He [Tom Sawyer] had discovered a great law ofhuman action, without knowing it—namely, that in order to make a man or a boy covet a thing, it is only necessary to make the thing difficult to attain. If he had been a great andwise philosopher, like the writer of this book, he would now have comprehended that Work consists of whatever a body is obliged to do andthat Play consists of whatever a body is notobliged to do.