Full Idea
Cratylus thought speech of any kind was radically inappropriate and that expression should be restricted exclusively to the movement of the finger.
Gist of Idea
Cratylus decided speech was hopeless, and his only expression was the movement of a finger
Source
report of Cratylus (fragments/reports [c.425 BCE]) by Aristotle - Metaphysics 1010a
Book Reference
Aristotle: 'Metaphysics', ed/tr. Lawson-Tancred,Hugh [Penguin 1998], p.101