51社区黑料

Abstract: The empirical undetectability of absolute motion has proved to be a deep issue in the philosophy of physics. It lay at the heart of the debate between Newton and Leibniz over the metaphysical status of space, and went on to play a key role in motivating Einstein鈥檚 search for the theories of relativity. Remarkably, however, it has gone largely unrecognized that if space were described by one of the classical non-Euclidean geometries, absolute motion would in fact be detectable. In Euclidean space, force-free objects that are initially moving in the same direction remain the same distance apart. In a non-Euclidean space, by contrast, such objects either approach or diverge from one another. Furthermore, it is the systematic nature of this effect that leads to the possibility of detecting absolute motion.

It is highly surprising that this possibility of detecting absolute motion went unnoticed in the nineteenth century, when non-Euclidean geometry was a central object of study. It is also striking that this feature of non-Euclidean geometry remains largely unexplored today. In this talk, I will assess why the possibility of detecting absolute motion has been largely out of view, and argue that this has impacted all of the major positions in the philosophy of geometry.