Full Idea
Epiphenomenalism is usually considered to be a form of dualism, but if we define it as the doctrine that conscious events are effects but not causes, it appears to be consistent with physicalism.
Gist of Idea
If epiphenomenalism just says mental events are effects but not causes, it is consistent with physicalism
Source
John Perry (Knowledge, Possibility and Consciousness [2001], §4.2)
Book Reference
Perry,John: 'Knowledge, Possibility and Consciousness' [MIT 2001], p.78
A Reaction
Interesting. The theory was invented to put mind outside physics, and make the closure of physics possible. However, being capable of causing things seems to be a necessary condition for physical objects. An effect in one domain is a cause in another.