Reduction and emergence in the physical sciences: Reply to Rueger

Abstract

I analyse Rueger's application of Kim's model of functional reduction to the relation between the thermal conductivities of metal bars at macroscopic and atomic scales. 1) I show that it is a misunderstanding to accuse the functional reduction model of not accounting for the fact that there are causal powers at the micro-level which have no equivalent at the macro-level. The model not only allows but requires that the causal powers by virtue of which a functional predicate is defined, are only a subset of the causal powers of the properties filling the functional specification. 2) The fact that the micro-equation does not converge to the macro-equation in general but only under the constraint of a "solvability condition" does not show that reduction is impossible, as Rueger claims, but only that reduction requires inter-level constraints.3) Rueger tries to analyse inter-level reduction with the conceptual means of intralevel reduction. This threatens the coherence of his analysis, given that it makes no sense to ascribe macroproperties such as thermal conductivity to entities at the atomic level. Ignoring the distinction between theses two senses of "reduction" is especially confusing because they have opposite directions: in intra-level reduction, the more detailed account reduces to the less detailed one, whereas in inter-level reduction, the less detailed theory is reduced to the more detailed one. 4) Finally I criticize Rueger's way of using Wimsatt's criteria for emergence in terms of non-aggregativity, to construct a concept of synchronic emergence. It is wrong to require, over and above non-aggregativity, irreducibility as a criterion for emergence.

Emergent agent causation

“…But this does not seem to be an isolated phenomenon. Within the scope of both the physical science itself and its interaction with chemistry we find numerous examples of (non-quantum) irreducible holistic properties (see Anderson, 1972;Leggett, 1987;Gell-Mann, 1994;Cartwright, 1997;Hendry, 2006;Kistler, 2006;Hoffmann, 2007).…”

The Myth of Supervenient Microphysicalism

“…In this sense, if the microphysicalist theory was the only proposal for understanding our concept of the physical, we would have no way to assert, as obviously we do, that the physical holistic levels, along with the chemical and biological, count as paradigmatic physical realms. Now, I have to emphasize the following point: the crucial fact is not that the failure of microphysical supervenience takes us to the conclusion 15 On the empirically plausible failure of microphysical supervenience within the (non-quantum) physical and chemical scopes see also, for example, Primas, 1998, Sklar, 1999, and Kistler, 2006 See, for example, Wimsatt, 2007, Dupré 2012, and Davies 2012.…”