Luhmann’s methods derive from his theoretical problems, not methodological orthodoxy.

Evidence

Luhmann’s approach to empirical research bears little relation to the ethnographic studies, social surveys or observational reports that fill the pages of today’s sociology journals. Both Luhmann’s methods and the technical vocabulary he employs all flowed from the theoretical problems he set himself. While his eclectic research methods may not comply with the conventional, contemporary requirements for social science research, with its insistence on replication, testability and compliance with a recognized methodology, they are nevertheless empirical in that they rely on observations in the broadest sense of the term – both his observations and those derived from secondary sources. — Niklas Luhmann, Trust and Power, 29