Skip to main content

Hellenistic Thought


The Hellenistic era extends from the death of Alexander the Great in 323 BCE to the conquest of Egypt by the Romans in 30 BCE. Though defined in terms of political events, it is also host to distinctive developments in Greek intellectual life. Chief among these are the foundation and consolidation of organized schools as the focus of philosophical life, especially in Athens; the growing independence of various special sciences from their original philosophical context; and a geographical expansion (in the wake of Alexander's conquests and the foundation of Greek-speaking kingdoms in the eastern Mediterranean) that had significant long-term consequences. The intellectual life of Hellenistic Greece changed again as Roman political authority gradually came to dominate in the region. Throughout this period, Greek intellectuals (both philosophers and scientists) became more prominent and important in civic life, often achieving political recognition even in foreign cities; in 155 BCE three prominent philosophers, none of them from Athens, were chosen to represent the city on an embassy to Rome. Prominent intellectuals were offered patronage by the new Hellenistic kingdoms.

The first major organized school at Athens was the Academy, founded by Plato. Aristotle's associate and successor, Theophrastus, and later Strato of Lampsacus, carried on the traditions of his work in the Lyceum. Other philosophical schools in the fourth century were of minor importance, although the hedonistic school based at Cyrene in North Africa was influential. Yet within the first few decades of the Hellenistic era two major new schools, representing significant philosophical directions with lasting influence, were established. Epicurus, the founder of Epicureanism, was an Athenian and established the Garden there, but his followers spread around the Aegean basin in a network of smaller institutions that remained connected to the original school. Zeno came from the town of Citium on the island of Cyprus to establish his school in the Painted Stoa in the Athenian agora, and throughout its history it continued to attract philosophers from all over the Hellenistic Greek world, especially Asia Minor.

Epicureanism and Stoicism quickly became successful and attracted adherents for centuries to come. Epicureanism revived the atomistic physics pioneered by Leucippus and Democritus and linked it tightly with a hedonistic ethics and quietistic political philosophy. Stoicism depended on the mainstream Socratic tradition; its cosmology and physics drew primarily on Plato and Aristotle and its ethical and political theory were heavily influenced by Socratic ideas colored by the Cynic tradition stemming from Diogenes of Sinope and Crates of Thebes.

Stoicism and Epicureanism were in some ways polar opposites. The former championed god's providence while Epicurus denied it. Stoic physics asserts the continuity of all matter (which is itself permeated by a divine cause giving it form), while for Epicurus all things, even the gods, are composed of atoms and void. Like Plato and Aristotle, Stoics believed that society and its institutions rest on deeply rooted features of human nature, but Epicureans held that societies are formed by agreements among people about mutual preservation and advantage. Stoicism (inspired in part by the dialectical school and Megarian philosophers) led the way in the development of logic and dialectic, while Epicurus rejected logic along with many other specialized intellectual endeavors as useless. For Epicurus even physics mattered only in so far as it was essential to achieving tranquility.

Despite these contrasts, the two schools shared a great deal. Both rested their philosophy on broadly empiricist epistemologies, according to which normal sensory experience was the ultimate source and criterion for knowledge, and both rejected the idea of causally efficacious incorporeal entities and emphasized the material foundations of all reality. Neither school could accept the central role of form, either in the Platonic version in which forms were separate from material particulars, or in the immanentist version of Aristotle, for whom form and matter were the two components of all concrete objects; nor could they embrace the concepts of an incorporeal deity or an immortal and incorporeal soul animating the body.

As these new schools emerged, the Academy changed its intellectual course; under the leadership of Arcesilaus it adopted a skeptical practice, devoting its energies not to the development and refinement of positive theories but to the dialectical criticism of those philosophers who claimed certainty for their own views. Stoicism was its chief target, and it can be argued that the main inspiration for this skeptical turn was the desire to refute those who claimed that the physical world could yield certain knowledge. The Academy maintained its dialectical approach for nearly two centuries; its high point came under the intellectual leadership of Carneades in the second century BCE. His followers came to disagree about the nature of his commitment to skepticism and gradually reverted to dogmatism, the conviction that knowledge is achievable. The Lyceum (sometimes also called the Peripatos) did not long maintain its philosophical vigor after the death of Theophrastus and its leaders became better known for their achievements in the sciences than in philosophy. Only Critolaus, the contemporary of Carneades, achieved importance in philosophy proper. The renewal of Aristotelianism had to await the end of the Hellenistic era.

