form of tradition, but were exaggerated, distorted, or biased toward a particular interpretation. Invented traditions are a central component of modern national cultures, providing a commonality of experience and promoting the unified national identity espoused by nationalism. Common examples include public holidays (particularly those unique to a particular nation), the singing of national anthems, and traditional national cuisine (see national dish). Expatriate and immigrant communities may continue to practice the national traditions of their home nation. In scholarly discourse In science, tradition is often used in the literature in order to define the relationship of an author's thoughts to that of his or her field. In 1948, philosopher of science Karl Popper suggested that there should be a "rational theory of tradition" applied to science which was fundamentally sociological. For Popper, each scientist who embarks on a certain research trend inherits the tradition of the scientists before them as he or she inherits their studies and any conclusions that superseded it. Unlike myth, which is a means of explaining the natural world through means other than logical criticism, scientific tradition was inherited from Socrates, who proposed critical discussion, according to Popper. For Thomas Kuhn, who presented his thoughts in a paper presented in 1977, a sense of such a critical inheritance of tradition is, historically, what sets apart the best scientists who change their fields is an embracement of tradition. Traditions are a subject of study in several academic fields in social sciences—chiefly anthropology, archaeology, and biology—with somewhat different meanings in different fields. It is also used in varying contexts in other fields, such as history, psychology and sociology. Social scientists and others have worked to refine the commonsense concept of tradition to make it into a useful concept for scholarly analysis. In the 1970s and 1980s, Edward Shils explored the concept in detail. Since then, a wide variety of social scientists have criticized traditional ideas about tradition; meanwhile, "tradition" has come into usage in biology as applied to nonhuman animals. Tradition as a concept variously defined in different disciplines should not be confused with various traditions (perspectives, approaches) in those disciplines. Anthropology Tradition is one of the key concepts in anthropology; it can be said that anthropology is the study of "tradition in traditional societies". There is however no "theory of tradition", as for most anthropologists the need to discuss what tradition is seems unnecessary, as defining tradition is