Where Humeans rule out the possibility of material or non-logical necessity, and thus of any associated knowledge a priori, the German legal philosopher Adolf Reinach defends the existence of a wide class of material necessities falling within the domain of what can be known a priori, for example in fields such as color and shape, rational psychology, law and economics. Categories such as promise or claim or obligation are, in Reinach’s view, exist as nodes in a system of necessary relations, (...) so that anyone who has experience of relevant instances of these categories is implicitly aware also of a corresponding family of relations to certain other categories – as for example that every promise implies a mutually correlated claim and obligation. Midway between the two extremes of Hume and Reinach stands Searle, who accepts necessary relations of the mentioned sorts, but sees them as human creations, following from ‘constitutive rules’ analogous to the rules of chess. We seek to demonstrate that Searle does not occupy a stable and acceptable half-way house between Hume and Reinach; that he, too, if he is to do justice to the very constitutive rules which form the center of his approach, must on pain of circularity embrace something like the Reinachian position. (shrink)