In the classroom, subjects are often presented as settled and complete. But our collective understanding of any given subject is never complete, according to Jamie Holmes, who has just written a book on the hidden benefits of uncertainty. In Nonsense: The Power of Not Knowing, Holmes explores how the discomforting notions of ambiguity and uncertainty affect the way we think and behave. Confronting what we dont know sometimes triggers curiosity. Teachers who hope to inspire curiosity in their students, and to encourage tolerance for ambiguity, can take steps to introduce uncertainty into the classroom. The emotions of learning are surprise, awe, interest and confusion, Holmes said. But because confusion provokes discomfort, it should be discussed by teachers to help students handle the inevitable disquiet. The best assignments should make students make mistakes, be confused and feel uncertain, he said. Teachers who instruct with a sense of humanity, curiosity and an appreciation for mystery are more apt to engage students in learning, Holmes explained. Those with an outlook of authority and certainty dont invite students in, he said. Also, when teachers present themselves as experts imparting wisdom, students get the mistaken idea that subjects are closed. Teachers should help students find ways to think and learn, he said. The best teachers are in awe of their subjects. The process of discovery is often messy and non-linear.