ABSTRACTTheories on international law have been formed in compliancewith international landscape. In this regard, the former predominantnaturalist theory on international law which excludes the consent of astate in defining international law was replaced by the positivist theorywhich defines international law as the reflection of state consent in thenineteenth century. This positivist theory served international law in thetime of rapid progress of international law well until the mid-twentiethcentury. On the other hand, this current predominant positivist theoryon international law has been challenged by many problems because ofthe dramatic and unprecedented developments in international law sinceSecond World War.