This chapter focuses on Burke's Philosophical Enquiry into the Origin of our Ideas of the Sublime and Beautiful. Philosophical Enquiry takes up the thread of preoccupations that absorbed him throughout his twenties. It begins with an exploration of the classical theory of mixed emotions, focusing on Aristotle's signature categories of pity and terror. It proceeds to elucidate the affective psychology of manners, probing the feeling of exhilaration unleashed by pride and the instinct for subordination based on fear. Challenging the deist assumptions of a number of predecessors, Burke argues for the dependence of moral taste on duty. In the process, he articulates the reliance of ethics on religion, and traces the origins and development of superstition. The work also recapitulates Burke's antipathy to stoicism, along with his response to the leading moralists of the age, above all the writings of Hutcheson, Mandeville, and Berkeley, as well as Dubos, Condillac, Hume, and Smith. Although the Enquiry is not a comprehensive treatise in moral philosophy, it provides access to Burke's theory of human nature as it sets about accounting for uniform features of the mind.