History of ethics in Ancient Greece
Ethical theory in Greek culture predates philosophical reflection. The main ethical category for ancient Greeks was aretē, which is usually translated into English as "virtue" but sometimes as "excellence," which is closer in meaning. Aretē means an excellence of strength or ability, and is ultimately bound up with the notion of the fulfillment of purpose or function: the act of living up to one's full potential. The objective of a successful life was attaining timē, or honor. Also an important concept in Greek culture was that of hybris, trying to go beyond one's possibilities. The literary source of this folk ethical theory can be seen in Homer, Greek tragedy and also Aesop's fables.
The first philosophers, the Presocratics, occasionally reflected on ethics. Heraclitus thought that injustice appears only in the eyes of men, and that a divine perspective would show that everything is just. Pythagoras founded a sect in which a good reincarnation (metempsychosis) was to be attained through following certain ascetic practices. Democritus proposed cheerfulness as the supreme goal of life.
An important change came with the Sophist movement, who resembled professional teachers. They traveled from one city to another, and were concerned with ethical problems. Protagoras was a sophist and the first formulator of relativism in Western thought. By saying man is the measure of all things, he attacked the unchallenged notion of a fixed reality.
Socrates was a milestone in the history of ethics. He regarded for the first time aretē as the rational part of the human soul/mind (psychē).