A striking characteristic of modern knowledge society is the rapid spread of certain ideas and concepts back and forth from everyday to scientific discourses, and across many different contexts of meaning. This work attempts to open up a new road to the study of these "dynamics of knowledge". Sociologists of knowledge and recently evolutionary theorists have offered explanations that either attribute social attention to particular ideas or shifts of meaning to the predominance of certain groups. Maasen and Weingart, however, offer a radical new explanation that explores knowledge dynamics by reference to the interaction between metaphors and discourses.