Abstract

There is a set of principles, the Principles of Possibility, that constrains whether a description picks out a genuinely possible world. To grasp the concept of metaphysical necessity is to have tacit knowledge of this set of Principles and to apply them in evaluating modal statements and thoughts. For a statement to be necessary is for it to hold in all descriptions that are not excluded as possible by the principles of possibility. This integrates the metaphysics and epistemology of necessity, without collapsing into mind‐dependence and without a commitment to modal realism. The treatment of the metaphysics validates the modal systems T and S4.