Book excerpt: This challenging and provocative book argues against much contemporary orthodoxy in philosophy and the social sciences by showing why objectivity in the domain of ethics is really no different from the objectivity of scientific knowledge. Many philosophers and social scientists have challenged the idea that we act for objectively authoritative reasons. Jean Hampton takes up the challenge by undermining two central assumptions of this contemporary orthodoxy: that one can understand instrumental reasons without appeal to objective authority, and that the adoption of the scientific world view requires no such appeal. In the course of the book Jean Hampton examines moral realism, the general nature of reason and norms, internalism and externalism, instrumental reasoning, and the expected utility model of practical reasoning. The book is sure to prove to be a seminal work in the theory of rationality that will be read by a broad swathe of philosophers and social scientists.