TRADITIONS IN COLLISION: THE EMERGENCE OF LOGICAL EMPIRICISM BETWEEN THE RIEMANNIAN AND HELMHOLTZIAN TRADITIONS Marco Giovanelli This article attempts to explain the emergence of the logical empiricist philosophy of space and time as a collision of mathematical traditions. The historical development of the “Riemannian” and “Helmholtzian” traditions in nineteenth-century mathematics is investigated. Whereas Helmholtz’s insistence on rigid bodies in geometry was developed group theoretically by Lie and philosophically by Poincaré, Riemann’s Habilitationsvotrag triggered Christoffel’s and Lipschitz’s work on quadratic differential forms, paving the way to Ricci’s absolute differential calculus. The transition from special to general rela- tivity is briefly sketched as a process of escaping from the Helmholtzian tradition and en- tering the Riemannian one. Early logical empiricist conventionalism, it is argued, emerges as the failed attempt to interpret Einstein’sreflections on rods and clocks in general rela- tivity through the conceptual resources of the Helmholtzian tradition. Einstein’sepiste- mology of geometry should, in spite of his rhetorical appeal to Helmholtz and Poincaré, be understood in the wake the Riemannian tradition and of its aftermath in the work of Levi-Civita, Weyl, Eddington, and others. 1. Introduction In an influential paper, John Norton (1999) has suggested that general relativity might be regarded as the result of a “collision of geometries” or, better, of geo- metrical strategies. On the one hand, there is Riemann’s “additive strategy,” which Contact Marco Giovanelli at Universität Tübingen, Forum Scientiarum, Doblerstraße 33, 72074 Tübingen, Germany (
[email protected]). Except where noted, translations are by M. Giovanelli for this essay.