International Society for Science & Religion - Library Project

Evolution and Emergence: Systems, Organisms, Persons

edited by Nancey Murphy , William R. Stoeger

Introductory Essay by Thomas Tracy

One of the hallmarks of modern science has been the effort to understand complex natural structures by analyzing their parts and exploring how the relations of these parts give rise to properties of the whole. This explanatory strategy has been enormously successful, and has generated a nested structure of scientific disciplines that describe ascending levels of organizational complexity in nature. These range from the underlying constituents of things explored by subatomic physics up through the molecular interactions studied by chemistry, the processes of organic life examined by biology (including the dynamic networks described by ecology and evolutionary biology), and the human sciences of psychology and sociology. Clearly, each of the higher levels in this hierarchy depends upon those that underlie it. Should we also conclude that the higher levels can in some sense be reduced to the lower? This collection of essays provides expert guidance on this question, sorting out the various meanings of “reduction,” developing the contrasting concept of emergence, and exploring the implications of these ideas for some important topics in theology.

The anthology is organized into three parts. In the first section, essays by Nancey Murphy, Robert Van Gulick, and Terrance Deacon address central philosophical questions about inter-level relationships and reductionism. These authors accept ontological reduction, by which they mean roughly that higher level entities are built up out of the basic physical ‘stuff’ of nature (whatever that happens to be) without the addition of new kinds of constituents. They combine this, however, with a rejection of causal and explanatory reduction, which asserts that the causal roles ascribed to higher level structures can be analyzed entirely into the causal operation of their parts. The result is “non-reductive physicalism,” that is, a position that affirms causal closure at the micro-physical level but denies that all causal efficacy flows from the bottom up. “Top-down” causation occurs when a system of relationships at a higher level constrains, or selectively activates, the causal powers of its parts.

The second section of the anthology, focusing on scientific questions, includes essays by George Ellis, Don Howard, Martinez Hewlett, Alwyn Scott, and Warren Brown. These authors explore the evidence of emergence at various levels in nature. Downward causation appears to be at work even in fundamental physics, as illustrated by the striking phenomenon of quantum entanglement. The biological sciences, especially in the study of evolutionary dynamics, give close attention to selection effects that reflect constraints imposed by systems (both within and among organisms) upon their parts. Further, as cognitive scientists seek to understand the causal roles of mental processes, one important model focuses on downward causation occurring through linked feed-back loops that provide higher level controls on behavior.

The third section addresses the implications of these ideas for theological issues, and includes essays by William Stoeger, John Haught, Arthur Peacocke, Niels Gregersen, and Philip Clayton. Concepts of emergence and downward causation have implications for theological anthropology, and they provide resources for modeling God’s relation to the world in creation, redemptive action, and eschatological consummation. Traditional views of God as primary (creative) cause can be enriched by recognizing that God’s action through secondary (created) causes includes both bottom-up and top-down processes. Panentheists can make use of these ideas to develop a view of God as encompassing the world in a system of all systems, and as acting top-down to constrain and integrate the activity of the parts of the God-world whole. The theological proposals in this volume richly illustrate the fruitfulness of the idea of emergence for the ongoing conversation between science and religion.