My work is about meaning and grammar, in relation to the human faculty for language. Words often describe relations. When and how do the relations a word implies matter to the grammatical structure it occupies, or to the thoughts we express in using it? I pursue this question through semantic and syntactic analysis of argument relations, explicit and putatively implicit, as well as through studies of their acquisition by infants, and online comprehension by adults. The idea that some such relations are implicit relates to a guiding interest in the division between semantics and pragmatics.