Cratylus (Κρατύλος) is the name of a dialogue by Plato, written in approximately 360 BC. In the dialogue, Socrates is asked by two men, Cratylus and Hermogenes, to tell them whether names are "conventional" or "natural", that is, whether language is a system of arbitrary signs or whether words have an intrinsic relation to the things they signify. In doing this, Cratylus became one of the earliest philosophical texts of the Classical Greek period to deal with matters of etymology and linguistics.
Plato was a philosopher in Classical Greece. He was also a mathematician, student of Socrates, writer of philosophical dialogues, and founder of the Academy in Athens, the first institution of higher learning in the Western world. Along with his mentor, Socrates, and his most-famous student, Aristotle, Plato helped to lay the foundations of Western philosophy and science. Alfred North Whitehead once noted: "the safest general characterization of the European philosophical tradition is that it consists of a series of footnotes to Plato."