A little over one hundred years ago, a famous professor of philosophy lived and worked in an old German university in a city on the Rhine. Every day, at precisely 11:45 a.m., the professor would leave his desk, where he had been working since early morning, and walk briskly, whatever the weather, through the city zoological gardens to a restaurant, where he would have a light lunch. Sometimes he would be joined by a friend, but more often he would dine alone, with a book as his companion. One morning on his walk, he noticed a keeper in the cage of a large ape, a gorilla named Samson, who was perhaps the zoo's most famous resident. The keeper was squatting next to Samson, and there were several large sheets of paper scattered around them. The professor approached the cage, and said, "Good morning. May I ask what you are doing?" The keeper replied, "Good morning. Professor. I am seeing if I can teach this ape to draw. He seems so intelligent and responsive, so I wondered if he were capable of learning human art." He held up some sheets of paper, which were covered with a mess of crude lines. "As you can see. Professor, this may be a very clever ape. but he has no capacity for the higher human attainments, I have tried to show him the rudiments, but the best he can do is to make these badly-drawn lines," the keeper explained. "I think not," the professor replied, "since it seems to me that Samson has discovered the fundamental principle of all art." The professor looked sadly at the ape, and said, "He has drawn the bars of his cage."