Diogenes, "the Cynic," Greek philosopher, was born at Sinope about 412 BC, and died in 323 at Corinth, according to Diogenes Laėrtius, on the day on which Alexander the Great died at Babylon.
His father, Icesias, a money-changer, was imprisoned or exiled on the charge of adulterating the coinage. Diogenes was included in the charge, and went to Athens with one attendant, whom he dismissed, saying, "If Manes can live without Diogenes, why not Diogenes without Manes?" Attracted by the ascetic teaching of Antisthenes, he became his pupil, despite the brutality with which he was received, and rapidly excelled his master both in reputation and in the austerity of his life. The stories which are told of him are probably true; in any case, they serve to illustrate the logical consistency of his character. He inured himself to the vicissitudes of weather by living in a tub belonging to the temple of Cybele. The single wooden bowl he possessed he destroyed on seeing a peasant boy drink from the hollow of his hands.
On a voyage to Aegina he was captured by pirates and sold as a slave in Crete to a Corinthian named Xeniades. Being asked his trade, he replied that he knew no trade but that of governing men, and that he wished to be sold to a man who needed a master. As tutor to the two sons of Xeniades, he lived in Corinth for the rest of his life, which he devoted entirely to preaching the doctrines of virtuous self-control. At the Isthmian Games he lectured to large audiences who turned to him from Antisthenes. It was, probably, at one of these festivals that he met Alexander the Great. The story goes that Alexander, thrilled at coming face to face with the famous philosopher (in his tub), asked if there was any favour he might do for him. Diogenes asked him not to stand between him and the sun, to which Alexander replied "If I were not Alexander, I would be Diogenes."
On his death, of which there are several accounts, the Corinthians erected to his memory a pillar on which there rested a dog of Parian marble. Virtue, for him, consisted in the avoidance of all physical pleasure; that pain and hunger were positively helpful in the pursuit of goodness; that all the artificial growths of society appeared to him incompatible with truth and goodness; that moralization implies a return to nature and simplicity. In his words, "Man has complicated every simple gift of the Gods." He has been credited with going to extremes of impropriety in pursuance of these ideas; probably, however, his reputation has suffered from the undoubted immorality of some of his successors. Both in ancient and in modern times, his personality has appealed strongly to sculptors and to painters. Ancient busts exist in the museums of the Vatican, the Louvre and the Capitol. The interview between Diogenes and Alexander is represented in an ancient marble bas-relief found in the Villa Albani. Rubens, Jordaens, Steen, Van der Werff, Jeaurat, Salvator Rosa and Karel Dujardin have painted various episodes in his life.
Diogenes is the first person known to have thought, and said, "I am a citizen of the whole world," rather than of any particular city or state.
The chief ancient authority for his life is Diogenes Laertius vi. 20; see also Mayor's notes on Juvenal, Satires, xiv. 308-3 14.