Diogenes of Sinope, who lived in the fourth century BCE, was the prototype of the Cynics, who probably were so called from Diogenes' Greek nickname, the Dog (kuon; adjective form, kunikos). Tradition held that on coming to Athens in exile, he was influenced by Antisthenes' teaching; Diogenes' ascetic distortion of Socratic temperance gives some point to Plato's supposed remark that he was a "Socrates gone mad."

It is not easy to recover the philosopher from, on the one hand, the lurid fog of anecdotal tradition that represents the stunts of an eccentric tramp at Athens and Corinth defacing conventional human standards—as he or his father, Hicesias, was supposed to have defaced in some way the currency of Sinope—or, on the other, the idealized legend that grew after his death. But doxographic traces (for example, Diogenes La...