The accepted structure of space and vacuum derives from the results of relativistic cosmology and quantum field theory. It is demonstrated that a chiral interface between enantiomeric regions of a closed universe, or a (right) R-Universe and (left) L-Universe, related by an element of PCT symmetry along the interface, represents a construct with all the attributes required of the theoretical vacuum, in-so-far as quantum behaviour is then seen to be induced by the vacuum interface. Quantum mechanics emerges as a special case of classical mechanics, rather than the latter being a subset of the former. This removes the quantum-mechanical observational problem, explains the cosmological large-number coincidences, and accounts for the anti-matter in the cosmos.