Abstract

This article offers an exposition and critical discussion of the account of the truth of practical reason in the natural-law theory of Germain Grisez, Joseph Boyle, and John Finnis. The exposition rests mainly on an article published by these authors in 1987. There they argue that “true” is said of theoretical and practical knowledge in radically diverse senses. They also distinguish, within practical knowledge, between two kinds of truth, practical and moral. This distinction is tied to their understanding of relations that obtain among the first principles of practical reason. The essay’s critical discussion raises problems for the account in all three areas and favors the view that “true” means the same for all knowledge. National Catholic Bioethics Quarterly 15.2 : 303–329.