Ancient Philosophers

Socrates

We have no writings from this philosopher's own hand, and know about him largely from the dialogues of his student. Proclaiming his own ignorance of all things, He went around Athens engaging in question-and-answer sessions to search for truths or draw out contradictions (the "Socratic method"). The Athenian state disapproved of his conduct; he was put on trial for corrupting the city's youth, and sentenced to death by drinking hemlock. His trial, imprisonment, and death are recounted in Plato's Apology, Crito, and Phaedo, respectively.

Plato

This philosopher's Socratic dialogues are the 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 the nature of love), and the Meno (about whether virtue can be taught). He believed in a world of "forms"—or ideal versions of real things that lie beyond the human senses—which he discussed in such works as the Phaedo. He founded a school called the Academy, from which we get the common word.

Aristotle

This philosopher was a student of Plato and 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 argues that virtues consist in a "golden mean" between two extremes; the Physics, which describes motion and change in terms of "four causes" that make a given thing what it is; and the Metaphysics, which describes the structure of reality. His Poetics discusses the types of drama and considers an effect of tragedies known as catharsis, or the purging of bad feelings.

Confucius

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 known as the Analects. This philosopher put much importance on ren, the inner state which allows one to behave compassionately toward others, and on a concept called li, which can help individuals attain ren.

Lao Tzu

This philosopher was 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 of non-action in accordance with the Tao. In later centuries, he was accorded godlike status as one of the Three Pure Ones of Taoism, and is frequently depicted as an old man with a donkey. He is attributed the quote "The journey of a thousand miles begins with a single step."

Diogenes

This philosopher 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 rejected conventional social norms in search of a truly virtuous life. He himself was something of an eccentric—according to legend, he lived in a tub or a barrel on the street, and wandered Athens holding a lamp in his futile search for an honest man.

Epicurus

This philosopher's namesake school 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 ataraxia. Critics accused his school of promoting hedonism and making selfishness into a good, though they did not believe themselves to be hedonists.

Zeno of Elea

This philosopher was a student of Parmenides, who founded the Eleatic school in a Greek colony of the Italian peninsula. He is most famous today for a group of paradoxes, which are named after him, the best-known of which involve an arrow in flight and a race between Achilles and a tortoise. His paradoxes purport to show that physical movement is impossible, since any attempt to travel a distance must be preceded by moving half that distance, which must be preceded by moving half of half that distance, and so on.

Thales

This philosopher 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 element from which all things emerged, was water. He was also a civil engineer and mathematician, and is credited with discovering that if a circle goes through all three vertices of a triangle and one side of the triangle is a diameter of the circle, then the triangle is a right triangle. He is sometimes thought of as the founder of a "Milesian school" of philosophy, whose other members include Anaximander and Anaximenes.

Cicero

Though he is better remembered today for his role in the political life of the Roman Republic, this important public speaker (sometimes known as "Tully") was also a significant philosopher. He described the ideal state in such dialogues as On the Republic and On the Laws, while he discussed Epicurean and Stoic views on religion in On the Nature of the Gods. Through the Middle Ages and Renaissance, he was considered one of the most important of ancient philosophers. Indeed, Saint Augustine asserted that he turned to philosophy as a result of reading a now-lost work by him known as the Hortensius.