(2) The second field is the elaboration of how we define and measure polarization within the capitalist world-economy. In the postwar period, polarization had become a relatively unpopular concept. World-systems analysis revived it, but has never really elaborated it. How do we prove its existence? Indeed, how do we measure its existence There is first of all the technical difficulty that no measurements are useful or relevant that are not world-system-wide, and that the boundaries of the system have been constantly changing over time. Secondly, polarization is not theoretically between states but between economic zones, and between classes and peoples. Finally, statistics have not been collected by state-machineries in a manner pertinent to such analysis. The problems of measuremernt are thus daunting.