There are two classes of people in the world: the spectators of life and the students of life. The former class may be compared to those people who go to the theater and see acted either comedy or tragedy, and are moved by it to laughter or tears. The latter may be compared to those who go up in an aeroplane and view at a glance a whole city where hitherto they had only seen one street at a time. The students of life understand the reason of the comedy and tragedy, while the spectators of life get only a passing impression of them.