Philosophy of Physics Seminar (Thursday - Week 5, HT23)

Philosophy of Physics

Toward the end of 1919, in a two-column contribution for the Times of London, Einstein famously declared relativity theory to be a 'principle theory,' like thermodynamics, rather than a 'constructive theory,' like the kinetic theory of gases. This distinction has attracted considerable attention in both the historically- and the theoretically-oriented scholarship. As it turns out, its popularity has somewhat hindered the appreciation of its core message. This paper hopes to show that to properly understand Einstein's 'theory of theories,' one has to disentangle the two threads of its fabric, the context of justification, and the context of discovery. The expression ‘theory of principles’ indicates (a) a class of existing theories: principle theories do not entail physical laws, but put constraints on them. Law-like statements do not qualify as physical laws unless they satisfy such constraints (b) a strategy for finding new theories: instead of searching directly for the laws of nature, first one should search for constraints the limit the number of possible candidates. As it is well-known, the current debate about the foundation of spacetime theories has taken the form of the opposition between the geometrical and the dynamical approach. In both cases, relativity theory is ultimately treated as a constructive theory: a constructive theory of the material structure of rods and clocks (Brown) or a constructive theory of the geometrical structure of spacetime (Janssen). The historical material presented will show that the geometrical/dynamical opposition does not capture the critical difference between the Einstein/Minkowski and Lorentz/Poincaré approach. What both the geometrical and dynamical approach fails to grasp is the peculiar modal status of Einstein’s new kinematics, which is not only a factual but also a normative claim. The paper concludes that special relativity is indeed, better characterized as a principle theory.


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If you wish to join the dinner proceeding the talk, please email Henrique:

Philosophy of Physics Seminar Convenors for HT23: Oliver Pooley, Patrick Duerr and Henrique de Andrade Gomes  | Philosophy of Physics Group Website