Diogenes Laërtius

Diogenes Laërtius (lived ad 3rd century?), Greek author whose fame rests on his ten-volume history of Greek philosophy, the only one of its kind. Diogenes’s history has been preserved in its entirety, except for one missing piece, and is an important source of our knowledge of Greek philosophy. One of the traditional titles for these volumes is Lives and Opinions of the Most Famous Philosophers and a Brief Summary of the Main Doctrines of All Schools.

The first of Diogenes’s ten books asserts the strictly Greek origin and character of philosophy and presents the prehistory of the philosophy. Books two through seven deal with the Ionic philosophers, such as Anaximander, Anaximenes, and Anaxagoras, and they discuss the Athenian philosopher Socrates, who had an immeasurable effect on Western philosophy. They also contain information about historians and philosophers connected to Socrates, including Greek historian Xenophon who wrote about Socrates; Aristippus, student of Socrates and founder of the Cyrenaic school of hedonism; and Euclid of Megara, another student of Socrates. One of these books is devoted to the Greek philosopher Plato in its entirety. The famous Greek philosopher Aristotle and his Peripatetic school are discussed in these books, and, Greek philosopher Antisthenes, earliest of the Cynics is discussed. Book eight is devoted in large part to Greek philosopher and mathematician Pythagoras, Greek philosopher and poet Empedocles, and Greek astronomer and mathematician Eudoxus. Book nine starts with Heraclitus, a founder of Greek metaphysics, and Xenophanes, a Greek philosopher, poet, and religious reformer. Book nine continues with Greek philosophers Parmenides, Zeno of Elea, Democritus, and Protagoras, and also includes Pyrrho, founder of skepticism, and his disciples. Book ten is devoted to Greek philosopher Epicurus and his school. Diogenes’s history is mainly a compilation of information taken from biographies, histories of philosophy, and bibliographies. The content of the books ranges from competent summaries of doctrines to inauthentic gossip. It also contains some documents of prime importance, such as the text of three letters by Epicurus.