The aim of this paper is to reexamine what kind of insight the Sociology of Scientific Knowledge (SSK) provides us concerning our understanding of science. SSK has definitely described some crucial dimensions of science which traditional sociology and philosophy of science had not taken notice of. However, it seems that SSK doesn't offer any clear implication for our understanding of scientific rationality. I consider this equivocalness a significant problem to be solved, since some claims raised by SSK provide the background assumptions for much of recent research in Science Studies, like the Science, Technology and Society (STS). To make clear what implications are to be brought out from the claims of SSK about the social dimensions of science, I incorporate some recent arguments of Social Epistemology. Recent studies in Social Epistemology show interesting facts concerning the relationship between the social dimensions of science and scientific rationality. Focusing on Philip Kitcher's discussion about the division of cognitive labor and Miriam Solomon's "Social Empiricism, " I argue that the social dimensions of science sometimes make scientific decision-making rational, and sometimes they do not: it is entirely contingent how the social dimensions of science affect the results of scientific activities. In conclusion, I argue that we should not use the claims of SSK about the social dimensions of science as theoretical bases for our evaluation of science, but just as a tool for identifying various factors underlying decision-making processes. I suggest that this interpretation of the claims of SSK offers a better way to utilize our knowledge of social dimensions of science in Science Studies.