Thinkers such as Grotius, Hobbes, and Kant maintain that the shared laws of justice are not revealed by God to humans but can be accessed by reason through an understanding of human nature. This type of iusnaturalism integrates natural law and positive law as species of the same genus since they share one principle of common validity - political power. Moderate iusnaturalism is also another variant, which emphasizes how natural law exists together with positive law within a legal dualism that rejects all monisms as well as the so-called extreme iusnaturalism. The extreme type holds that "natural law exists and all that exists is natural law". It also recognizes that morality is one of the traits for characterizing what law is.