Full Idea
If causation concerns events, then we have an identity theory of mental and physical events (particulars) [Davidson]. If causation is by properties, then it is mental and physical properties which are identical [Lewis and Armstrong].
Gist of Idea
Identity theory is either of particular events, or of properties, depending on your theory of causation
Source
Tim Crane (Elements of Mind [2001], 2.14)
Book Reference
Crane,Tim: 'Elements of Mind' [OUP 2001], p.52
A Reaction
Events are tokens, and properties are types. Tricky. Events are dynamic, but properties can be static.