Humans didn’t really have any species-level concerns up until the 20th century. There was simply no reason to think that way—history was a succession of nations, states, and peoples, and they were all at war with each other over resources or who inherits what or which socioeconomic system to have.

Then came the atom bomb.

Immediately it was clear its power necessitated species-level thinking, beyond nation states. During World War II, when the Target Committee in Los Alamos made their decisions of where to drop the bombs, the first on their list was Kyoto, the cultural center of Japan. But Secretary of War Henry Stimson refused, arguing that Kyoto contained too much Japanese heritage, and that it would be a loss for the world as a whole, eventually taking the debate all the way to President Truman. Kyoto was replaced with Nagasaki, and so Tokugawa’s Nijō Castle still stands. I got engaged there.