  We compare the recent loop quantum cosmology approach of Bojowald and
co-workers with earlier quantum cosmological schemes. Because the weak-energy
condition can now be violated at short distances, and not necessarily with a
high energy density, a number of possible instabilities are suggested: flat
space unstable to expansion or baby universe production. Or else a Machian type
principle is required to prevent such behaviour. Allowing a bounce to prevent
an approaching singularity seems incompatible with other standard notions
concerning the arrow of time and unitarity.
  Preventing rapid oscillations in the wavefunction appears in conflict with
more general scalar-tensor gravity.
  Other approaches such as ``creation from nothing'' or from some quiescent
state, static or time machine, are also assessed on grounds of naturalness and
fine tuning.
