What will be the good of the conquest of leisure and health, if no one remembers how to use them? The war against physical evil, like every other war, must not be conducted with such fury as to render men incapable of the arts of peace. What the world possesses of ultimate good must not be allowed to perish in the struggle against evil.
Source: On Education, especially in early childhood, 1926, chap. 1:Postulates of modern educational theory.