Major Philosophers of the time include:
| Socrates (464 – 399 B.C.) Greek
Plato (c. 428 – 348 B.C.) Greek
|Diogenes of Sinope (c. 412 – 323 B.C.) Greek
Aristotle (384 – 322 B.C.) Greek
Socrates developed a system of critical reasoning in order to work out how to live properly and to tell the difference between right and wrong. He and his followers, Plato and Aristotle maintained an unwavering commitment to the truth, and between them they organized and systematized most of the problems of philosophy.
Important philosophical movements of the period include Cynicism, Hedonism, Platonism and Aristotelianism.