This paper provides a theoretical examination of the inquiry of the Italian philosopher Enzo Paci (1911-1976) into the foundations of political economy. The article opens with an illustration of the issue of scientific knowledge in Edmund Husserl's phenomenology to which Paci refers. After clarifying the specific sense in which Paci conceives the task of science's foundation, this discussion illustrates his thesis, which links political economy to the experience of need. Two interpretations of Paci's thesis, both plausible, are then critically discussed. Paci's interpretation of Marx's critique of political economy is subsequently examined and his reading of Keynes's "General Theory" is discussed. Although Paci's inquiry is interesting because it delivers the epistemological reflection about economics from a purely methodological and formalistic perspective, it fails in its purpose. In conclusion the reasons for this failure are analysed; how an inquiry into the foundations of political economy ought to be stated in order to have a philosophical and epistemological relevance and in order to be significant in elaborating economic theory is pointed out.