The significance of emergence

This paper is an attempt to understand the content of, and motivation for, a popular form of physicalism, which I call ‘non-reductive physicalism’. Non-reductive physicalism claims although the mind is physical (in some sense), mental properties are nonetheless not identical to (or reducible to) physical properties. This suggests that mental properties are, in earlier terminology, ‘emergent properties’ of physical entities. Yet many non-reductive physicalists have denied this. In what follows, I examine their denial, and I argue that on a plausible understanding of what ‘emergent’ means, the denial is indefensible: non-reductive physicalism is committed to mental properties being emergent properties. It follows that the problems for emergentism—especially the problems of mental causation—are also problems for non-reductive physicalism, and they are problems for the same reason. The structure of the paper is as follows. In section 1, I outline what I take to be essential to non-reductive physicalism. In the second section I attempt to clarify what is meant by ‘emergent’, and I argue that the notion of emergence is best understood in terms of the idea of emergent properties having causal powers which are independent of the causal powers of the objects from which they emerge. This idea—’downward causation’—is examined in section 3. In the final section I draw the lessons of this discussion for the contemporary debate on the mind-body problem.