Antisthenes

Antisthenes was a devoted companion of Socrates, present at his death, who took from his master the conviction that virtue is the only true good and is sufficient by itself for happiness. From this he drew an austere, ascetic ethic, scorning wealth, reputation, and pleasure as worthless, and prizing self-mastery and a life lived 'according to nature'.

In this severity later ages saw the seed of Cynicism, and reckoned Antisthenes its founder and the teacher of Diogenes of Sinope. He also argued, against Plato, that the universal Forms are not real things but only names — an early nominalism.