Finnis and Aquinas on the Good of Life

Abstract

In his Natural Law and Natural Rights, Fundamentals of Ethics, and other works, the Oxford professor of jurisprudence and moral theologian John Finnis has elaborated a theory of ethics and natural law that he presents as being based on the thought of St. Thomas Aquinas. (Finnis has been influenced in this project by the moral theologian Germain Grisez, and has worked in cooperation with Grisez and Joseph Boyle on these issues, but I will confine myself to a discussion of Finnis’s thought, while noting that my conclusions will have implications for the views of Grisez and Boyle as well.) His account of natural law incorporates a particular account of human life as a good for practical reasoning, from which he concludes — in disagreement with Aquinas — that capital punishment is immoral. This conclusion has gained wide acceptance among Catholics, partly because of the influence of Finnis and Grisez’s moral theories. I want to examine his understanding of the good of life, contrasting it with the actual views of St. Thomas, and argue that it is mistaken. I will then explain why I think his mistake is an important one that needs to be avoided.Finnis presents his account of natural law as being modelled on St. Thomas’s account of the first principles of natural law, which is given chiefly in the Summa Theologiae, la2ae q.94 a.2. It may be helpful to sketch St. Thomas’s understanding of practical as opposed to theoretical reason. Theoretical reason aims at knowledge of how things are, and its activity terminates in belief about how things are.