The case of the vanishing wavefunction.

Spacetime singularities are often held to be pathologies which need to be resolved, and researchers working on the foundations of physics often pin their hopes on the elusive quantum theory of gravity to offer a way to resolve singularities. What is less agreed upon is what such a resolution would amount to: what criteria would a theory of quantum gravity have to fulfill to resolve spacetime singularities? In this paper, I critically analyze one criterion proposed within canonical quantum cosmology for the avoidance of the big bang singularity, to draw philosophical lessons about how to interpret such criteria. The criterion, when applied to symmetry-reduced cosmological models, claims to avoid the big bang by making the wavefunction of the universe vanish 'at' the singularity.