Peter Carruthers

This article evaluates the scientific credentials of a distinction that is frequently endorsed by scientists who study human reasoning, between so-called “System 1” and “System 2”. The paper argues that one aspect of what is generally intended by this distinction is real. In particular, there is a real distinction between intuitive and reflective cognitive processes. But this distinction fails to line up with many of the other properties attributed to System 1 and System 2. Accordingly, the paper argues that the latter distinction is not real, and should be abandoned.

My charge in this chapter is to set out the positive case supporting massively modular models of the human mind.1 Unfortunately, there is no generally accepted understanding of what a massively modular model of the mind is. So at least some of our discussion will have to be terminological. I shall begin by laying out the range of things that can be meant by ‘modularity’. I shall then adopt a pair of strategies. One will be to distinguish some things that ‘modularity’ definitely can’t mean, if the thesis of massive modularity is to be even remotely plausible. The other will be to look at some of the arguments that have been offered in support of massive modularity, discussing what notion of ‘module’ they might warrant. It will turn out that there is, indeed, a strong case in support of massively modular models of the mind on one reasonably natural understanding of ‘module’. But what really matters in the end, of course, is the substantive question of what sorts of structure are adequate to account for the organization and operations of the human mind, not whether or not the components appealed to in that account get described as ‘modules’. So the more interesting question before us is what the arguments that have been offered in support of massive modularity can succeed in showing us about those structures, whatever they get called.