This paper reconsiders the possibility for unification of sociological theory by the rational choice model. This is induced by the claims of rational choice theorists that extending this model from economics to sociology can be conducive to establishing a unifying paradigm and method to be given ‘paradigmatic privilege’ within sociology. The outcome of such an extension of the economic approach has been ‘sociological rational choice theory’ or ‘rational action theory for sociology’. Within sociology, such a rational choice model is regarded as a major theoretical or/and methodological innovation and thus a ‘new’ promise for sociology's unification. Overall, the paper suggests that these ‘ecumenistic’ claims of rational choice theorists cannot be taken at face value since they are predicated upon dubious views of the relations between economy and society and between economics and sociology, including inadequate interpretations of neoclassical economics.