Violation of the weak energy condition in inflating spacetimes

We argue that many future-eternal inflating spacetimes are likely to violate the weak energy condition. It is possible that such spacetimes may not enforce any of the known averaged conditions either. If this is indeed the case, it may open the door to constructing nonsingular, past-eternal inflating cosmologies. Simple nonsingular models are, however, unsatisfactory, and it is not clear if satisfactory models can be built that solve the problem of the initial singularity.