Full Idea
There is an objection to dualism that it cannot explain how the physical and the nonphysical interact, but the answer is simple on a natural supervenience framework - they interact by virtue of psychophysical laws (…which are as eternal as physics).
Gist of Idea
Supervenience makes interaction laws possible
Source
David J.Chalmers (The Conscious Mind [1996], 2.4.6)
Book Reference
Chalmers,David J.: 'The Conscious Mind' [OUP 1997], p.170
A Reaction
There are different sorts of laws. What Chalmers is hoping for would be a mere regularity, like the connection of cancer to smoking, but the objection is that the discovery of causal mechanisms, to give truly explanatory laws, is simply impossible.