In the end, it is perhaps a question of whether common ground may be
discovered for human attitudes and judgment. In juridical terms, the
question is whether common legal principles can gain sufficient accep-
tance to unite the different systems within one meaningful structure.1
Two themes have been developed in this work: first, a centralising or uniting theme, in defence of construing and applying all international law, including the WTO treaty, in the context of other norms of international law, be they customary law or other treaties; second, a theme calling for the recognition of the diversity between states and the contractual freedom of states to change their minds and to decide for themselves to which treaty or norm they want to give preference. This second theme is not a centralising or uniting one, but a centrifugal one allowing for regional and state-to-state differences in legal relationships. The tension between these two themes explains why this thesis, though focusing on conflict and conflict resolution, devoted large parts also to the process of accumulation of norms.
The interplay of norms in international law is no longer of academic interest only. In today's interdependent world, where states must cooperate in pursuit of common objectives and do so under the auspices of an ever increasing number of distinct international organisations, the potential for conflict between norms is very real, indeed. In the absence of a centralised international law-maker, the multitude of law-makers and other actors, be they domestic or international, at work on the international scene fuel the risk of conflict of norms arising (chapter 1).
1 Max Sørenson, ‘Autonomous Legal Orders: Some Considerations Relating to a Systems Analysis of International Organisations in the World Legal Order’(1983) 32 ICLQ 559 at 576.