I’ll review a new, simpler explanation for the large scale geometry of spacetime, presented in our recent preprint arXiv:2201.07279. The basic ingredients are elementary and well-known, namely Einstein’s theory of gravity and Hawking’s method of computing gravitational entropy. The new twist is provided by the boundary conditions we proposed for big bang-type singularities, allowing conformal zeros but imposing CPT symmetry and analyticity at the bang. These boundary conditions allow gravitational instantons for universes with positive Lambda, massless radiation and positive or negative space curvature. Using them, we are able to infer the gravitational entropy for a complete set of quasi-realistic, four-dimensional cosmologies. If the total entropy in radiation exceeds that of Einstein’s static universe, the gravitational entropy exceeds the de Sitter entropy. As the total entropy is increased,  the most probable large-scale geometry for the universe becomes increasingly flat, homogeneous and isotropic. I’ll briefly summarize recent progress towards elaborating this picture into a fully predictive cosmological theory.