The scope of libertarian law is normally limited to the application of the non-aggression principle (NAP), nothing more and nothing less. However, judging when the NAP has been violated requires not only a conception of praxeological notions such as aggression, but also interpretive understanding of what synthetic events count as the relevant praxeological types. Interpretive understanding—or verstehen—can be extremely heterogeneous between agents. The particular verständnis taken by a judge has considerable moral and political implications. Since selecting a verständnis is pre-requisite (...) to applying the NAP, the NAP itself cannot tell us which one we ought morally to choose. Therefore the application of the NAP calls on moral and political considerations outside of the NAP itself. Since some of these are more consistent with an endorsement of the NAP than others, libertarianism is not a “thin” commitment to the NAP alone, but a “thick” commitment to the NAP and other supporting moral and political considerations. (shrink)