Freiburg 2008 – scientific programme

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AKPhil: Arbeitskreis Philosophie der Physik

AKPhil 6: Wissenschaftstheorie I

AKPhil 6.1: Talk

Tuesday, March 4, 2008, 16:45–17:15, KGI-HS 1015

Why boundary conditions can be laws — •Wolfgang Pietsch — Wissenschaftstheorie, Universität Augsburg

Starting from the underdetermination thesis it is argued, that at least partly the distinction between physical laws and boundary conditions is determined by conventions. Both conceptual and historical evidence will be presented for this conclusion. Conceptually, an analogy will be drawn to Quine's well-known argument concerning the analytic-synthetic distinction. Analytic share with law-like statements the property that, independently of the circumstances, they always hold. In contrast, synthetic statements just like boundary conditions must be deduced from the specific empirical situation. Thus, many of Quine's conclusions derived for the analytic-synthetic distinction apply for the distinction between laws and boundary conditions as well: In particular, the status of a physical statement as law or as boundary condition is not fully determined by the empirical data but also requires well-adapted conventions. With a paradigm shift, statements may switch their status from physical law to boundary condition and vice versa. One historic example concerns the numerical value of the radii of the planets. According to Kepler's astronomy these are determined by law, for Newton they are contingent facts. Where else is the distinction of importance? For instance, Boltzmann's explanation of macroscopic irreversibility presupposes, that an unambiguous line between (reversible) fundamental laws and (irreversible) boundary conditions can be drawn.