 The Principles of Sociology has often been considered seminal in the development of modern sociology both for its method and for much of its content. Replete with endless examples from the distant past, recent past and present, it speculatively describes and explains the entire arch of human social  evolution.[3]  Part V, “Political Institutions,” is especially relevant for understanding Spencer’s ethics. Together with his Principles of Ethics, “Political Institutions” crowns the synthetic philosophy. They are its whole  point.[4]