There's an anthropic problem there. Unless you assume humans are alone in a single universe with no branching, or that there are a large number of worlds where

There's an anthropic problem there. Unless you assume humans are alone in a single universe with no branching, or that there are a large number of worlds where an atomic age (as well as any other equivalently stage of dangerous technological advancement) is infeasible, surviving the atomic age tells us that the probability of us surviving events in that reference class is non-zero, but it doesn't tell us much more.