Cynicism (Ancient Greek: κυνισμός) is a school of thought of ancient Greek philosophy as practiced by the Cynics (Ancient 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, and fame, and even flouting conventions openly and derisively in public. 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 BCE. He was followed by Diogenes, who lived in a ceramic jar 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 gradually declined in importance after the 3rd century BCE, but it experienced a revival with the rise of the Roman Empire in the 1st century. Cynics could be found begging and preaching throughout the cities of the empire, and similar ascetic and rhetorical ideas appeared 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.