  Typically, a less fundamental theory, or structure, emerging from a more
fundamental one is an example of synchronic emergence. A model (and the
physical state it describes) emerging from a prior model (state) upon which it
nevertheless depends is an example of diachronic emergence. The case of
spacetime emergent from quantum gravity and quantum cosmology challenges these
two conceptions of emergence. Here, I propose two more-general conceptions of
emergence, analogous to the synchronic and diachronic ones, but which are
potentially applicable to the case of emergent spacetime: an inter-level,
hierarchical conception, and an intra-level, `flat' conception. I then explore
whether, and how, these ideas may be applicable in the case of several putative
examples of relativistic spacetime emergent from the non-spatiotemporal
structures described by different approaches to quantum gravity, and of
spacetime emergent from a non-spatiotemporal `big bang' state according to
different examples of quantum cosmology.
