I can't say I fully understand general relativity, however, one question keeps bothering me . Consider a four dimensional pseudo-riemanian manifold . It has a unique Einstein tensor ,that is divergenceless, therefore can be equivalated to a stress-energy tensor . All well and good . However , I keep hearing about this "block universe" concept . At least in Newtonian mechanics , one infinitesimal "slice" of space- time is sufficient to determine both the future and past evolution of the space time . However , one three-dimensional (infinitesimally 'thick' in the fourth dimension as to contain momentum information) slice of an arbitrary four dimensional manifold is certainly not sufficient to determine the whole manifold . And it is the whole manifold that determines the matter-energy content . It seems to me, the Einstein field equations leave way to many degrees of freedom for a 'block universe' ) . Is there something I'm missing? Some misinterpretation , or some extra constrains on the "universe manifold" or the Stress-Energy tensor?