To illustrate this, let us suppose two teachers wishing to explain to their pupils the same subject, and taking the following opposite methods of doing it.  One, at the close of school, addresses his charge as follows: 

“The moral character of any action, that is, whether it is right or wrong, depends upon the motives with which it is performed.  Men look only at the outward conduct, but God looks at the heart.  In order, now, that any action should be pleasing to God, it is necessary it should be performed from the motive of a desire to please him.

“Now there are a great many other motives of action which prevail among mankind besides this right one.  There is love of praise, love of money, affection for friends, and many others.”

By the time the teacher has proceeded thus far, he finds, as he looks around the room, that the countenances of his pupils are assuming a listless and inattentive air.  One is restless in his seat, evidently paying no attention.  Another has reclined his head upon his desk, lost in a reverie, and others are looking round the room at one another, or at the door, restless and impatient, hoping that the dull lecture will soon be over.

The other teacher says: 

“I have thought of an experiment I might try, which would illustrate to you a very important subject.  Suppose I should call one of the boys, A, to me, and should say to him, ’I wish you to go to your seat, and transcribe a piece of poetry as handsomely as you can.  If it is written as well as you can possibly write it, I will give you a quarter of a dollar.  Suppose I say this to him privately, so that none of the rest of the boys can hear, and he goes to take his seat and begins to work.  You perceive that I have presented to him a motive to exertion.”

“Yes, sir,” say the boys, all looking with interest at the teacher, wondering how this experiment is going to end.

“Well, what would that motive be?”

“Money.”  “The quarter of a dollar.”  “Love of money,” or perhaps other answers, are heard from the various parts of the room.

“Yes, love of money it is called.  Now suppose I should call another boy, one with whom I was particularly acquainted, and who I should know would make an effort to please me, and should say to him, ’For a particular reason, I want you to copy this poetry’—­giving him the same—­’I wish you to copy it handsomely, for I wish to send it away, and have not time to copy it myself.  Can you do it for me?’

“Suppose the boy should say he could, and should take it to his seat and begin, neither of the boys knowing what the other was doing.  I should now have offered to this second boy a motive.  Would it be the same with the other?”

“No, sir.”

“What was the other?”

“Love of money.”

“What is this?”

The boys hesitate.

“It might be called,” continues the teacher, “friendship.  It is the motive of a vast number of the actions which are performed in this world.