There was once a certain magician who had great treasures that he wished to give away, but he wanted to give them only to people who would appreciate them. He studied the matter carefully, and decided to try an experiment. He built a house, and in it there was a room in which he put all that was precious in his treasury.

Then he left the house open, so that people could come in and explore.

While the magician secretly watched, people came and wandered through the house, but to the magician’s disappointment, many people did not even notice the door to the treasure room.

Some opened the door to the room, and complained, for all they saw was a wall of brick there. Why, they demanded, would someone install a door that led only to a solid wall?

Others opened the door, looked in, decided that the room was empty, and went away again to visit more interesting parts of the house.  

Only a few went into the room and never emerged from it. They simply disappeared. 

Then the magician was satisfied that some had found what he had wished to give away.