Abstract
The paper concerns mutual relations between two metaphysical positions: “superessentialism,” claiming that all properties of every object are essential, i.e.necessary, and “necessitarianism,” claiming that everything is necessary, i.e. there is only one possible world. The theories of Spinoza and Lewis serve as examples. In section I the two positions are characterized. In section II and III interpretations of Spinoza’s and Lewis’s metaphysics are presented, and it is explained to what extent they can both be considered superessentialists and necessitarians. In section IV the two theories are compared. In section V three possible ways of arguing for superessentialism are presented. It is then shown that the premises of these arguments appear, at least implicitly, in both of the theories. In section VI additional premises are numbered which have to be further assumed to prove necessitarianism. In the final section it is shown how Lewis can claim that there are contingent facts, while being a superessentialist and a necessitarian. It is argued that his claim of contingency is a matter of semantics, not of metaphysics.