P L a N T I N G a ' S Doctrine of Essences

in terms of de dicto necessity, necessity conceived as a property of propositions or sentences. The heart of Plantinga's theory is his scheme for the reduction of de re modal sentences to equivalent de dicto ones. The idea is to provide an equivalent sentence containing no modal operators within the scope of a quantifier for every sentence asserting that some thing is necessarily or essentially thus and so. Central to the scheme are what Plantinga calls kernel propositions, defined by