How (not) to argue for the Relation between Natural Sciences and Law

Abstract

The thesis of an innate Universal Moral Grammar ('UMG') relies upon an analogy to the thesis of a universal grammar of the human faculty of language in linguistics. Drawing upon this faculty, John Mikhail, among others, argues that we humans have an inborn moral grammar. In this article this fascinating thesis is juxtaposed with critical perspectives and criticism from the various fields on which it is based. While there might be room for further research within the relevant fields in the natural sciences, the insecurities thus revealed forbid the use of UMG for law, something Mikhail actually suggested doing. Thus, the core argument of this article is that the relevance of UMG for law as claimed by Mikhail, for instance, to advise judges when identifying customary international (criminal) law or general principles of law, has to be rejected. To strengthen this argument I briefly elaborate on the is/ought debate and then engage in a thought experiment on Richard Dawkins' 'selfish gene' in order to address the relationship between natural sciences and law in more general terms as well.