forthcoming in: Nachtflug der Eule: 150 Stimmen zum Werk von Niklas Luhmann. Gedenkbuch zum 15. Todestag von Niklas Luhmann (8. Dezember 1927 Lüneburg - 6. November 1998 Oerlinghausen), Magdalena Tzaneva (Ed.). Berlin: LiDi Europe Verlagshaus, 2013.
One can discard Luhmann’s contributions as flawed (e.g., Padgett & Powell, 2012, pp. 55-58) or discuss the limitations of the theory from a sociological perspective (e.g., Giddens, 1984, at p. xxxvi f.; Leydesdorff, 2010), but in my opinion, important steps were made by Luhmann in sociological theorizing when compared with his predecessors such as Parsons and Habermas, but also when compared with more empirically oriented contemporaries such as Merton and Giddens. These new developments were made possible by an interdisciplinary orientation in which Luhmann absorbed into his sociology, on the one side, Maturana’s theory of autopoiesis (self-organization) and, on the other, Husserl’s philosophy, and then provided a sociological reconstruction that can eventually be operationalized (Leydesdorff, 1996 and 2012). In my opinion, these new steps in terms of sociological theorizing were made mainly in the 1970s and 1980s, whereas the emphasis shifted to a synthesis of this oeuvre in the 1990s (e.g., Luhmann, 1997) and to the more philosophical ambition of developing a general theory of observation (Baecker et al.,  1999; Gumbrecht, 2003 and 2006; Leydesdorff, 2006). >>
** apologies for cross-postings
Professor, University of Amsterdam
Visiting Professor, Birkbeck, University of London.