This is a form of indeterminism first highlighted by Earman and Norton (1987) as an interpretive philosophical difficulty for realism about GTR’s description of the world, especially the point manifold M. They showed that realism about the manifold as a part of the furniture of the universe (which they called “manifold substantivalism”) commits us to an automatic indeterminism in GTR (as described above), and they argued that this is unacceptable. (See the hole argument and Hoefer (1996) for o