  A discussion of inhomogeneity is indispensable to understand quantum
cosmology, even if one uses the dynamics of homogeneous geometries as a first
approximation. While a full quantization of inhomogeneous gravity is not
available, a broad framework of effective field theory provides important
ingredients for quantum cosmology. Such a setting also allows one to take into
account lessons from the Belinski-Khalatnikov-Lifshitz (BKL) scenario. Based on
several new ingredients, this article presents conditions on various parameters
and mathematical constructions that appear in minisuperspace models. Examples
from different approaches demonstrate their restrictive nature.
