The Giants of Philosophy tells you all you want to know about Plato and Aristotle: Plato (circa 428-348 BC) was the first great philosopher of the West. To Plato, human beings consist of an immortal soul together with a body that keeps it in the twilight world of changing, perishing things. The ideal government, Plato believed, must reflect the...
structure of the human soul, guided by those with sure knowledge of the good, and guarded by individuals with a fierce allegiance to justice. Aristotle, known as 'the Philosopher' by later thinkers, created a huge body of work that was virtually synonymous with philosophy for over 200 years.
His most well-known doctrines include the notions that morally virtuous people seek moderation in all things, and that happiness is found not in mere pleasure, but in fully developing the powers of the soul in pursuit of excellence throughout a lifetime.