Value Incommensurability in Natural Law Ethics: A Clarification and Critique

The foundation of natural law ethics is a set of basic human goods, such as life and health, knowledge, work and play, appreciation of beauty, friendship, and religion. A disputed question among natural law theorists is whether the basic goods are "incommensurable." But there is widespread ambiguity in the natural law literature about what incommensurability means, which makes it unclear how this disagreement should be understood and resolved. First, I clear up this ambiguity by distinguishing between incommensurability and incomparability. I show that proponents of New Natural Law Theory hold that basic goods are both incommensurable and incomparable, whereas proponents of Classical Natural Law Theory hold that basic goods are incommensurable but comparable. Second, I critique the leading New Natural Law arguments for the incomparability of basic goods. Throughout the article, I explain why value incommensurability is an essential feature of natural law ethics but value incomparability is not.