Publication Date

Spring 4-25-2011


School of Religion


Philosophy and Religion: Philosophy

Primary Subject Area



natural law, naturalistic fallacy, Thomas Aquinas


Ethics and Political Philosophy


Does Thomistic Natural Law theory commit the naturalistic fallacy? Ralph McInerny seems to think that Thomistic Natural Law, as Thomas Aquinas himself articulates it, escapes any potentially defeating criticism derived from the Naturalistic fallacy as described most notably by G. E. Moore and David Hume, which states that morality is not derivable from any natural property. The naturalistic fallacy, if successful in its purpose, deals a fatal blow to the school of moral philosophy that strives to adhere to traditional Thomism. In response to the criticism rooted in the Naturalistic fallacy, scholars like John Finnis insist that Thomistic Natural Law must, at the very least, undergo a re-articulation to answer this challenge. Their theory, new Natural Law Theory, subtly, but significantly departs from Thomism by replacing the telos with a deontological ethic. Thomistic Natural Law, traditionally understood, has much to offer contemporary philosophy in its own right—independent of newer, similar theories, and does not need any major revision to answer the challenge posed by either version of the naturalistic fallacy.