Holism is any attitude toward explanation that places emphasis on the importance of a whole system as against that of its individual parts. Holism is thus an epistemological term, reflecting a particular approach to explanation. The term was first used in English by South African statesman and author Jan Christiaan Smuts in 1926. Its roots within Western philosophy, however, go back to the German thinker George Wilhelm Friedrich Hegel (1770–1831), with his insistence that "the truth is the whole."

The concept of holism is important to three areas of the science-religion debate: (1) in the philosophy of science, where it is in particular tension with falsificationism; (2) in considerations of causation, including divine action, where holism is in tension with reductionism; and (3) in ecological thinking, where it is in tension with dualism and anthropocentrism.

Holism in the philosophy of science rests on an insight initially developed by Pierre Duhem (1861–1916), and refined by W. V. O. Quine (1908–2000), to the effect that scientific theories face the bar of experience as a whole, as a complex web of interrelated postulates and hypotheses. When an experimental result conflicts with current theory, proponents of the theory have a wide choice as to which elements to re-evaluate, not only altering the hypothesis being tested, but rejecting the result as an artifact, rejecting the apparatus as inappropriate, questioning the mathematical framework used to draw inferences from the result, or altering other hypotheses to fit the data. This runs counter to Karl Popper's proposal that science unfolds by a process of empirical falsification of discrete hypotheses.

Holism in the debate about causation

In discussions of holism and causation it is necessary to mention an important result in quantum theory, as well as a wider debate as to whether systems in any way cause the behaviour of their parts.

Quantum holism.

It is a remarkable feature of the mathematical framework of quantum mechanics that all the elements of an interacting system must be considered together. The wave function of all the components of a quantum system is collapsed by contact with an act of measurement, which gives rise to a definite behavior in all the particles concerned, be they electrons, photons, or some other particle. Thus, measurement of an electron's spin could simultaneously determine the spin of another electron with which it had once been paired, even if the second particle were on the other side of the universe. However, the EPR Paradox proposed by Albert Einstein and colleagues in the 1930s challenged this view. The experimental vindication of the predicted quantum result by physicist Alain Aspect in 1982 confirmed that reality must be viewed as more interconnected than classical science would have supposed. The Aspect result has given rise to highly speculative proposals, including explanations for telepathy. The precise implications of nonlocal interactions between quantum particles remain unclear.

Whole-part causation.

Can the behavior of individual elements of a system be influenced by the character of the larger system of which they are a part? That the answer to this is "yes" can be demonstrated in quite simple chemical systems, such as the Bénard cell, where coordinated geometric structures form when a liquid is heated in a certain way. A commonsense view of conscious agency might suggest that this sort of causation is also present when a person decides to move his arm. Donald T. Campbell and Roger W. Sperry developed the concept of top-down causation to describe instances in which larger wholes constrain the behavior of their components. This remains a contentious area of debate, especially in the study of the mind-brain relationship, where it focuses on the question as to what is doing the causing, other than the component neurons of the brain.

However, few thinkers would not concede that complex entities such as the cell, the multicellular organism, and the ecosystem, do have to be described in terms of emergent properties, types of explanation not necessary for lower levels of complexity. For example, molecules such as hormones are sent round the human body as "messengers," reflecting the state of the body as a whole. These messages change the state of molecules within the cells they reach. Moreover, the science of chaos emphasises that the behavior of many important types of systems, from the weather to the human heart, is exquisitely sensitive to the boundary conditions of the system. These considerations limit the effectiveness of scientific reductions, efforts to describe complex phenomena in terms of their component parts. The attempt to effect such reductions is essential to scientific methodology, but the experience of science is that explanations in terms of the functioning of larger wholes remain indispensable.

Two words of caution are in order in developing holistic accounts of causation. First, the previous paragraph simply states that description in terms of wholes influencing parts is a necessary explanatory device within scientific epistemology. It does not, however, establish an ontology of efficient causes of the sort to which the physics of forces lays claim. Second, sensitivity to initial conditions shows how important the overall environment is to chaotic systems; even a tropical rainforest is a whole within larger wholes.

John Polkinghorne and Arthur Peacocke have taken a lead in proposing that top-down causation can function as an analogy for the activity of God within the created order. Polkinghorne has focused on the mathematics of chaos as indicative of the flexibility and openness of creation to the input of divine information. In response to criticism that the equations of chaos are fundamentally deterministic, he speculates whether they may only be approximations to a more holistic account of reality. Peacocke's emphasis is, rather, on (1) the hierarchy of emergent properties of the universe and (2) that assertion that interaction between God and human minds is the highest known level of that hierarchy. Peacocke's terminology for the sort of physical causation to which divine action might be analogous has shifted from whole-part causation, to whole-part constraint, and finally to whole-part influence.

The words of caution above show the difficulties of the analogy. There is no model for how wholes can be causally effective, other than through the causal interactions of their components, and there are no wholes in the cosmos that are not themselves wholes-within-environments. Models of divine agency that stress whole-part causation do no more than indicate that two analogies may be somewhat helpful: the analogy of human mind-in-body conscious agency, and the analogy of God as the environment of the world.

Holism in ecological thinking

Discussions of holism in ecology draw on American naturalist Aldo Leopold's Sand County Almanac (1949), in which he emphasizes the importance of the overall health of the biotic community. These discussions also draw on the insistence of Norwegian philosopher and ecologist Arne Naess as to the need for a "deep-ecological" attention to the whole network of relationships in an ecosystem. These emphases marked an ethical shift away from a focus on the interests of humans (anthropocentrism), and towards a sense that humans are no more than one part of the natural world. This sense is thus in tension with any dualistic view of humans that values only the status of their souls.

The understanding of the relation between humans and the nonhuman world is a major interface between scientific exploration of ecosystems and religious and ethical perspectives. The deep-ecological emphasis on the moral status of whole systems serves as a provocative corrective to the assumption that environmental problems can be best resolved by hierarchical, technocratic thinking. However, such holism raises an important question in environmental ethics: Is the whole system—be it the Brazilian rainforest or the total biosphere of the planet—the overriding locus of value, to which other values, such as the aspirations of individual humans, should be sacrificed? At their most radical such views smack of "ecofascism," and are themselves reductive of the complexity of biological systems. An alternative view is that of Holmes Rolston III, who asserts that the system is valuable because it is the protective matrix within which other sorts of value can be exchanged. Duties to a whole ecosystem, as Don Marietta insists, supplement, rather than supplant, duties to humans and other living things.

Holism is an important ingredient in a network of philosophical and physical explanations; it becomes weakened when its adherents neglect the importance of causative and evaluative explanations in terms of the components of systems.

See also BOUNDARY CONDITIONS; CHAOS THEORY; DOWNWARD CAUSATION; ECOLOGY; EPR PARADOX; HIERARCHY; PHYSICS, QUANTUM

CHRISTOPHER SOUTHGATE