What comprises good performance? The ability through singing or playing to make the ear conscious of the true content and affect of a composition.
A musician cannot move others unless he too is moved. He must of necessity feel all of the affects that he hopes to arouse in his audience, for the revealing of his own humour will stimulate a like humour in the listener.
According to my principles, every master has his true and certain value. Praise and criticism cannot change any of that. Only the work itself praises and criticizes the master, and therefore I leave to everyone his own value.