In fact Diana thought Adam’s long article on peak oil was so-so, something someone else could have written. She seems to prefer romanticizing him as some genius. Now, however, she is glad to have read it.

“Even then, though, come on.” Sam is flustered by his older sister trespassing into the boys’ club. “It’s not like there’s a lack of energy. Even just the tides — there’s all the energy we could want.”

Diana says nothing about the difficulty there must be in making the least use of the waves. She just says: “I don’t know.” The complexity of the world sometimes feels to her like an index of its fragility, and a tremor of very ill-defined social or political dread flutters through all these leaf-cluttered summer days, with the flags asleep on their poles.