The philosopher who cannot teach something valuable in a simple way to an ordinary man should retire. Perhaps in no other field is clarity a more necessary quality, and a more evident manifestation of mastery over the subject matter. There are many forgivable sins, and many defects that even scratch the thought of a philosopher; but from the moment that discourse, through him, makes the subject more confusing, the best he would do is to return quietly to his studies, if not abandon them forever and seek a new occupation.