With each generation the Stoic school changed and developed, with most of its leaders making significant innovations. The third head, Chrysippus of Soli, systematized and reworked nearly every aspect of Stoic thought, developed the formal logic for which the Stoics remained famous until the end of antiquity, and exerted control of the school's trajectory for several generations after. In the late second century Panaetius of Rhodes and his student Posidonius of Apamea made a comparable mark, reintegrating Platonic and Aristotelian influences into the school's intellectual life. By contrast, in all but details the Epicurean school was marked by conservatism and doctrinal unity.

The interaction between philosophical schools and the special sciences is a topic of particular interest in this period. Except for the medical texts in the Hippocratic Corpus, there are few traces of specialized scientific writing before 300 BCE, although Aristotle makes frequent allusions to an optical and astronomical literature that was distinct from philosophy and had a mathematical character. Hellenistic optics, as represented by Euclid's Optics, was the physical science that engaged most actively with philosophy. Euclid uses a geometrical apparatus to model a selection of phenomena of visual perception that reflect not only Aristotle's analysis of the objects of sense perception but also contemporary Hellenistic epistemological concern with the reliability of the senses. The Euclidean model, invoking rectilinear "visual rays" that radiate from eye to object, could be reconciled with Stoic physics as well as with the more eclectic materialism of Theophrastus and his Peripatetic successors.

Astronomy, by contrast, seems to have disengaged from philosophy after Aristotle. Deeply impressed by the regularity of astronomical phenomena and by Eudoxus's ingenious hypotheses of rotating spheres that seemed to account for them, Aristotle posited a sharp discontinuity between the irregularly changeable globe of matter at the centre of the cosmos, in which we dwell, and the eternally unchanging outer shell, composed of a distinct kind of matter, that is the realm of the sun, moon, planets, and stars. The Stoics and Epicurus, by rejecting this discontinuity, made it harder to reconcile their physics with the mathematically abstract celestial models of the astronomers. Astronomical writers such as Aristarchus in the third century and Hipparchus in the second relied on geometry, arithmetic, and optical observation as criteria for their models, and sometimes put forward alternative models to explain the same phenomena. In the view of a physically oriented philosopher such as Posidonius, the astronomers' models did not constitute proper explanation, which only the philosophers could provide. Nonetheless such results of astronomical reasoning as estimates of the sizes and distances of the sun and moon and Eratosthenes's measurement of the earth's circumference became commonplaces of philosophical discourse.

Mesopotamian traditions of divination from celestial phenomena were known in the Greek world as early as the third century, and the Stoics in particular took a lively interest in them as they did in other forms of divination. It was only about the beginning of the first century BCE, however, that a distinctly Greek astrology endowed with sufficient complexity and rationale to claim scientific status took form. Astrology was founded on a physical cosmology that was loosely derived from Peripatetic and Stoic physics, though most of its literature concerned niceties of prognostication, not the analysis of cause and effect. The Stoic poet Aratus's versified description of the constellations achieved remarkable popularity in antiquity; but on the whole the Stoics tended to disregard technical astronomy, perhaps because they were uncomfortable with its mechanistic character. The Skeptical schools, on the other hand, found an easy target in astrology's pretensions to exact knowledge of the future derived from inexactly observed or calculated motions of the heavenly bodies.

The Hellenistic period was the heyday of Greek geometry. Euclid, Archimedes, Apollonius of Perge, and a host of lesser mathematicians published work of enduring value on difficult problems, typically involving the properties of curves and the areas and volumes bounded by geometrical figures. Much mathematical research was motivated by optics, mechanics, and astronomy, but Hellenistic mathematicians seem to have kept more aloof from the philosophers than their predecessors of Plato's and Aristotle's time.

Alone among the scientific disciplines, medicine was characterized in the Hellenistic period by a division into sects or schools, comparable to the contemporary emergence of the great philosophical schools. The Hellenistic medical sects took their start from the prolific early third century physicians Herophilus and Erasistratus, whose theoretical pronouncements on physiology and medical practice were founded on a level of anatomical research and experimentation (reportedly including human vivisections) that was unprecedented in Greek medicine. In their approaches to physical and biological explanation these men and their followers owed something to Aristotle and perhaps more to the later Peripatetics. The "Herophilean" and "Erasistratean" schools seem to have less direct engagement with Stoicism or Epicureanism, though in common with those philosophical sects they accepted that knowledge of hidden causes of phenomena was both possible and useful.

