New Delhi, Sept. 9 -- Despite their talent in predictive analytics, none of the experts predicted that a pandemic would bring the whole world to a stand-still for months on end. No model predicted that a national lockdown would force millions of people to walk thousands of kilometres. No one predicted that wearing a protective mask would become a political issue.

Even after several months of the covid pandemic, we still do not know how many more people will get infected, or if those once infected could catch the virus again. We do not know when a vaccine will offer relief or how many people around the world will get vaccinated. We have far too many unanswered questions about covid-19.

A recent book, Radical Uncertainty: Decision-Making ...