  If we take the family as a model here, we can see that children acquire obligations to obey their parents and to love and support their parents and siblings without having voluntarily entered into the relationships. And there may be some relation of authority between parents and children at least till the latter reach the age of maturity. Another model Dworkin invokes is that of friendship. He argues that though friendship does have an important voluntary component, it is not the case that people voluntarily agree to the terms of a friendship. They find themselves acquiring obligations of friendship as the friendship grows. Of course there is little in the way of authority in friendship and even in the family there is little authority once the children reach maturity.