Possible worlds

Modality concerns what might or must be the case. Modal expressions are typically intensional. An expression α is intensional just in case the substitution of extensionally equivalent expressions under the scope of a need not preserve truth. Modal realism is the view that modal propositions are grounded in the existence of concrete, non-actual individuals and worlds. The fact that possibilities cannot be worlds has important implications. Indexical expressions are those that are context-sensitive. This includes expressions such as ‘I’, ‘you’, ‘here’, and ‘now’. The role that worlds traditionally played as maximal consistent doxastic states has been assumed by individuals in order to capture the distinctively de se. For every set of worlds there corresponds the set of individuals each of which inhabits one of those worlds.