Give reason why do we need …

We need some constraints or else society would descend into chaos. 

(i)Differences may exist between people regarding their ideas and opinions, they may have conflicting ambitions, they may compete to control scarce resources. 

(ii)There are numerous reasons why disagreements may develop in a society which may express themselves through open conflict. 

(iii)We see people around us ready to fight for all kinds of reasons ranging from the serious to the trivial. Rage while driving on the roads, fighting over parking spaces, quarrels over housing or land, disagreements regarding whether a particular film should be screened, all these, and many other issues, can lead to conflict and violence, perhaps even loss of life. 

Therefore every society needs some mechanisms to control violence and settle disputes.