You’d think that a scientist who studies how the human brain receives and perceives information would be inherently interested in what we know. But Stuart Firestein says he’s far more intrigued by what we don’t. “Answers create questions,” he says. “We may commonly think that we begin with ignorance and we gain knowledge [but] the more critical step in the process is the reverse of that.”

Firestein, who chairs the biological sciences department at Columbia University, teaches a course about how ignorance drives science. In it -- and in his 2012 book on the topic -- he challenges the idea that knowledge and the accumulation of data create certainty. Facts are fleeting, he says; their real purpose is to lead us to ask better questions.