As Friedmann explained, the changing demands of international society produced a demand for additional types of international law. In order to know what types of international law and institutions will be required in the future, we must ask ourselves how the issues we see today as international concerns, and the issues that we have not yet identified as international concerns, will develop. We must next ask what requirement for cooperation-in terms of both rules and organizations-they will occasion. Of course, we cannot anticipate everything, but we should not ignore the issues that and be anticipated by extrapolation from what we know