Abstract
This chapter defends the positive thesis which constitutes its title. It argues first, that the mind has been shaped by natural selection; and second, that the result of that shaping process is a modular mental architecture. The arguments presented are all broadly empirical in character, drawing on evidence provided by biologists, neuroscientists and psychologists (evolutionary, cognitive, and developmental), as well as by researchers in artificial intelligence. Yet the conclusion is at odds with the manifest image of ourselves provided both by introspection and by common-sense psychology. The chapter concludes by sketching how a modular architecture might be developed to account for the patently unconstrained character of human thought, which has served as an assumption in a number of recent philosophical attacks on mental modularity