Full Idea
The explanation of my zombie twin's claims does not depend on consciousness, as there is none in his world. It follows that the explanation of my claims is also independent of the existence of consciousness.
Gist of Idea
If I can have a zombie twin, my own behaviour doesn't need consciousness
Source
David J.Chalmers (The Conscious Mind [1996], 2.5.2)
Book Reference
Chalmers,David J.: 'The Conscious Mind' [OUP 1997], p.180
A Reaction
Epiphenomenalism says my accounts of my consciousness are NOT because of my consciousness (which seems daft). Chalmers here gives a very good reason why we should not be a friend of philosophical zombies.