The document discusses the ethical theories of Socrates, Plato, and Aristotle. Socrates believed virtue was found in human relationships rather than material gains. Plato advocated a virtue-based conception of ethics focused on eudaimonia, or well-being. He believed in the immortality of the soul. Aristotle defined ethics as the study of how to live well and identified happiness as the highest aim achieved through virtues. His theory emphasized naturalism and self-realization.