The physicalism of today accepts four fundamental interactions: gravity, electromagnetism, and the strong and weak nuclear forces. It does not accept mental force. The ultimate, counter-intuitive and thus mostly unwanted implication of this is epiphenomenalism: that mentality is completely useless, like the steam from a locomotive engine.[9]
I mean, according to 'physicalism' wouldn't 'mental' force just be an instance of the other four forces? And how does he arrive at that spectacular conclusion, i.e. that 'mentality is useless', citing only some paper from 1874?