Several scholars in Knowledge Organization (KO) and in Library and Information Science (LIS) have expressed concern that the field seems driven primarily by practical applications and professional practices. Yet others have stressed the need for research in the field to be more theoretically motivated, lest it continue to be perceived not as a scientific field but simply as a set of techniques used to solve problems. Hence, there have been calls for scholars and practitioners to make explicit the epistemological assumptions underlying methods used to design information services and tools for their users as this can help identify inherent biases. In answer to these calls, we undertook to examine the epistemological assumptions underlying research methods deployed in some fields of KO and LIS - namely information retrieval and topic mapping. A careful examination of these methods and their underlying assumptions showed that they exhibited epistemological hybridity, in this case, a combination of empiricism and positivism with a dash of pragmatism and hermeneutics at the end. We therefore hypothesize that it may not be a straightforward task for a researcher or an information professional to identify the epistemological assumptions underlying a particular piece of research or to claim that a method borrows solely from positivism, rationalism, empiricism or social-constructivism or historicism or hermeneutics, simply because there is a gap between epistemological theories and methods linked to them. A given piece of work may deploy methods linked to different epistemological theories. This is all the more true as the boundaries between epistemological theories can be difficult to discern, due to the fact that some of them overlap in their assumptions or are historically derived from one another. Although our examples are taken from the fields of LIS and KO, we suspect that our observations may be generalized to other scientific disciplines and fields of inquiry.