Economics today cannot predict the likely outcome of specific events any better than it could in the time of Adam Smith. This is Alexander Rosenberg's controversial challenge to the scientific status of economics. Rosenberg explains that the defining characteristic of any science is predictive improvability—the capacity to create more precise forecasts by evaluating the success of earlier predictions—and he forcefully argues that because economics has not been able to increase its predictive power for over two centuries, it is not a science.