Critics of mainstream economics often argue that the mainstream does not recognize that the economy is dynamic, creative and evolving, and they base their criticism of it for its failure to recognize that. This paper argues that the mainstream does recognize that the economy is evolving, and changes its methods as new analytic technologies and computational methods develop. The paper suggests that a narrower critique of the mainstream is appropriate: It attempts to be too scientific, following a scientific rather than an engineering methodology. Thinking of applied economic policy as engineering, not science opens up new avenues of research, and will allow it be better deal with our complex world.