Berlin 2012 – wissenschaftliches Programm

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AGPhil: Arbeitsgruppe Philosophie der Physik

AGPhil 1: "Condensed Metaphysics" I: Reduction and Emergence

AGPhil 1.2: Hauptvortrag

Montag, 26. März 2012, 10:15–11:00, E 020

Why is More Different? — •Margaret Morrison — University of Toronto

Emergent phenomena are typically described as those that cannot be reduced, explained nor predicted from their microphysical base. However, this characterization can be fully satisfied on purely epistemological grounds, leaving open the possibility that emergence may simply point to a gap in our knowledge of these phenomena. By contrast, Anderson's (1972) claim that the whole is not only greater than but very "different from" its parts implies a strong ontological dimension to emergence, one that requires us to explain how, for example, superconductivity can be ontologically distinct from its micro-ontology of Cooper pairing. This is partly explained by using RG methods to show how the 'universal' characteristics of emergent phenomena are insensitive to the Hamiltonian(s) governing the microphysics. But this is not wholly sufficient since it is possible to claim that the independence simply reflects the fact that different 'levels' are appropriate when explaining physical behavior, e.g. we needn't appeal to micro properties in explaining fluid behavior. The paper attempts a resolution to the problem of ontological independence by highlighting the role of spontaneous symmetry breaking in the emergence of universal properties like infinite conductivity. If we focus on the dynamical aspects of symmetry breaking rather than interpreting it as an organizing principle (Laughlin and Pines, 2000) we are able to see how it, together with the RG arguments, illustrates both how and why emergent phenomena can be considered different from their micro-constituents.