The conception of a modular structure of mind, which postulates that the mind is composed of more or less autonomous subsystems, is widespread in contemporary psychology. Proponents of a modular structure of the mind, such as Marshall (1980; 1984; 1985), Fodor (1983), Gardner (1983), and Shallice (1988), have linked their work to F. J. Gall's theory of organology or of the “functions of the brain”. This paper argues: (1) Gall's organology defends a view of the capacities of the mind that (...) relies on a specific relation between the organism and its organs. The organs of Gall stem from and originate “needs” so that they embody not so much processing capacities, but perception-for-action cycles. (2) Modules and organs arise at different levels of description that cannot be easily matched. (3) It is just this central distinction between organs and modules which explains the inherent relation between organology, comparative biology and differential psychology on the one hand and modularity and cognitive science on the other. (shrink)