Of progress or improvement

He who is making progress, having learned from philosophers that desire means the desire of good things, and aversion means aversion from bad things; having learned too that happiness and tranquillity are not attainable by man otherwise than by not failing to obtain what he desires, and not falling into that which he would avoid; such a man takes from himself desire altogether and defers it, but he employs his aversion only on things which are dependent on his will.