Horgan on non-reductive materialism

Terence Horgan was one of the developers of supervenience theory as a way of developing a nonreductive materialist theory. I read his writings as a graduate student in the late 1980s. But he now has doubts about materialism, and he thinks supervenience as an unexplained brute fact is unacceptable. He also explains the British Emergentist position, represented today by Roger Sperry, and explains why this tradition's positions are unacceptable to present-day physicalists. Students of C. S. Lewis will note that the British Emergentist tradition is referred to by Lewis as Emergent Evolution.

Here.