  Twenty years ago, by extending the Wightman axiom framework, it has been
found possible to quantize only a conformal factor of the gravitational field.
Gravitons being excluded from this quantum scalar field theory, numerous
attempts were done to give a valuable description of what could be quantum
gravity. In this talk we present a familly of Lorentz manifolds which can be
foliated by isotropic hypersurfaces and pose severe restrictions on the form of
the energy-momentum tensor in Einstein's equations. They can be associated to
gravitational waves "without gravitons" in a vacuum described by two
cosmological functions, but not to a massless particle flow. From this
cross-checking with the previous remark, a "very" primordial quantum
cosmological scenario is proposed.
