensiero occidentale. Milan: Bompiani.

    Fragment collection with translation and commentary that attempts to steer a middle course between the more restrictive policy of Edelstein and Kidd 1972 and the more inclusive one of Theiler 1982. This aspect and the commentary are open to criticism: see Algra 2014 under Methodological Issues.

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