The teacher was vividly describing the discovery of the law of gravitation, hoping to impress upon the children its significance.
He said, "Isaac Newton was sitting on the ground, looking at a tree. An apple suddenly fell on his head, which led him to discover gravity." He added, "Isn't that wonderful?"
The "smart boy" in the class replied loudly, "Yes, teacher, and he was very fortunate. If he had been looking at his books, he wouldn't have discovered anything."