Glaucon: The Ancient Greek Philosopher and Plato’s Older Brother

Ancient Greek philosopher Glaucon was the older brother of Plato, and appeared in many Platonian works. He was famous and admired in his own right, too.

The ancient Greek philosopher Glaucon was thought to have lived in the latter half of the 5th century BC, and is known primarily by modern-day readers for his conversations with Socrates in Plato’s Republic.

Glaucon’s family lived in the district of Collytus, just outside of Athens. His father was Ariston, who, according to some ancient Greek scholars, traced his descent from the King of Athens, Codrus, and the King of Messenia, Melanthus. Codrus himself was believed to be a demigod fathered by the god of the sea Poseidon.

The mother of Glaucon and Plato, Perictione, came from a family that had a close relationship with the famous Athenian lawmaker and lyric poet Solon.

Most notably, in book two of Plato’s Republic, Glaucon introduces a concept know as the Ring of Gyges, a ring which, when worn by its owner, grants them the power to become invisible at will. During this section of Plato’s Republic, it is considered whether a rational, intelligent person who will not come up against any negative consequences, would still act justly.

Glaucon specifically asks whether any man could be so virtuous that he was able to resist the temptation of killing, robbing, raping or generally carrying out injustice, knowing that he would never be caught.

Glaucon wants Socrates, who he is questioning at this point, to argue that it is beneficial for humans to be just, even when it has no perceived benefit for their reputation.

“All men believe in their hearts that injustice is far more profitable to the individual than justice, and he who argues as I have been supposing, will say that they are right. If you could imagine any one obtaining this power of becoming invisible, and never doing any wrong or touching what was another’s, he would be thought by the lookers-on to be a most wretched idiot, although they would praise him to one another’s faces, and keep up appearances with one another from a fear that they too might suffer injustice,” Glaucon says in the Republic.

Aside from philosophical musings and dialectical jousting, certain facts come out of Plato’s Republic in regard to his older brother.

Some of the Facts about Glaucon

One historian suggests that two major things about Glaucon’s life can be understood through a comment made by Socrates; that Glaucon was old enough to have gained fame in the Battle of Megara, and that he was the eromenos (adolescent boy courted by older man) of the poet and statesman Critias. Another of Socrates’ comments helps us to ascertain that Glaucon also owned property where he kept and bred sporting dogs and game birds.

Glaucon is also referenced briefly in the early portions of two other dialogues by his younger brother, the Parmenides and Symposium, and he makes another appearance in ancient Greek philosopher Xenophon’s Memorabilia.

Aristotle makes mention of him in his colossal work Poetics, too, arguing against one of Glaucon’s theories and writing, “The true mode of interpretation is the precise opposite of what Glaucon mentions. Critics, he says, jump at certain groundless conclusions; they pass adverse judgement and then proceed to reason on it; and, assuming that the poet has said whatever they happen to think, find fault if a thing is inconsistent with their own fancy.”

Dioegenes Laertius, a renowned biographer of the ancient Greek philosophers, attributed nine dialogues to Glaucon, including Phidylus, Euripides, Amyntichus, Euthias, Lysithides, Aristophanes, Cephalus, Anaxiphemus, and Menexenus, however, no trace of these works remains.

A Recent Mention of the Philosopher

Glaucon was also mentioned by US Secretary of State Anthony Blinken during a meeting between him and Greece’s Minister of Foreign Affairs Georgios Gerapetritis, last week, where Greece signed the Artemis Accords. The US Secretary of State said, “As the early Greek philosopher Glaucon put it, and I quote, ‘Astronomy compels the soul to look upwards and leads us from this world to another.’