Abstract

In the history of ethics, St. Thomas Aquinas represents the zenith in the intellectualist tradition. The intellectualist tradition centers upon the idea that all precepts of morality are fundamentally rational. Moreover, these moral precepts have their source in the divine intellect. In time after Aquinas, the Franciscan voluntarists, most notably John Duns Scotus and William Ockham, argued that the divine will was the source of all morality. Thus, the first purpose of this dissertation is to understand Aquinas as the paradigmatic intellectualist of the high middle ages. ;This dissertation traces the origins of Aquinas' intellectualist perspective to Aristotle and St. Augustine and then shows how Aquinas develops their ideas in his own fashion. These two thinkers represent two strains of thought in Aquinas' ethic. Aristotle emphasizes the role reason, as a natural human power, plays in all morality, while Augustine and the Christian tradition lays an emphasis upon the divinely revealed truths of morality as found in scripture. The second purpose of this dissertation is to understand precisely how the naturally known principles of morality relate to the divinely revealed truths given from God as found in the decalogue. ;The key to understanding Aquinas' place in the history of ethics and how his natural and revealed ethical views are related is to focus on the issue of right reason, recta ratio. Right reason is a term Aquinas employs throughout his moral theory even in regarding those precepts that have been given by divine revelation. ;The precepts of the decalogue are rational insofar as they proceed from God. Even commands by God that apparently conflict with the precepts of the decalogue are rational. Thus, how God is able to command actions that apparently conflict with the decalogue provides the key to understanding the rational nature of all morality