Study Questions on Ch. 1 of the Concept of Law

1) Must laws exist within legal systems?
2) Why does Hart think that the skeleton account of the law on pp. 4-5 is not enough to answer the question "What is law?"?
3) What is wrong with the gunman theory of law? Is Hart assuming that the obligation that is missing in such a theory is a moral obligation to obey the law? 
4) What is the puzzle Hart identifies concerning the existence of rules? What is wrong with simply treating rules as predictions about people's behavior?
5) How would you describe Hart's methodology for identifying the nature of law?