In Chapter 5, Mill deals with a criticism of utilitarianism, which is that it has no link with the concept of justice. In order to debunk this claim, he goes through the rather challenging process of trying to define what justice is and how it can be linked to utilitarianism. After going through a series of different examples of justice, he finally develops a theory that helps show the link between utilitarianism and justice. Mill argues that there are perfect and imperfect obligations. Imperfect obligations are defined by him as being things that no person has the right to insist on having from another, and perfect obligations are those things that everybody has the right to demand from another. Justice finds a clear link with Mill's concept of perfect obligation, as if a person's pesonal rights have been impinged, they have a moral basis for seeking redress. Note how Mill defines a right in this chapter:
When we call anything a person's right, we mean that he has a valid claim on society to protect him in the possession of it, either by the force of law, or by that of education and opinion.
Mill therefore argues for the coexistence of rights and utilitarian philosophy, which distinguishes him from other utilitarians, who would actually argue that any notion of "rights" is incompatible within a utilitarian framework. Mill therefore in this chapter upholds the concept of justice within his philosophy through defending the notion of human rights.