Professor talking to his class: "The things that are real in life are verified by our perception of them through the five senses, seeing, hearing, smelling, tasting, and touching. Have you ever seen, heard, smelled, touched or tasted god? i rest my case. There is no GOD."

Student stands up and says: Professor, have you ever seen, heard, smelled, touched or tasted your brain? *faces the rest of class* i rest my case. our professor doesn't have a brain.