The Background/Presupposition Rule (BPR) Whenever P is backgrounded, the presupposition is triggered that P* holds, where P* is the existential instantiation of P.
We will show that the BPR accounts for a whole range of focusing phenomena that either have been played down in the literature or have been explained with the help of ad hoc principles. The phenomena that we will discuss include domain restriction, negation, counterfactuals, and the presuppositions associated with 'only'.