Givenness, Contrastiveness, Definiteness, Subjects, Topics, and Point of View

A noun in its sentence plays many roles, or has the potential of doing so. For example, according to one traditional way of sorting out some of these roles the noun Betty in the sentence Betty peeled the onions might be said to function simultaneously as the grammatical (or superficial) subject, as the logical subject, and as the psychological subject (e.g., Hornby 1972). A typical way of demonstrating the independence of these three roles is to point out that in The onions were peeled by Betty, although Betty remains the logical subject, the other two roles are taken by the onions. In The onions, Betty peeled, furthermore, it may be said that the onions is the psychological subject, whereas Betty is the logical and grammatical one.