conceptual

This Friday, after a long chat with Christian Romero (and some participation of Andrés Villamil), I think I got convinced that there constant-variable distinction leaves room for a third semantic option. The context is the discussion on the nature of propositional terms, but the morals apply to any referential domain. In classic bivalent propositional logic, it is customary to distinguish between propositional constants that have a fixed truth value and propositional variables that can take either. This is just the application of a general distinction between constants that have a fixed value and variables whose reference can range over the whole domain of possible values. It just happens that because the domain in classical logic has only two possible values, there is no room for a third option. However, any even slighter larger domain immediately would suggest at least a third option: referential terms that have neither a fixed semantic value, nor can take any semantic value in ...