Now that we know what academic disciplines are and how they emerged and developed, it is time to introduce interdisciplinarity. One of the most widely used and adequate definitions of interdisciplinarity comes from the National Academy of Sciences (2005):

Other definitions include those of Klein and Newell (1997), who define interdisciplinarity as “a process of answering a question, solving a problem, or addressing a topic that is too broad or complex to be dealt with adequately by a single discipline or profession […] and draws on disciplinary perspectives and integrates their insights through construction of a more comprehensive perspective” (pp. 393-394). Interdisciplinarity has become a buzzword in scientific debates, and it has been identified by many research funding organizations in Europe and the United States as an important factor in future research. Although there is no single accepted definition of interdisciplinarity and the term is sometimes used interchangeably with multidisciplinarity and transdisciplinarity, it is important to distinguish and describe these three different manifestations of research.

The basic difference between these manifestations of research that spread beyond a discipline is the extent to which researchers aim for the integration or synthesis of (disciplinary) insights. Interdisciplinary research literally means research between disciplines, referring to the interaction of disciplines with each other. Indeed, the Social Science Research Council in New York, which first used the term ‘interdisciplinary’ around 1925, aimed to facilitate collaborations between the social scientific disciplines it did oversee (Klein, 1990). Such interaction may range from the mere communication and comparison of ideas, through the exchange of data, methods, and procedures, to the mutual integration of organizing concepts, theories, methodology, and epistemological principles. In multidisciplinary research, the subject under study is also approached from different angles, using different disciplinary perspectives. However, in that case neither the theoretical perspectives nor the findings of the various disciplines are integrated.