Wise Men Speak Because They Have

This aphorism is widely attributed to Plato but does not appear in this form in any surviving dialogue. The distinction between purposeful speech and compulsive speech runs through several dialogues: in the Symposium, Phaedrus and others speak because they have something genuine to contribute, while less thoughtful characters speak merely from social impulse. The closest thematic parallel is in the Phaedrus (277b–278a), where Plato distinguishes writing worth preserving from mere "showing off." The quote as given is likely a later condensation, popularised in commonplace books.