1. Three Types Of Reductionism

In 1974, Francisco Ayalaidentified three distinct types of reductionist theses: 1) Methodological reductionism is both a research strategy for studying wholes, such as cells, in terms of their parts, such as macromolecules, and for applying successful theories in one area, such as Darwinian evolution, to other areas, such as sociology or religion. 2) Epistemological reduction is the claim that processes, properties, laws or theories found in higher levels of complexity, such as the neurosciences, can be derived entirely from those found in lower levels of complexity, such as biology, and, ultimately, physics. 3) Ontological reductionism is the view that higher-level, more complex entities are nothing but complex organizations of simpler entities, i.e., the whole is ‘nothing but’ the sum of its parts.

Ayala’s analysis has been widely used in theology and science beginning as early as 1976, when Peacocke gave an extensive treatment of reductionism.. In a recent essay, Murphyhas added a fourth type: 4) Causal reductionism asserts that all causes are ‘bottom-up’; the characteristics and processes of the parts entirely determine those of the whole. She has also clarified an ambiguity in Ayala’s description of ontological reductionism. According to Murphy, ontological reductionism per se is the view that “no new kinds of metaphysical ‘ingredients’ need to be added to produce higher-level entities from lower (-level ones).” It rejects the existence of ‘vital forces’ or ‘entelechy’ in the life sciences, as well as mind or soul as the basis of consciousness. Murphy then adds a fifth type of reductionism: 5) Reductive materialism is a stronger claim than ontological reductionism, insisting that “(only) the entities at the lowest level are really real; higher level entities ... are only composite structures made of atoms.” We can thus reject reductive materialism by arguing that higher-level entities are ‘as real as’ the entities that compose them, and we can do so while agreeing with ontological reductionists in rejecting vitalism and other ontological dualisms.

Contributed by: Dr. Robert Russell