Diogenes Laertius

Lives and Opinions of Eminent Philosophers

This work is a comprehensive biographical and doxographical compendium in ten books, recording the lives, anecdotes, writings, and doctrines of ancient Greek philosophers. Tracing the origin of philosophy to the Greeks, the author organizes the entire tradition into two primary successions—the Ionian and the Italian schools—structured around master-disciple lineages. The narrative begins with the Seven Sages and Thales, then moves through Socrates and the various Socratic branches, including Plato's Academy, Aristotle's Lyceum, the Cynics, and the Stoics with their tripartite system of logic, physics, and ethics. It then turns to the Italian branch, examining Pythagoras, the Eleatics, the atomism of Democritus, and Pyrrhonian skepticism, which advocates the suspension of judgment. Finally, the entire tenth book is devoted to Epicurus, concluding the work with his atomistic physics, the pursuit of untroubled peace of mind (ataraxia), and extensive transcriptions of his own letters and Principal Doctrines.