What is the main theme of Stammler’s theory of natural law?

The main theme of Stammler’s theory of natural law is to provide a standard for determining the justice of a given law. According to him ‘’all positive law is an attempt at just law’’. He says, the purpose of law is not to protect the will of one but to unify the purpose of all. The law of nature means to him a just law and a first law is that which harmonises the purpose within the framework of social life.