= a reference to an unknown location; normally used with the purpose of finding out which location that is; sometimes used in rhetorical questions expressing one's conviction that such a location cannot be found
where?
Spatial Referents
= a reference to an unknown location, but focused on the question whether an object actually exists at all, rather than with a specific location in mind
where?
Circumstantial Referents
= a reference to an unknown location, but focused on the (often rhetorical) question whether an event may ever take place at all, rather than with a specific location in mind