In this paper we attempt to clarify the nature of the relation between the possessor and a possessed concrete noun in an English genitive. It is argued that such a relation cannot be thematic, regardless of whether the head or the genitive marker is considered to be the theta role assigner. A view is outlined of both possession and modification which allows the possessor to be interpreted as a pure modifier. In addition,
other cases of genitives are considered where the possessive item is either obligatorily (if present) or optionally coindexed with a Lexical Conceptual Structure (LCS) variable. The domain of the notion adjunct argument is modified to allow for the various relations a genitive may have to a head noun. This work supports a view of the Case Filter which considers case to be required by NPs rather than by arguments,
and it is supported by the behaviour of post-nominal genitives
