The Data of Ethics: bound with Justice

'Spencer regarded the Principles of Ethics - of which The Data of Ethics and Justice constitutes parts one and four respectively - as the culmination and crowning achievement of the System of Synthetic Philosophy, to which the other volumes on biology, psychology, and sociology had been mere preliminaries' - Michael Taylor, from the Introduction. In Justice Spencer revisits the Law of Equal Freedom which first appeared in Social Statics and forms the keystone of social morality.