Nearly two years into a global pandemic, uncertainty has profoundly unsettled both our personal and political lives. Some of its sources are epistemic: How long will vaccine immunity last? Others are sharply existential: Will I see my loved one again?

Uncertainty is perhaps never more consequential than where it intersects with political power. Leading this issue’s forum, Sheila Jasanoff, pioneering scholar of science and technology studies, argues that public policy could benefit from a much more serious acknowledgment of uncertainty.