While millions knew Carl Sagan from television, his students at Cornell University experienced his philosophy firsthand. He famously taught an undergraduate introductory seminar where the entire grade depended on challenging assumptions. The unwritten rule was simple: students could earn an “A” for completely disagreeing with Sagan on a scientific or philosophical point, provided they used strict empirical logic to support their claim. The lesson was intellectual humility. Sagan would deliberately present a convincing but flawed scientific argument, wait to see who blindly accepted it because of his authority, and then dismantle it to show how easily the human mind can be swayed by a famous title or confident delivery.