In this chapter we consider how the human mind develops, and the general structure of its organisation. There has been a great deal of fruitful research in this area, but there is much more yet to be done. A fully detailed survey is far beyond the scope of a short book, let alone a single chapter. But one can set out and defend certain guiding principles or research programmes. We will be emphasising the importance of nativism and modularity.

We use the term ‘nativism’ to signify a thesis about the innateness of human cognition which does justice to the extent to which it is genetically pre-configured, while being consistent with the way in which psychological development actually proceeds. In terms of structure, we maintain that the human mind is organised into hierarchies of sub-systems, or modules. The chief advocate of the modularity of mind has been Fodor (1983), but our version of the modularity thesis is somewhat different from his. In one respect it is more extreme because we do not restrict the thesis of modularity to input systems, as Fodor does. But on the other hand, we think one needs to be a little more relaxed about the degree to which individual modules are isolated from the functioning of the rest of the mind.

The point of these disputes about the nature of modularity should become clearer as we go on. It ought to be stressed, however, that we think of modules as a natural kind – as a natural kind of cognitive processor, that is – and so what modules are is primarily a matter for empirical discovery, rather than definitional stipulation.