• As for our pupils talk, let his virtue and his sense of right and wrong shine through it and have no guide but reason. Make him understand that confessing an error which he discovers in his own argument even when he alone has noticed it is an act of justice and integrity, which are the main qualities he pursues; stubbornness and rancour are vulgar qualities, visible in common souls whereas to think again, to change one's mind and to give up a bad case on the heat of the argument are rare qualities showing strength and wisdom.