This paper aims at presenting the critique of both the quantitative and the qualitative research methodologies for social sciences in general and organizational sciences in particular. Quantitative and qualitative research models have been dominant over the second half of the twentieth century. Meanwhile, it has become a growing concern that a dichotomy between them should be overcome by combining them into a methodological pluralism. Positivism is the epistemological ground of quantitative methodology whereas phenomenology is the same with qualitative. It will be argued that for methodological pluralism, neither positivism nor phenomenology can suffice alone. This paper presents a comparison and analysis of both positivism and phenomenology with the intention of working out their fundamental presuppositions. The purpose of this investigation is to look for the possibility of outlining a theoretic paradigm for the practice of methodological pluralism.