related. The classic case of this is Esping-Andersen's research on social welfare systems. He noticed there was a difference in types of social welfare systems, and compared them based on their level of decommodification of social welfare goods. He found that he was able to class welfare states into three types, based on their level of decommodification. He further theorized from this that decommodification was based on a combination of class coalitions and mobilization, and regime legacy. Here, Esping-Andersen is using comparative research: he takes many western countries and compares their level of decommodification, then develops a theory of the divergence based on his findings. Comparative research can take many forms. Two key factors are space and time. Spatially, cross-national comparisons are by far the most common, although comparisons within countries, contrasting different areas, cultures or governments also subsist and are very constructive, especially in a country like New Zealand, where policy often changes depending on which race it pertains to. Recurrent interregional studies include comparing similar or different countries or sets of countries, comparing one's own country to others or to the whole world. The historical comparative research involves comparing different time-frames. The two main choices within this model are comparing two stages in time (either snapshots or time-series), or just comparing the same thing over time, to see if a policy's effects differ over a stretch of time. When it comes to subject matter of comparative inquiries, many contend there is none unique to it. This may indeed be true, but a brief perusal of comparative endeavours reveals there are some topics more recurrent than others. Determining whether socioeconomic or political factors are more important in explaining government action is a familiar theme. In general, however, the only thing that is certain in comparative research issues is the existence of differences to be analysed. Development As Moutsios argues, cross-cultural and comparative research should be seen as part of the scientific spirit that arose in Greece in the 6th century and the overall appreciation of knowledge and learning that was characteristic of the 5th century. In other words, it is part of the emergence of episteme and philo-sophia, as a love for knowledge that is independent from material benefits. Episteme, as a form and activity in the field of logos, marked the break of cognitive closure and advanced empirical inquiry, logical argumentation and the search for truth. And the