Full Idea
Gorgias insists that the art of persuasion is superior to all others because it enslaves all the rest, with their own consent, not by force, and is therefore by far the best of all the arts.
Gist of Idea
Gorgias says rhetoric is the best of arts, because it enslaves without using force
Source
report of Gorgias (fragments/reports [c.443 BCE]) by Plato - Philebus 58a
Book Reference
Plato: 'Complete Works', ed/tr. Cooper,John M. [Hackett 1997], p.447
A Reaction
A nice point, and it is not unreasonable to rank the arts in order of their power. To enchant, without achieving agreement, and to speak truth without persuading, are both very fine, but there is something about success that cannot be gainsaid.