From John Hale’s Lords of the Sea, The Epic Story of the Athenian Navy and the Birth of Democracy (p. 113):

“In Athens haircuts and hairstyles had social and political implications. Aristocratic horsemen still wore long braids and gold hairpins. The common man (and the politicians who spoke for him) preferred a short cut, though not quite a crew cut. The customer sat on a low stool, his body draped in a sheet to catch the shorn locks. The barber then cropped and curled the hair, anointed the head with scented oil, and trimmed the beard to a neat point. (At Athens any man with a long unkempt beard ran the risk of being mistaken for a philosopher).”

The gods forbid.

Notes the Dictionary of Greek and Roman Antiquities: Among the Greeks a beard was a sign of manliness (after all, only women and youths are beardless), and longer beards had become a status symbol of philosophers, giving rise to the common saying “A long beard does not make a philosopher” (πωγωνοτροφία φιλόσοφων οὐ ποιεῖ or Barba non facit philosophum).

The Latin version of the phrase takes us to Rome, where later many Romans shaved their beards in order not to be taken for Greeks, Greek influence sometimes being politically suspect. The paranoid emperor Domitian once ordered philosophers to be banished from Rome, and many shaved their beards to disguise their profession.

Stoic philosopher Epictetus wrestled lightly with the dilemma and, in a small act of defiance, refused to shave: “Come, then, Epictetus, shave yourself.” “If I am a philosopher, I will not shave myself” (page 10 of this edition of the Discourses).

Domitian was assassinated in the year 96. Coincidence?

All of which makes one wonder about the true significance of Ockham’s Razor and our professional preoccupation with Bertrand Russell’s Barber Paradox.

A side note: Michael Gilleland has lines from ancient poets making fun of beards, especially philosophers’ beards.