The Synderesis Rule and Right Reason

Abstract

In recent years attention has been redirected to the significance of the ethical rule that should be done and evil avoided. It may be called the synderesis rule (SR) or principle, since in its most influential presentation it was associated by Thomas Aquinas with the intellectual habit called syn deresis. In 1965 Germain Grisez published an article on this subject which at tracted much interest in America and England.1 He argued that the principle as found in Aquinas's treatise on laws in the Summa of Theology (bonum est faciendum etprosequendum, et malum vitandum2) has been misinterpreted in the common Scholastic tradition. In particular Grisez maintained that the common interpretation is wrong in restricting the good and evil, as used in this formula, to the moral order. Further, he suggested that the SR does not have the obligatory force of an imperative. While I cannot accept all of Grisez's reinterpretation of the SR, it is well to state immediately that his objection to the claim that all precepts of natural law are derivable from this first principle by a process of deductive reasoning is very well taken. My view is that the SR cannot of itself be the source of our knowledge of what is good or evil. Later we will see that it is a formal principle with no specific material content. Subsequently the Oxford legal philosopher, John Finnis, in a remarkable study of natural-law thinking, expanded Grisez's interpretation.3 Finnis is es pecially emphatic in his condemnation of the teaching of post-Renaissance scholasticism, that the first principles of moral reasoning, as the products of synderesis, are identical with the last six commands in the Decalogue.4 Like Grisez he stresses the point that all primary prin ciples are self-evident (per se nota) according to St. Thomas.5 Since Finnis combines some familiarity with the thinking of Aquinas with a background in British analytic philosophy, his contribution to the updating of the role of the SR is quite important. Both Grisez and Finnis tend, however, to unify the kind of thinking that Aquinas discussed under the virtue of prudentia (variously translated as prudence, wisdom, or reasonableness) with the sort of discourse that St. Thomas called philosophia mor?lis or ethica.6 As we will see later this unification of the work of prudence and of moral science under the name of practical reasonableness introduces a basic confusion of two different kinds of prac tical reasoning.