Aquinas's Two Doctrines of Natural Law

This paper examines the role which the concept of natural law has to play in the political thought of Aquinas, as this is to be found in the Summa Theologiae. It focuses particularly on Aquinas's understanding of the relationship which exists between natural and positive law. It argues that Aquinas's views are inconsistent and that the Summa actually contains two quite different positions regarding this subject. One of these is inherited from the Stoic natural law tradition and the other from Aristotle. The former considers natural law to be a critical standard by means of which positive law can be evaluated by individuals, whereas the latter does not. On the contrary, it maintains that according to Aquinas the principles of natural law require interpretation, and that this interpretation is to be provided, not by the conscience of the individual moral agent, but by positive law. Focus on either one or the other of these two documents leads to quite different interpretations of Aquinas's political thought as a whole. One such interpretation sees Aquinas as being a distant forerunner of the liberal political tradition. The other associates Aquinas much more closely with the notion of authority and hence with conservatism in politics. The article concludes by commenting on the relevance of these different interpretations of Aquinas for the contemporary debate between liberals and communitarians.