It had been my understanding that the big bang model of the universe is a theory of the origins of the structure of the universe in which the expansion of the universe is extrapolated back in time until we arrive at a near-singularity and general relativity breaks down. Accordingly, the big bang theory starts when general relativity begins to work, and before that anything could be the case and still be consistent with the big bang model. In my reading of the physics literature this seems to be the case. However, isn't this inconsistent with the interpretation of big bang cosmology in which spacetime is created? For instance, it may be asked what happened before the big bang. Which is the better answer?--That nothing happened because the big bang involves the creation of time which nevertheless general relativity can say nothing about? Or is it better to say that there was a singularity before the big bang and that what happened before is debatable. I am asking this because science writers like Paul Davies (1978, 'Spacetime singularities in cosmology') will say things like the following: "If we extrapolate this prediction to its extreme, we reach a point when all distances in the universe have shrunk to zero. An initial cosmological singularity therefore forms a past temporal extremity to the universe. We cannot continue physical reasoning, or even the concept of spacetime, through such an extremity. For this reason most cosmologists think of the initial singularity as the beginning of the universe. On this view the big bang represents the creation event; the creation not only of all the matter and energy in the universe, but also of spacetime itself." But to me, this is either untrue or at least a misleading overstep on the actual content of the the big bang model. So isn't it true that: 1. The big bang model begins when general relativistic effects allow the evolution of the universe to be predicted. 2. The big bang model would still remain if it was determined that time extends beyond the origin of the universe. Lastly, do theories which attempt to explore the earlier pre-universe, or mutliverse, or universe creation via brane collision, etc. assume that time extends further back, or was time still created before (or at) the big bang?