 Projection from embeddings, especially negation, is standardly used as a diagnostic for presupposition (hence the term “negation test”). However it is important to try several types of embedding when testing for presupposition for a few different reasons. First of all, it is not always clear how to apply a given embedding diagnostic. For example, although it is widely agreed that the additive particle “too” is a presupposition-inducing expression, the negation test is awkward to apply because it is not immediately clear whether the negation outscopes the additive or vice versa in (6b), and it’s not obvious how the negation interacts with focus: