Diogenes Laërtius

Diogenes Laërtius (/daɪˈɒdʒᵻniːz leɪˈɜːrʃiəs/; Greek: Διογένης Λαέρτιος, Diogenēs Laertios; fl. c. 3rd century AD) was a biographer of the Greek philosophers. Nothing is definitively known about his life, but his surviving Lives and Opinions of Eminent Philosophers is a principal source for the history of Greek philosophy.

Although not definitive, Laërtius must have lived after Sextus Empiricus (c. 200), whom he mentions, and before Stephanus of Byzantium and Sopater of Apamea (c. 500), who quote him. His work makes no mention of Neoplatonism, even though it is addressed to a woman who was "an enthusiastic Platonist". Hence he is assumed to have flourished in the first half of the 3rd century, during the reign of Alexander Severus (222–235) and his successors.

The precise form of his name is uncertain. The ancient manuscripts invariably refer to a "Laertius Diogenes", and this form of the name is repeated by Sopater and the Suda. The modern form "Diogenes Laertius" is much rarer, used by Stephanus of Byzantium, and in a lemma to the Greek Anthology. He is also referred to as "Laertes" or simply "Diogenes".

The origin of the name "Laertius" is also uncertain. Stephanus of Byzantium refers to him as "Διογένης ὁ Λαερτιεύς" (Diogenes ho Laertieus), implying that he was the native of some town, perhaps the Laerte in Caria (or another Laerte in Cilicia). Another suggestion is that one of his ancestors had for a patron a member of the Roman family of the Laërtii. The prevailing modern theory is that "Laertius" is a nickname (derived from the Homeric epithet Diogenes Laertiade, used in addressing Odysseus) used to distinguish him from the many other people called Diogenes in the ancient world.

His home town is unknown (at best uncertain, even according to a hypothesis that Laertius refers to his origin). A disputed passage in his writings has been used to suggest that it was Nicaea in Bithynia.

The work by which he is known, Lives and Opinions of Eminent Philosophers, was written in Greek and professes to give an account of the lives and sayings of the Greek philosophers. Although it is at best an uncritical and unphilosophical compilation, its value, as giving us an insight into the private lives of the Greek sages, led Montaigne to exclaim that he wished that instead of one Laërtius there had been a dozen. On the other hand, modern scholars advise that we treat Diogenes' testimonia with care, especially when he fails to cite his sources: "Diogenes has acquired an importance out of all proportion to his merits because the loss of many primary sources and of the earlier secondary compilations has accidentally left him the chief continuous source for the history of Greek philosophy." Werner Jaeger damned him as "that great ignoramus".

He is criticized primarily for being overly concerned with superficial details of the philosophers' lives and lacking the intellectual capacity to explore their actual philosophical works with any penetration. However, according to statements of the 14th-century monk Walter Burley in his De vita et moribus philosophorum, the text of Diogenes seems to have been much fuller than that which we now possess.

Diogenes divides his subjects into two "schools" which he describes as the Ionian/Ionic and the Italian/Italic; the division is somewhat dubious and appears to be drawn from the lost doxography of Sotion. The biographies of the "Ionian school" begin with Anaximander and end with Clitomachus, Theophrastus and Chrysippus; the "Italian" begins with Pythagoras and ends with Epicurus. The Socratic school, with its various branches, is classed with the Ionic, while the Eleatics and sceptics are treated under the Italic.

It has been suggested that Diogenes was an Epicurean or a Skeptic. He passionately defends Epicurus in Book 10, which is of high quality and contains three long letters (attributed to Epicurus) explaining Epicurean doctrines. He is impartial to all schools (in the manner of the ancient skeptics), and he carries the succession of Pyrrhonism further than the other schools. At one point, he even seems to refer to the Skeptics as "our school." On the other hand, most of these points can be explained by the way he uncritically copies from his sources. It is by no means certain that he adhered to any school, and he is usually more attentive to biographical details.

In addition to the Lives, Diogenes was the author of a work in verse on famous men, in various metres, which he called Epigrammata or Pammetros (Πάμμετρος).

• Diogenis Laertii Vitae philosophorum edidit Miroslav Marcovich, Stuttgart-Lipsia, Teubner, 1999–2002. Bibliotheca scriptorum Graecorum et Romanorum Teubneriana, vol. 1: Books I–X ISBN 9783598713163; vol. 2: Excerpta Byzantina; v. 3: Indices by Hans Gärtner.
• Lives of Eminent Philosophers, edited by Tiziano Dorandi, Cambridge: Cambridge University Press, 2013 (Cambridge Classical Texts and Commentaries, vol. 50, new radically improved critical edition).
• Translation by R.D. Hicks:
  •  "Index". Lives of the Eminent Philosophers (Two volume ed.). Loeb Classical Library. 1925. 
  • Lives of Eminent Philosophers. I. Harvard University Press, Loeb Classical Library. 1925. ISBN 978-0-674-99203-0. 
  • Lives of Eminent Philosophers. II. Harvard University Press, Loeb Classical Library. 1925. ISBN 978-0-674-99204-7.