Contemporary theorists of international politics do not see the world in the same ways nor do they agree on what is important to know, or how to know it. Disagreements are partly due to the increasing complexity of the world, but also derive from the development of many different viewing points. Some are geographic and cultural (Americans often view the world differently than, say, Japanese), but other perspectives come from different epistemological starting points and from different assumptions as to what constitutes reliable or useful knowledge, and how to create it. Debates in the 1960s revolved around problems of methodology. Today, we see in addition arguments over metaphysics, the purposes of theoretical activity (understanding versus praxis, for example), and a whole host of other divisive questions.