Philosophy final in a class for philosophy, the teacher looks at his class, grabs his chair, places it on his desk and tells the entire classroom about his final. ""You have only one question: use your knowledge that I have taught you in this class and prove to me that this chair doesn't exist. You have until the end of class."" Now while everyone else in the class worked on long complicated answers to his problem, one student got up from his desk almost as soon as it begun. The student smiles and hands the teacher his paper and was off. The teacher, almost sad that the student didn't even try, looked at the sheet of paper and gave the student an ""A"" His answer: What chair?