  We argue that the choice of boundary condition for the wave function in
quantum cosmology depends on the UV completion of general relativity. We
provide an explicit example using a braneworld scenario in which a de Sitter
cosmology is induced on the surface of a Coleman-de Luccia bubble in a
5-dimensional AdS space. The corresponding boundary conditions are unambigously
fixed by demanding consistency with the known physics of bubble nucleation and
this selects the Vilenkin weighting for the amplitude from a 4D viewpoint.
