2. A Non-Reducible Hierarchy of The Sciences

Most scholars in theology and science, while accepting the importance of methodological reductionism in science, view epistemic reductionism and reductive materialism as undercutting the credibility of higher-level disciplines and supporting the ‘conflict’ model between science and theology. To counter this, they typically argue that the academic disciplines form a non-reducible hierarchy, starting from physics at the bottom and moving upwards through chemistry, biology, physiology, the neurosciences, the behavioral, psychological and social sciences.One should clearly note that this is not a valuative or axiological hierarchy, such as those supporting dominance or patriarchy, but a strictly epistemology hierarchy which allows the argument for non-reducibility... The ordering of the hierarchy reflects the increasing complexity of the phenomena being studied; more importantly, it allows both for rules of constraint and genuine emergence. Constraint implies that the laws, processes and properties at lower levels, such as physics and biology, constrain the laws, processes and properties at upper levels, such as psychology or ethics. Thus the laws of chemistry must be consistent with, and not contradict, the laws of physics. Emergence implies that upper levels are partially autonomous; they include new laws, processes and properties which cannot be fully reduced to, explained away by, or derived from those of the lower levels. The ordering of the sciences in the hierarchy corresponds roughly to the rise of ever more complex physical and biological systems during the history of the universe, including galactic, stellar and planetary development, and eventually molecular and evolutionary biology.

As early as 1979, Arthur Peacocke described such a hierarchy of disciplines, drawing on the writings of M. Beckner, M. Polanyi, and E. Nagel along with Ayala and T. Dobzhansky.Peacocke, Creation and the World of Science, IV/I, II, Appendix C.By 1993 he had foliated the hierarchy into two dimensions: vertically it consists in four levels of increasing complexity (the physical world, living organisms, the behavior of living organisms, and human culture) while horizontally it depicts systems ordered by part-to-whole hierarchies of structural and/or functional organization (eg., in biology: macromolecules, organelles, cells, organs, individual organisms, populations, ecosystems).Peacocke, Theology for a Scientific Age, Ch. 12, esp. p. 216, Fig. 3. See also Peacocke, God and the New Biology, Ch. 1, esp. p. 16, Fig. 2. An important, though unsettled, issue here involves the role...Peacocke’s analysis undoubtedly reflects the broad consensus of the scientific community.

A key issue, though, is the place and role of theology in the hierarchy of knowledge. Peacocke tends to place theology at the top of the hierarchy. As the all-inclusive study of God, humanity and the world it cannot be isolated from, but instead it should seek to integrate, all that we know from the rest of hierarchy. Moreover, by putting theology at the top, it will be maximally constrained by the rest of human knowledge. Moreover, by placing theology at the top of the hierarchy, it is maximally constrained by, and responsible to, the discoveries and conclusions of the other disciplines.Peacocke, Creation and the World of Science, Appendix C; Peacocke, Theology for a Scientific Age, Ch. 12, esp. parts 6-9.In a recent proposal, Nancey Murphy and George Ellis suggest that the hierarchy be modified into the shape of a ‘Y’. The hierarchy starts with physics and moves up to chemistry and biology. Here, though, the hierarchy splits, with one branch leading to levels which study more encompassing wholes, including geology, ecology, astrophysics and cosmology, while the other leads to levels which study more complex systems, including psychology, the social sciences, and ethics. An inverted ‘Y’ then rejoins lines from cosmology and ethics to end in theology.Murphy and Ellis, On the Moral Nature of the Universe, Ch. 4, esp. p. 65, Fig. 4.1, and Ch. 9, esp. p. 204, Fig. 9.3. See also Ch. 4, esp. p. 86, Fig. 4.10. A crucial ingredient of their argument is that the higher levels in the scheme complete the lower levels by offering answers to key questions raised by them. This gives theology an essential role in the overall system: “A single theory of divine purpose answers the ultimate questions arising from each branch of the hierarchy.”Op. cit., p. 204. For a recent set of critiques of their views, see Christoph Lameter, "Cosmology in On the Moral Nature of the Universe by Murphy and Ellis," CTNS Bulletin 19.4(Fall 1998); Richard...

Causal reductionists, however, might allow for a hierarchy of disciplines while still claiming that all causality is bottom-up. Even if higher level theories describe the regularities of their phenomena in apparently irreducible ways, the possibility of causal reductionism remains, as exemplified in the mechanistic philosophy of the 18th and 19th centuries.For a recent analysis of the role of causal reductionism in mechanism, see Murphy, Beyond liberalism and fundamentalism, Ch. 3.To counter this, a variety of scenarios have been explored in which processes at upper levels actually do influence processes at the lower levels. These include ‘top-down causality’, ‘whole-part constraint,’Arthur R. Peacocke, "God's Interaction with the World: The Implications of Deterministic "Chaos" and of Interconnected and Interdependent Reality," in Chaos and Complexity: Scientific...and ‘supervenience.’The mechanistic view of nature in the 18th and 19th centuries was a powerful example of such a claim. Murphy, for example, clearly shows how physical causality at the bottom level bequeathed Laplacian...(See Part 2, A, 2, Divine Action)

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3. Non-Foundational (Holist) Epistemology

Contributed by: Dr. Robert Russell