The goal of probabilistic seismic‐hazard analysis (PSHA) is to summarize the rates of seismic ground‐motion hazards at a site. The basic assumption is that true hazard curves exist to express the exceedance rates of any ground‐motion amplitude at a site. Procedurally, PSHA depends on a complete and accurate description of seismicity combined with a model for ground motions using standard probabilistic methods to estimate the hazard curve. The hazard curve can be improved by improving inputs and by identifying and then resolving inconsistencies between observations and estimated hazard. However, these inconsistencies do not invalidate the existence of the hazard curve or the probability theory used to estimate it.