  The content of some atomic sentences seems to hark exclusively from a particular region of discourse. For instance, ‘lactose is a sugar’ concerns chemical reality, while ‘\(7 + 5 = 12\)’ is solely about the realm of numbers (and operations on these). Not all discourse is pure or exclusive, however; we often engage in so-called ‘mixed discourse’, in which contents from different regions of discourse are combined. For example, consider: