Journal of European Baptist Studies, Volume 9, Number 2, January 2009

parts. Developing a Concept of Downward Causation Throughout the remainder of this lecture I shall be relying heavily on work I have done with my colleague, neuropsychologist Warren Brown, in our book Did My Neurons Make Me Do It?: Philosophical and Neurobiological Perspectives on Moral Responsibility and Free Will. 5 The most cogent arguments against causal reductionism are those showing that, in many complex systems, the whole has reciprocal effects on its constituents. Donald Campbell and Roger Sperry both used the term ‘downward causation’ in the 1970s. Sperry often spoke of the properties of the higher-level entity or system overpowering the causal forces of the component entities. 6 Campbell’s work has turned out to be more helpful. 5 Murphy and Brown, Did My Neurons. 6 Roger W. Sperry, Science and Moral Priority: Merging Mind, Brain, and Human Values (New York: Columbia University Press, 1983), p. 117. How to Keep the ‘Non’ in Nonreductive Physicalism 9 Here there is no talk of overpowering lower-level causal processes, but instead a thoroughly non-mysterious account of a larger system of causal factors having a selective effect on lower-level entities and processes. Campbell’s example is the role of natural selection in producing the 1 remarkably efficient jaw structures of ants and worker termites. Downward causation is often invoked in current literature in psychology and related fields, yet it received little attention in philosophy after Campbell’s essay in 1974. However, in 1995 Robert Van Gulick spelled out in more detail an account based on selection. The reductionist’s claim is that the causal roles associated with higher-level scientific classifications are entirely derivative from the causal roles of the underlying physical constituents. Van Gulick concedes that the events and objects picked out by the special sciences are composites of physical constituents. However, he argues that the causal powers of such an object are not determined solely by the physical properties of its constituents and the laws of physics. They are also determined by the organisation of those constituents within the composite. And it is just such patterns of organisation that are picked out by the predicates of the higher-level sciences. These patterns have downward causal efficacy in that they can affect which causal powers of their constituents are activated. ‘A given physical constituent may have many causal powers, but only some subsets of them will be active in a given situation. The larger context (i.e. the pattern) of which it is a part may affect which of its causal powers get activated. . . . Thus the whole is not any simple function of its parts, since the whole at least partially determines what contributions are made by its parts.’ 7 8 Such patterns or entities are stable features of the world, often in spite of variations or exchanges in their underlying physical constituents.