Supplemental Update (draft)∗

Starting with a well-known account due to Potts, supplements have been characterized as inert with respect to other content. But under closer scrutiny, the data shows that supplements can take scope and partici-pate in anaphoric links. As a corollary, the motivation for a semantics of supplements that places their content on a separate meaning dimen-sion is undermined. I argue that the core empirical facts pertaining to supplements, including projection, can be accounted for by more general, independently motivated factors such as anaphora resolution in discourse and the preference for surface scope in comparison to inverse scope. The account is formalized in a dynamic, compositional semantics that allows anaphoric links to and from supplement content. Since supplements are modeled as a kind of quantifier phrase modifier, scope interactions with semantic operators are allowed without further stipulation. When it takes widest scope, a supplement constitutes a separate proposal, thereby enabling both supplement projection and (non)deniability. The formal machinery uses only a single meaning dimension and requires no additional rules or representation layers with the exception of the dynamic meaning of the comma intonation that demarcates supplements from other content.