The term epistemology is used with two separate meanings according to different cultural traditions. In English-speaking countries, epistemology denotes the philosphical theory of knowledge in general: in this sense, it includes themes and problems such as the question of the possibility of valid knowledge, the analysis of the nature of such validity, the foundation of knowledge on reason or on experience and the senses, the analysis of different types of knowledge, and the limits of knowledge. In continental Europe, the above issues are considered part of the field of the more general discipline of gnoseology (gnoséologie in French, gnoseologia in Italian and Spanish) or theory of knowledge (Erkenntnistheorie in German), whereas the aim of epistemological inquiry is restricted to scientific knowledge.

In this second sense, with particular respect to social sciences (and sociology, in particular) the fundamental epistemological question becomes: "Is it possible to acquire any valid...