Cynicism (Greek: κυνισμός) is a school of Ancient Greek philosophy as practiced by the Cynics (Greek: Κυνικοί, Latin: Cynici). For the Cynics, the purpose of life is to live in virtue, in agreement with nature. As reasoning creatures, people can gain happiness by rigorous training and by living in a way which is natural for themselves, rejecting all conventional desires for wealth, power, sex, and fame. Instead, they were to lead a simple life free from all possessions.
The first philosopher to outline these themes was Antisthenes, who had been a pupil of Socrates in the late 5th century BC. He was followed by Diogenes of Sinope, who lived in a tub on the streets of Athens. Diogenes took Cynicism to its logical extremes, and came to be seen as the archetypal Cynic philosopher. He was followed by Crates of Thebes who gave away a large fortune so he could live a life of Cynic poverty in Athens. Cynicism spread with the rise of Imperial Rome in the 1st century, and Cynics could be found begging and preaching throughout the cities of the empire. It finally disappeared in the late 5th century, although similar ascetic and rhetorical ideas appear in early Christianity.
By the 19th century, emphasis on the negative aspects of Cynic philosophy led to the modern understanding of cynicism to mean a disposition of disbelief in the sincerity or goodness of human motives and actions.