Diogenes of Sinope (l. c. 404-323 BCE) was a Greek Cynic philosopher best known for holding a lantern (or candle) to the faces of the citizens of Athens claiming he was searching for an honest man. He rejected the concept of "manners" as a lie and advocated complete truthfulness at all times and under any circumstance.
He was most likely a student of the philosopher Antisthenes (l. 445-365 BCE, who studied with Socrates) and, in the words of Plato (allegedly), was “A Socrates gone mad.” He was driven into exile from his native city of Sinope for defacing currency (though some sources say it was his father who committed the crime and Diogenes simply followed him into exile). He made a home for himself in Athens in the agora, living in a rain barrel and surviving off gifts from admirers, foraging, and begging.
Diogenes famous "search for an honest man" was his way of exposing the hypocrisy and sham of polite societal conventions. By holding a literal light up to people's faces in broad daylight, he forced them to recognize their participation in practices that prevented them from living truthfully. He inspired others to follow his example, most notably Crates of Thebes (l. c. 360 - 280 BCE) who studied with him. Diogenes is still highly regarded in the present day for his commitment to truth and living according to his beliefs.
Diogenes came to Athens where he met Antisthenes (one of many of Socrates' students who established his own school) who at first refused him as a student but, eventually, was worn down by his persistence and accepted him. Like Antisthenes, Diogenes believed in self-control, the importance of personal excellence in one's behavior (in Greek, arete, usually translated as `virtue'), and the rejection of all which was considered unnecessary in life such as personal possessions and social status.
He was so ardent in his beliefs that he lived them very publicly in the market place of Athens. He took up residence in a large wine cask (some sources claim it was an abandoned bathtub), owned nothing, and seems to have lived off the charity of others. He owned a cup which served also has a bowl for food but threw it away when he saw a boy drinking water from his hands and realized one did not even need a cup to sustain oneself.
This much can be said with more or less assurance but any other details become increasingly uncertain owing to the many fables which grew up around Diogenes and his time in Athens. Even the claim that he was Antisthenes' student has been challenged as a fable. It seems clear, however, that Diogenes believed what people called `manners' were simply lies used to hide the true nature of the individual.
He was known for brutal honesty in conversation, paid no attention to any kind of etiquette regarding social class, and seems to have had no problem urinating or even masturbating in public and, when criticized, pointed out that such activities were normal and that everyone engaged in them but hid in private what he did openly.
According to Diogenes, society was an artificial contrivance set up by human beings which did not accord well with truth or virtue and could not in any way make someone a good and decent human being; and so follows the famous story of Diogenes holding the light up to the faces of passers-by in the market place looking for an honest man or a true human being. Everyone, he claimed, was trapped in this make-believe world which they insisted was reality and, because of this, people were living in a kind of dream state.
He was not the first philosopher to make this claim; Heraclitus, Xenophanes, and, most famously, Socrates all pointed out the need for human beings to wake from their dream state to full awareness of themselves and the world. Plato's famous Allegory of the Cave is devoted to this very theme. Diogenes, however, confronted the citizens of Athens daily with their lifelessness and shallow values, emulating his hero Socrates whom he never met but would have learned of from Antisthenes. Although it seems many people thought he was simply mentally ill, Diogenes would have claimed he was living a completely honest life and others should have the courage to do the same.
Plato & Alexander the Great
This behavior of Diogenes was informed in part by the belief that if an act is not shameful in private then it should not be shameful in public. The rules by which people lived, then, were non-sensical in that they forced people to behave in a way different from how they would naturally have behaved. Manners and etiquette were both regarded by him as staples of the false life in the dream world and should not be indulged in.
Accordingly, he insulted his social superiors regularly, including Plato and Alexander the Great. When Plato defined a human being as "a featherless biped", and was praised for the cleverness of the definition, Diogenes plucked a chicken, brought it to Plato's Academy, and declared, "Behold - Plato's human being." Plato then added "with broad, flat, nails" to his definition. This is not the only time Diogenes insulted Plato publicly but is the best known incident.
In the case of Alexander the Great, both Diogenes Laertius (l. c. 180-240 CE) and Plutarch (l. 45/50-120/125 CE) relate how, when Diogenes was living in Corinth, Alexander came to the city and was very interested in meeting the philosopher. He found Diogenes resting in the sunlight, introduced himself, and asked if there was anything he could do for him. Diogenes replied, "Yes. Get out of my sunlight." Alexander admired his spirit and said, "If I were not Alexander, I would wish to be Diogenes" to which Diogenes replied, "If I were not Diogenes, I would also wish to be Diogenes."
On another occasion, when some people were discussing a man named Callisthenes and the fine treatment he received from Alexander, Diogenes said, "The man then is wretched, for he is forced to breakfast and dine whenever Alexander chooses." Another time, at a banquet for some Athenian elites, some of the guests threw Diogenes some bones and referred to him as a dog; so he lifted his leg and urinated on them. In spite of, or because of, his outrageous behavior, the Athenians loved him and, Laertius relates, when a boy broke Diogenes' cask, the people had the boy beaten and replaced the broken cask. It is unlikely, however, that Diogenes cared very much for the cask or what state it was in; to him, possessions were a trap.
To be truly free, and live a virtuous life of complete awareness, was the ultimate meaning of one's existence. As Diogenes Laertius writes:
On one occasion he was asked, what was the most excellent thing among men; and he said, `Freedom of speech.' He was in the habit of doing everything in public, whether in respect of Venus or Ceres; and he used to put his conclusions in this way to people: `If there is nothing absurd in dining, then it is not absurd to dine in the market-place. But it is not absurd to dine, therefore it is not absurd to dine in the market-place'.
This was in reference to the prohibition on eating in the agora (the public market and communal space of the city) which, like all such prohibitions, Diogenes ignored. Laws and rules, like manners, were artificial constructs to him which only separated one from reality and a clear understanding of one's self and the world.
Slavery & Death
For Diogenes, a reasonable life is one lived in accordance with nature and with one's natural inclinations. To be true to oneself, then, no matter how `mad' one may appear, was to pursue a life worth living. Whether true or another fable, the tale of Diogenes' capture by pirates and his being sold into slavery in Corinth bears testimony to the strength of his convictions. When asked what talent he had he replied, “That of governing men” and then demanded to be sold to Xeniades saying, “Sell me to that man; for he wants a master.” Even though he was a slave at this point, and in no position to demand anything, he believed so completely in himself that others felt compelled to listen to him and do what he said.
Xeniades, for example, placed Diogenes in charge of tutoring his young sons and, in time, the philosopher became part of the family. He lived in Corinth with Xeniades' family for the rest of his life and died there at the age of ninety. His cause of death has been given as either severe food poisoning from eating a raw ox's foot, rabies from a dog bite, or suicide by holding his breath.
The citizens of Corinth, like those of Athens, had come to greatly admire the philosopher and buried him in honor by the city gate, erecting a monument over his grave. This would have amused Diogenes who, when asked what he wished done with his body after his death, replied that it should be thrown outside the city for the dogs to feed on. A statue of him stands in modern-day Sinop, Turkey, depicting him holding out his lantern with a dog sitting by his side.