Abstract:

Serious actualism is the principle that, for every entity x and every property φ, it could not have been that x did not exist but had φ. The principle was called ‘serious actualism’ by A. Plantinga, who argued for it. Accepting it has serious consequences about how it is philosophically preferable to develop first-order modal logic. In the paper I show why some alleged counterexamples to the principle should not convince us, and then I offer three arguments for serious actualism and for the corresponding principle about relations. According to the first, by accepting those doctrines we avoid a serious difficulty when we try to explain when two properties, or two relations, coincide in extension. The second argument relies on some tenets about sets. The third improves upon Plantinga’s reasoning in favour of serious actualism. I then draw some conclusions about when a linguistic expression ought to be regarded as a predicate from a logical and semantic point of view. Finally, I discuss certain principles about time and space that are analogous to serious actualism.