Anaxagoras was born in Clazomenae in Ionia (the land of the Milesians) around 500 BCE Like his Milesian predecessors, he was a busy public figure. For thirty years he lived in Athens, where he was the first philosopher to become a well-known teacher in the city that would soon become the hotbed of philosophy. Among his students were the dramatist Euripides and the famous Athenian politician Pericles. His association with Pericles ended up getting him in trouble; In 450 BCE (or 430 BCE, some sources vary) he was prosecuted for impiety by the Athenian state (like Socrates and Aristotle after him), an event that was probably orchestrated by political enemies of Pericles. Popular outcry against Anaxagoras was heated, fueled in large part by his declaration that the sun was not a god but a hot mass of molten rock, larger than the Peloponese. He was convicted of atheism and exiled to the northern Ionian city of Lampascus, near Troy. He died there in 428 BCE.


Aristophanes was a playwright who wrote plays between 427 to 387 BCE. He lived in the time of Socrates and Thucydides, a generation behind Sophocles and Euripides. Aristophanes produced at least forty plays, eleven of which have survived to modern times, including The Clouds, which parodies Socrates. Many of Aristophanes’ plays offer social satire or commentary. Little is known about his life beyond the work that he produced, though Plato did include Aristophanes as a character in The Symposium.


Socrates’ friend who received the prophecy from the Oracle of Delphi that proclaimed that there was no one wiser than Socrates.


The chief accuser of Socrates, responsible for bringing him to trial. Little is known about Meletus and by all accounts, he seems to have been a rather insignificant figure. Plato's portrayal of him, both in The Apology and in The Euthyphro is far from sympathetic. Socrates' cross examination of him in The Apology puts Meletus to shame.

The Oracle of Delphi

An oracle is a person who serves as a medium for receiving prophecies or advice from the gods. The oracle of Apollo at Delphi was the most famous and most revered oracle of the ancient world. The oracle declared Socrates to be “the most free, upright, and prudent of all people” rather than the most wise. In either case, the oracle made a positive claim about Socrates. Also of relevance to The Apology is the famous motto inscribed above the entrance to the oracle at Delphi: “Know thyself.”


The protagonist of The Apology, as well as all of Plato's other dialogues. Socrates seems to be a very simple man, not having many material possessions and speaking in a plain, conversational manner. However, this seeming plainness is all a part of the ironic characteristic of Socrates' method. Professing his own ignorance, he engages in conversation with someone claiming to be an expert, usually in ethical matters. By asking simple questions, Socrates gradually reveals that his interlocutor is in fact very confused and does not actually know anything about the matters about which he claimed to be an expert. The quest for wisdom and the instruction of others through dialogue and inquiry were considered by Socrates to be the highest aims in life: one of his most famous sayings is, “The unexamined life is not worth living.”

Some have argued that Socrates himself never advanced any theories of his own, and certainly many of the doctrines that appear in the later dialogues are of Plato's invention. In early dialogues, such as The Apology, Plato presents us with a Socrates who is less informed by Platonic philosophy and serves more as foil for his interlocutors who claim to have positive knowledge.

The Sophists

The Sophists were teachers-for-hire who educated the wealthy men of Athens in the fifth century BCE. Though they were a diverse group with varying opinions, they tended to share a disregard for the notion of objective truth and knowledge. This disregard extended to the notion of objective moral truth, which means that they did not believe in such things as “right” and “wrong.” One of the guiding motivations in all of Plato’s work was to prove the Sophists wrong: to show that there is such a thing as objective truth, and that we can have knowledge of this objective truth.