 The central idea behind the theory of nonconceptual mental content is that some mental states can represent the world even though the bearer of those mental states need not possess the concepts required to specify their content. This basic idea has been developed in different ways and applied to different categories of mental state. Not all of these developments and applications are consistent with each other, but each offers a challenge to the widely held view that the way a creature can represent the world is determined by its conceptual capacities.