Berlin 2015 – scientific programme

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AGPhil: Arbeitsgruppe Philosophie der Physik

AGPhil 7: The role of geometry in gravitational theories

AGPhil 7.3: Talk

Thursday, March 19, 2015, 12:15–12:45, A 060

The neighborhood of General Relativity in the space of (spacetime?) theories — •Dennis Lehmkuhl — IZWT, University of Wuppertal, Einstein Papers Project, Caltech

How `special' is General Relativity (GR) as compared to other theories? The answer to this question depends on what other theories we compare GR to: other field theories or just other spacetime theories? I will argue that Einstein himself saw GR not primarily as a theory of spacetime, but as a field theory unifying gravity and inertia. I will then show that his interpretation of GR as a unification of gravity and inertia is only possible because of the way the different fields couple in GR, and compare GR to a much later theory (Jordan's theory from the 1950s, the first scalar-tensor theory). The comparison will show that it is the coupling structure that ensures the motion of particles on geodesics, and thus the possibility for Einstein to interpret the theory as a unified field theory (of gravity and inertia).