Wolfgang Rindler: Gödel, Einstein, Mach, and Time
AbstractGödel's interest in General Relativity and spacetime was sparked by his friendship with Einstein during the 1940's and 50's at the Princeton Institute for Advanced Study. In particular he came to question the concept of time as "an infinity of layers of 'now' which come into existence successively". Miraculously, and apparently out of nowhere, he produced a possible universe within general relativity that possessed irremovable closed time lines (journeys into one's past), and thus pointed to deep logical paradoxes. Even if our actual universe is not of this kind, Gödel held that the mere possibility of such universes should make philosophers reconsider their views of time. And Gödel's Cosmos had yet another new feature: it was anti-Machian, in the sense that its local inertial reference frames rotated against the bulk matter in the universe. In 1949 this probably surprised Einstein less than it would have done in 1913, when he very respectfully informed the aging and unresponsive Mach that general relativity was Machian.