What the law is and what it should be are entirely different. Hence a society can also make a law that might be immoral, and a wicked organization can also institute a system of laws.
Second thing that legal positivists believed was that the legal concepts are an important endeavor. Thirdly, they said that the laws are orders given by rulers that are followed by people forcefully. Hart was agreed on the first two points but he was not convinced with the third. He did not believe that a legal system is in total control of sovereign to command. According to him it was because of pressurizing of government that people do not obey laws.
In the Concept of Law, Hart has argued that compliance of law is impossible when imposed forcefully on public. Hart took a legal system as a union of primary and secondary rules and not as a compilation of individual laws.
He has defined primary rules as the rules which imply a force on a citizen on his deeds, that is, what he can and can not do. He said that secondary rules define specifics of the primary rules. ...