The Logic of Comparison

Abstract

The development of the comparative method is largely attributed to John Stuart Mill ([1882] 1973, Book 3: 388–406) who outlined the method of agreement, based on a comparison of different instances in which a phenomenon occurs. This method is to be distinguished from but is also complementary to the method of differences, e.g. the comparison of instances in which a phenomenon occurs with precisely similar instances, except the one sought-after, in which it does not occur, as well as the more complex method of concomitant variations. The latter goes beyond the observation of measuring either the presence or absence of operative variables by observing variations of the operative variables and correlating these to each other.¹ Although originally designed for the natural sciences, the outline of these methods is widely regarded as the rationale for the comparative method in social sciences (Kleinsteuber 2004: 65; Lijphart 1971: 688). The basic requirements for every comparison are, accordingly, degrees of similarities and differences. Both have to be taken into account. In the following I will briefly turn to some similarities and differences in legal traditions, politics and policies.