Full Idea
To deal with the truth conditions for some adverbs, Davidson introduced a domain of 'events', and made adverbs into adjectival predicates of events.
Gist of Idea
We need 'events' to explain adverbs, which are adjectival predicates of events
Source
report of Donald Davidson (The Logical Form of Action Sentences [1967]) by William Lycan - Philosophy of Language Ch.9
Book Reference
Lycan,William G.: 'Philosophy of Language' [Routledge 2000], p.144
A Reaction
This seems to be a striking case of a procedure of which I heartily disapprove - deriving you ontology from your semantics. Do all languages have adverbs?