This essay analyses the positions which are related to the quantitative and qualitative research models in the social disciplines; it examines the universality and invariance of scientific laws; and it presents the inadequacy of the conceptions of logical positivism and of classical epistemology, as well as the new concepts and two of the models which arose there from. Then, based on this it evaluates the epistemic status of research findings from both models, the scientific status of the disciplines and their theories and the rationality of the agreements reached over research conclusions: the limitations of scientific laws show the plausibility of quantitative research, which can be associated with the epistemic values of truth, inter-subjectivity and susceptibility of replication, and its conclusions can be considered as genuine knowledge, though not those of qualitative research. But these philosophical notions leave open the controversy over the appropriate conceptions to explore the social phenomena.