This paper critically examines the argument structure of Fodor's theory of modularity. Fodor claims computational autonomy as the essential properly of modular processing. This property has profound consequences, burdening modularity theory with corollaries of rigidity, non-plasticity, nativism, and the old Cartesian dualism of sensing and thinking. However, it is argued that Fodor's argument for computational autonomy is crucially dependent on yet another postulate of Fodor's theory, viz. his thesis of strong modularity, ie. the view that functionally distinct modules must also (...) have physical counterparts in the neural architecture of the brain. Yet, Fodor offers little or no independent support for this neurological speculation. Moreover, due to the cognitivist underpinnings of Fodor's theory his view of modules as 'mental organs'faces an untenable dilemma that is to be traced back to the earliest history of modem cognitive science, viz. to the rationalist-computationalist research program initiated by Descartes and Male-branche. The tension characteristic for the Cartesian program was one that arose between information correlation and information processing accounts of the transactions between body and mind. Similarly, the tension characteristic for Fodor's theory of modularity is one between a causal account of modules on the model of simple detection mechanisms, and an information processing account of modules on the model of vast and elaborate cognitive systems. It is argued that the resulting concept of a cognitive module Fodorian style constitutes an amalgam of incompatible desiderata that fails to stake out a natural kind for cognitive science. As an alternative account, the final section shows connectionism to be capable of encompassing both Gibsonian and 'new look' accounts of cognitive achievements within one theoretical perspective, thus providing a fruitful interfield theory capable of combining the theoretical resources of the ecological approach with the indispensable theoretical complement provided by psychological processing accounts. This change of perspective would ultimately involve recasting the symbo-functionalist notion of cognitive function along bio-psychological lines. (shrink)