TAXONOMY OF MODAL REALISMS

Modal realists should affirm some sort of correspondence theory of truth for modal language. A suitable sort of correspondence theory is furnished by the possible-worlds semantics found in Chapter 3 – provided that we can believe there really are the sorts of possible worlds and other possibilia which such semantics requires. We defended the view that possible worlds and other possibilia do exist and that possible-worlds semantics can be construed realistically, as a literally true account of what the things in the world are which make modal claims true.

In saying that possible worlds exist, however, we are so far saying very little about the nature of the truthmakers for modal claims. Very little has been said about what possible worlds are, what they are made of, how they are related to other things that exist, and so on. A modal realist must fill in such details about the nature of possible worlds before the formal semantics in Chapter 3 can provide an adequate explanation of the truthmakers for modalities.

Different realist theories will give different accounts of the nature of possible worlds. Yet it is convenient to express all such theories within a single framework. In all realist theories, something may be said to be possible just when there is a world which represents the actual world as being a certain way. Different possible worlds are different things, each of which represents the actual world as being a certain way.