Christopher Nolan’s film, “Oppenheimer,” which opens in theaters on July 21, highlights a value judgment that the Manhattan Project scientists had to make before Trinity, the test of the first atomic bomb.

As mask mandates are rolled back and friends and neighbors debate the risks and benefits of masks and the merits or permissibility of mandating their use, we can catch a glimpse of the considerable extent to which values depend heavily on something other than pure reason. It’s a bit disappointing, perhaps. But it might be a useful lesson for democracy.