Das Aggregationsproblem bei Mikro-Makro-Erklärungen

The present paper discusses a component of the micro-macro explanatory model (i.e. the individualistic research program): the question is whether and, if so, how collective properties (or, equivalently, macro variables) can be constructed by properties of individuals (i.e. by aggregating micro variables). This is the aggregation problem. After sketching the procedure of micro-macro explanations and its possible problems the state of research in regard to the aggregation problem is described. Then two kinds of aggregation are analyzed in detail: analytical aggregations (i.e. the micro-to-macro relationship is a logical one) and empirical aggregations (i.e. the micro-to-macro relationship is empirical). It is further discussed whether there exist collective properties that cannot be reconstructed individualistically. Many collective properties emerge by the unintended consequences of individual action. It is argued that the structure of micro-macro explanations do not differ if these consequences are intended or unintended. In the final part it is claimed that there are emergent properties but that they do not invalidate methodological individualism. In this context it is argued that “ontological” arguments are not helpful for solving explanatory problems of the social sciences.