In Ulam and von Neumann’s original sense, the singularity is the ultimate black swan event, not to be predicted from anything that came before, and “beyond which human affairs…could not continue.” The singularity could be another name for doomsday.

William Poundstone, The doomsday calculation: How an equation that predicts the future is transforming everything we know about life and the universe, New York, 2019, p. 207