"Fancy what a game at chess would be if all the chessmen had passions and intellects, more or less small and cunning; if you were not only uncertain about your adversary's men, but a little uncertain also about your own; if your knight could shuffle himself on to a new square by the sly; if your bishop, in disgust at your castling, could wheedle your pawns out of their places; and if your pawns, hating you because they are pawns, could make away from their appointed posts that you might get checkmate on a sudden. You might be the longest-headed of deducted reasoners, and yet you might be beaten by your own pawns. You would be especially likely to be beaten, if you depended arrogantly on your mathematical imagination, and regarded your passionate pieces with contempt. Yet this imaginary chess is easy compared with the game a man has to play against his fellow-men with other fellow-men for his instruments. He thinks himself sagacious, perhaps, because he trusts no bond except that of self-interest; but the only self-interest he can safely rely on is what seems to be such to the mind he would use or govern. Can he ever be sure of knowing this?"