"Autonomy has been defined in many ways. It has been treated as a synonym of freedom of the will, sovereignty, liberty and self-rule, or equated with self-knowledge, self-development, responsibility, dignity and integrity. It has been identified with self-assertion, critical reflection, freedom form obligation, absence of external causation and knowledge of one's own interests. The concept is related to actions, beleifs, reasons for acting, rules, the will of others, thoughts and principles. Gerald Dworkin's illuminating discussion of autonomy points out that the only consistent features in the variety of views and definitions of autonomy are that it is a desirable notion, that it relates to persons, and that the existence of a core meaning is doubtful. Many philosophers emphasise concepts such as freedom and self-definition when discussing autonomy. Thus, Dworkin suggests that autonomy enables people “to define their nature, give meaning and coherence to their lives and take responsibility for the kind of person they are”. John Rawls suggests that “acting autonomously is acting from principles that we would consent to as free and equal rational beings”."