How general can theories of 'why' and 'because' be?

This paper explores a taxonomy of uses of 'because' from the linguistics literature. It traces the apparent semantic differences between content, epistemic, and act 'because' to differences in attachment height. But it argues that the fact that these uses of 'because' never occur in the same environments is evidence of an underlying semantic unity. Arguments from such a distribution to underlying unity are familiar from phonology and morphology, and they are implicit in Quine's comments on ambiguity in Word and Object, but they have too rarely been deployed in semantics. Here, such an argument points the way towards an underexplored conception of polysemy, while also making progress on the rather more limited topic of the lexical semantics of 'because'. [ABSTRACT FROM AUTHOR]