A house built on sand: A Thomist critique of Common Good Constitutionalism

Common Good Constitutionalism claims to develop an approach to legal interpretation built on Aquinas’ definition of law as ‘nought else than an ordinance of reason for the common good made by the authority who has care of his community and promulgated.’ This paper argues that Vermeule’s approach misinterprets this definition and is therefore of little value to contemporary natural law scholarship.

The paper will begin by laying out a summary account of Vermeule’s position; only by looking to the purpose of law can we correctly interpret and apply legal rules, and that the Thomist concept of the ‘common good’ can provide the background context we need to do this successfully. However, on his reading, the common good limits what is practically reasonable within Aquinas’ definition of law. I believe this portrayal of a one-directional relationship between the two concepts to be misplaced.

This claim will be justified in the following three sections. The first will argue that a holistic reading of Aquinas sees humans’ capacity for practical reason as dispositional, and that this requires us to see it as located prior to the common good in a Thomist account of agential deliberation. This requires us to accept that practical reason necessarily shapes our understanding of the limits of the common good, and that Vermeule’s position that the common good shapes limits the practically reasonable is, at best, a limited understanding of the relationship between the concepts. The second will seek to establish that Aquinas’ account of epikeia also requires us to accept a two-way relationship with regards to the application of legal rules to subjective legal rights, and the third will demonstrate the same conclusion is necessary when we translate Vermeule’s framework into Raz’s understanding of the nature of exclusionary reasons within legal reasoning.

Taken together, these arguments demonstrate that the ‘Common Good’ cannot constrain the practically reasonable as Vermeule’s approach suggests. As it is incompatible with both Thomist and Razian understandings of how legal reasons are internalised by legal actors, Common Good Constitutionalism cannot succeed in its aims and ought to be rejected.