Kratylos

Kratylos was a follower of the teachings of Heracleitus and a member of the Ephesian school. His pupil was Plato, but only until he exchanged him for Socrates. Plato named his dialogue after him, which addresses the question of the origin of names and deals with Heracleitism. Heracleitos judged that "one cannot enter the same river twice"; Kratylos corrected him that "one cannot enter the same river even once".

Kratylus is also referred to by Aristotle in his Metaphysics.