Socrates
(c. 469 BC-399 BC) We have no writings from his own hand, and know about him largely from the dialogues of his student Plato. Proclaiming his own ignorance of all things, he went around Athens engaging in question-and-answer sessions to search for truths
Plato
(c. 429 BC-347 BC) His Socratic dialogues are our main source both for Socrates's philosophy and his own; He often put his own thoughts in Socrates' mouth. His dialogues include the Republic (about justice and the ideal city-state), the Symposium (about t
Aristotle
(c. 384 BC-322 BC) He was a student of Plato; in turn, he was a tutor to Alexander the Great. Many of his works come to us in the form of lectures he gave at his school, known as the Lyceum. His philosophical output includes the Nicomachean Ethics, which
Confucius
(or Kong Fu Zi) (6th century BC) A pivotal thinker from China's Spring and Autumn period, his views on proper conduct and filial piety influence China to this day. Many sayings attributed to him were compiled by his disciples following his death in a text
Lao Tzu
(also given as Lao Tse or Laozi) (dates unknown, 6th century BC) is a quasi-mythical thinker of the Taoist tradition, to whom the pivotal Tao te Ching is attributed. Concepts associated with him include that of the Tao, or "the way," and wu wei, or a life
Diogenes
(c. 410s BC-323 BC) He was a student of Antisthenes, who founded the ancient school of philosophy known as Cynicism. (The term "cynic" comes from the Greek for "dog-like," and is thought to have originated as an insult to the school's members.) The Cynics
Epicurus
(341 BC-270 BC) His namesake school, Epicureanism, believed that pleasure was the highest (or only) good, and that the absence of pain (aponia) was the highest pleasure. They also believed that human happiness consisted of a kind of tranquillity known as
Zen of Elea
(c. 490 BC-430 BC) He was a student of Parmenides, who founded the Eleatic school in a Greek colony of the Italian peninsula. He is most famous today for his namesake paradoxes the best-known of which involve an arrow in flight and a race between Achilles
Thales
(c. 620 BC-546 BC) He was a pre-Socratic thinker from the Greek colony of Miletus who many consider to be the "first philosopher." Rejecting mythical explanations of the universe's nature, he believed that the first principle of all existence, the natural
Cicero
(106 BC-43 BC) Though he is better remembered today for his role in the political life of the Roman Republic, he (sometimes known as "Tully") was also a significant philosopher. He described the ideal state in such dialogues as On the Republic and On the