 Does he make the move because he believes that it is a strong one, or because out of charity to his opponent, he doesn’t want to make a strong one? The distinction here between a belief and a want (attitude) is certainly beyond any practical objection. One can imagine the expert, with constant beliefs about the opening, using it or not in accordance with his changing desires to win; or one can imagine him, with constant desires to win, using it or not in accordance with his changing beliefs. (1944, 7–8)