A philosopher went into a closet for ten years to contemplate the question, What is life? When he came out, he went into the street and met an old colleague, who asked him where in heaven's name he had been all those years.
"In a closet," he repied. "I wanted to know what life really is."
"And have you found an answer?"
"Yes," he replied. "I think it can best be expressed by saying that life is like a bridge."
"That's all well and good," replied the colleage, "but can you be a little more explicit? Can you tell me how life is like a bridge?"
"Oh," replied the philosopher after some thought, "maybe you're right; perhaps life is not like a bridge."