The medical sect of Empiricists, which rose in the third century, rejected hidden causes as both unknowable and unhelpful in medical practice, and advocated instead a strategy for progressing systematically from individual trial-and-error experience to generalized, teachable practical knowledge without recourse to anatomical or physiological theory. The debates between the Empiricists and the other sects, grouped under the heading of Rationalists or Dogmatists, centered on both epistemology and research ethics; Empiricist physicians found natural intellectual allies in the philosophical Skeptics, especially the Pyrrhonists. Few Hellenistic physicians, however, were themselves philosophers, and a broad, intellectually respectable effort to bring together the many threads of current medical and philosophical thought had to wait for Galen in the second century CE. Galen's contemporary Ptolemy had a comparable reintegrating role with respect to Hellenistic physical science and philosophy.

The relationship between philosophy and medicine was paralleled by that between philosophical analysis of language and the emerging disciplines of grammar and philology. While critical speculation about language began in the Presocratic period and developed dramatically in the fourth century BCE, in the Hellenistic era the study of language achieved greater independence from philosophy without fundamentally severing its ties. Pergamum and Alexandria became centers for the critical study of ancient texts, especially Homer, and for the analysis of linguistic phenomena. At the same time, Epicureanism promoted a naturalistic understanding of the origin and nature of language and the Stoics made enormous advances not just in the area of logic (Chrysippus developed propositional logic in contrast to Aristotelian term logic) but also in the analysis of the parts of speech and semantic theory. Philosophers and grammarians debated the roles of rule-driven morphological analogy and the variability of actual linguistic usage (anomaly ) in the determination of linguistic norms. Here too Hellenistic developments laid the foundations for intellectual life in later antiquity.

At the end of the Hellenistic era, the dominance of Athens in Greek philosophical life came to an end. After the conquest of Athens by the Romans under Sulla during the Mithridatic wars (8886 BCE), philosophy, like science, spread out around the Mediterranean world. Rome itself, as well as Alexandria and Rhodes, became an important locus of philosophical activity as the Hellenistic age, and with it the Roman Republic, came to an end. At the beginnings of the Roman Empire, philosophy changed its character and turned for inspiration to the close study of the classic texts of Plato and Aristotle written centuries before. The Hellenistic era in Greek thought came to an end appropriately with the rise of a productive form of scholasticism and the revival of the classical schools of thought which have remained central to our understanding of ancient philosophy ever since.

See also Ancient Skepticism; Arcesilaus; Aristotelianism; Carneades; Chrysippus; Cyrenaics; Epicurus; Greek Academy; Panaetius of Rhodes; Posidonis; Stoicism; Strato and Stratonism; Theophrastus; Zeno of Citium.


For philosophical developments in the period the starting point is The Cambridge History of Hellenistic Philosophy (ed. K. Algra et al, Cambridge, U.K.: Cambridge University Press, 1999). Major texts and philosophical commentary are found in A. A. Long and D. N. Sedley, The Hellenistic Philosophers (2 vol.; Cambridge, U.K.: Cambridge University Press, 1987). For the sciences, G. E. R. Lloyd's Greek Science after Aristotle (London: Chatto and Windus, 1973) remains fundamental. For optics and its philosophical setting see Gérard Simon, Le regard l'être et l'apparance dans l'optique de l'antiquité (Paris: Seuil, 1988). H. von Staden, Herophilus: the art of medicine in early Alexandria: edition, translation and essays (Cambridge, U.K.: Cambridge University Press, 1989) and S. Cuomo, Ancient Mathematics (London: Routledlge, 2001) illuminate the intellectual world of Hellenistic medicine and mathematics.

Brad Inwood (2005)

Alexander Jones (2005)

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"Hellenistic Thought." Encyclopedia of Philosophy. . 21 Sep. 2017 <>.

"Hellenistic Thought." Encyclopedia of Philosophy. . (September 21, 2017).

"Hellenistic Thought." Encyclopedia of Philosophy. . Retrieved September 21, 2017 from

Learn more about citation styles

Citation styles gives you the ability to cite reference entries and articles according to common styles from the Modern Language Association (MLA), The Chicago Manual of Style, and the American Psychological Association (APA).

Within the “Cite this article” tool, pick a style to see how all available information looks when formatted according to that style. Then, copy and paste the text into your bibliography or works cited list.

Because each style has its own formatting nuances that evolve over time and not all information is available for every reference entry or article, cannot guarantee each citation it generates. Therefore, it’s best to use citations as a starting point before checking the style against your school or publication’s requirements and the most-recent information available at these sites:

Modern Language Association

The Chicago Manual of Style

American Psychological Association

  • Most online reference entries and articles do not have page numbers. Therefore, that information is unavailable for most content. However, the date of retrieval is often important. Refer to each style’s convention regarding the best way to format page numbers and retrieval dates.
  • In addition to the MLA, Chicago, and APA styles, your school, university, publication, or institution may have its own requirements for citations. Therefore, be sure to refer to those guidelines when editing your bibliography or works cited list.