Questioning an epiphenomenalist syllogism

I focus on a certain epiphenomenalist syllogism summarized by Sarah Patterson. Contemporary epiphenomenalists believe that (A) mental properties are distinct from physical properties, (B) the physical properties of mental events are causally sufficient for the physical effects of those events, (C) given (B), no properties of mental events distinct from their physical properties are causally efficacious in bringing about their physical effects, and (D) the mental properties of mental events are therefore not causally efficacious in bringing about the physical effects of those events. I argue that (C) is at tension with the principle of nomological necessity supposedly binding supervening to subvenient properties, and I argue that (B), upon which (C) is based, is contradicted by the reality of intentionality, a reality that I demonstrate through, among other ways, a thought experiment about a counterfactual involving the possibility of changes in society at the removal of morality and law.