The vulnerable world hypothesis or the "black ball" hypothesis refers to the idea that civilizations may likely be destroyed by some disruptive technologies (a black ball) unless extraordinary measures are taken against the scenario from happening. The philosopher Nick Bostrom introduced the hypothesis in an initial publication in 2019 in the journal Global Policy and later further discussed in a 2022 essay published in Aeon along with co-author Matthew van der Merwe. The hypothesis is quoted in discussions about the safety of advanced technologies.