Intellectual history and the history of political thought are siblings, perhaps even twins. They have similar origins and use similar materials. They attract many of the same friends and make some of the same enemies. Yet like most siblings, they have different temperaments and ambitions. This essay explores the family resemblances and draws out the contrasts by examining two major works by one of the most prominent political theorists of the past half-century, Alan Ryan, who has recently published two big (...) books that intellectual historians will find rewarding and provocative. (shrink)