Carruthers, PeterThis paper starts from an assumption defended in the author’s previous work. This is that distinctively-human flexible and creative theoretical thinking can be explained in terms of the interactions of a variety of modular systems, with the addition of just a few a-modular components and dispositions. On the basis of that assumption it is argued that distinctively human practical reasoning, too, can be understood in modular terms. The upshot is that there is nothing in the human psyche that requires any significant retreat from a thesis of massively modular mental organization.en-UStheoretical thinkingmodular systemsa-modular componentsdispositionspractical reasoningmassively modular mental organizationArticle