In his memoirs, Barack Obama explains that early in his presidency he realized that the problems that arrived on his desk had no solution. If they did, any of the clever persons that stood below him in the chain of command would have found it. We all face problems without an easy solution. Regardless of whether you are thinking about a career choice, a medical operation, or choosing a mortgage, we live in uncertainty and whether we like it or not, we have to deal with it. So how did Obama solve his problems? He learnt to think in probabilities and to choose. In fact, what Obama did was to solve problems of decision under uncertainty.