Smartest man on Earth?

Question: A quantum physicist is conducting a seminar in the campus auditorium at California's Institute of Technology. Half way through it, a man dressed as a clown walks in. The man steps up to the podium and announces that he is able to answer any question about anything correctly and without hesitation. The professor asks if he is a physicist & the man says he is not. He is then asked his profession. He says that he is a clown for hire. Everyone laughs. The professor accepts the challenge and asks the man a series of difficult questions. The man answers each one correctly. Then the students began to ask the man questions. No matter what he was asked, he always had a correct answer. How did he do it?