Note 62 — Chapter XXXI · KRATYLUS.
Reading edition
Plato, Kratyl. pp. 428 B, 440 E.
It appears that on this point the opinion of Herakleitus coincided with that of the Pythagoreans, who held that names were φύσει καὶ οὐ θέσει and maintained as a corollary that there could be only one name for each thing and only one thing signified by each name (Simplikius ad Aristot. Categ. p. 43, b. 32, Schol. Bekk.).
In general Herakleitus differed from Pythagoras, and is described as speaking of him with bitter antipathy.