Keenan (1987) observed that trivial determiners built from basic existential determiners (e.g.,either zero or else more than zero) are allowed inthere-insertion contexts, and that trivial determiners built from basic non-existential determiners (e.g.,either all or else not all) are not. This result is unexpected under the analyses ofthere-sentences proposed in Barwise and Cooper (1981), Higginbotham (1987), and Keenan (1987). I argue that the class of NPs barred from the postverbal position ofthere-sentences (strong NPs) is correctly characterized in presuppositional terms, as suggested (...) in de Jong and Verkuyl (1985) and Lumsden (1988). According to this characterization, strong NPs share one of the defining components of definiteness proposed in Heim (1982), namely the Descriptive Content Condition (DCC). How to derive the prohibition against strong NPs inthere-insertion contexts (definiteness effect) from the fact that strong NPs meet the DCC is not obvious, however. I argue that accounting for this prohibition involves regarding the XP-coda in [there be NP XP] as providing the contextual domain for the interpretation of the postverbal NP. (shrink)