necessitarianism the doctrine that necessity is an objective feature of the world. Natural language permits speakers to express modalities: a state of affairs can be actual (Paris’s being in France), merely possible (chlorophyll’s making things blue), or necessary (2 ! 2 % 4). Anti-necessitarians believe that these distinctions are not grounded in the nature of the world. Some of them claim that the distinctions are merely verbal. Others, e.g., Hume, believed that psychological facts, like our expectations of future events, explain the idea of necessity. Yet others contend that the modalities reflect epistemic considerations; necessity reflects the highest level of an inquirer’s commitment. Some necessitarians believe there are different modes of metaphysical necessity, e.g., causal and logical necessity. Certain proponents of idealism believe that each fact is necessarily connected with every other fact so that the ultimate goal of scientific inquiry is the discovery of a completely rigorous mathematical system of the world. See also DETER- MINISM , FREE WILL PROBLE. B.B.