Rational choice, functional selection and empty black boxes

In order to vindicate rational-choice theory as a mode of explaining social patterns in general - social patterns beyond the narrow range of economic behaviour - we have to recognize the legitimacy of explaining the resilience of certain patterns of behaviour: that is, explaining, not necessarily why they emerged or have been sustained, but why they are robust and reliable. And once we allow the legitimacy of explaining resilience, then we can see how functionalist theory may also serve us well in social science; we lose the basis - the empty black box argumenton which the rational-choice critique of the theory has mostly been grounded.