The assumption that actors maximize subjective expected utility (economic rationality) supplies only a small part of the premises in economic reasoning, and that often not the essential part. The remainder of the premises are auxiliary empirical assumptions about actors' utilities, beliefs, expectations, and the like. Making these assumptions correctly requires an empirically founded theory of choice that specifies what information decision makers use and how they actually process it. This behavioral empirical base is largely lacking in contemporary economic analysis, and supplying it is essential for enhancing the explanatory and predictive power of economics.