In the clashing commentary about whether lockdowns and stay-at-home orders should continue, or whether businesses and stores should be reopened, one senses a yearning for consensus. Why can't everybody just agree? One reason is that we continue to be ignorant on many important points. How many people have been infected with the disease? Some fragmentary evidence has come in, but since many infected people are asymptomatic, no one knows the death rate per infection. How is the virus disseminated in different environments? No one really knows. Some attribute the high number of deaths in New York to transmission in the...