They establish the procedures by which primary rules can be introduced, modified, or enforced. Continuing our football metaphor, an example of a secondary rule would be that a red card can be overturned after a retrospective review appeal. Hart asserts that only the most trustworthy and good-willed societies can survive with fair primary rules. In reality, our societies are not so idyllic and many problems will arise. Since there would be no systematic method of creating rules, there would be uncertainty as to their actual nature; the system would be very static, since any changes in the rules would have to happen organically; finally, without a defined method of adjudication, inefficiencies would arise from disputes over whether a rule was actually broken. These three problems can be solved by the introduction of three types of secondary rules, in order: recognition rules, change rules and