Or 'skill is the servant of the arts' if you will. It's a play on two meanings of 'ars'. In one sense it is a skill, technique or knack and in the other art , here' the arts'. So the saying reminds us that art requires technical skill to be created and the artist is no artist without mastering it or having craftsmen to carry it out on instructions ; on the other hand pure dexterity, the craftmanship, is of no value without the art to direct it.