Uncertainty's a term used in subtly different ways in a number of fields, including philosophy, physics, statistics, economics, finance, insurance, psychology, sociology, engineering, and information science. It applies to predictions of future events, to physical measurements already made, or to the unknown. Concepts In his seminal work Risk, Uncertainty, and Profit University of Chicago economist Frank Knight (1921) established the important distinction between risk and uncertainty: » "Unce… (More on Uncertainty)