Perhaps it was the economic system that had convinced her that “not new” meant “not good enough.”… At 11:47 p.m., Aya’s smartphone reached 9 percent. She was sitting on the last train home, watching a video while the city slipped past the window in fragments of fluorescent light. The phone itself was extraordinary. Its processor contained billions of transistors. Its camera computationally combined multiple exposures in milliseconds. Its neural engine could translate speech, remove objects from photographs, summarize documents, and recognize faces. Yet the little battery beneath the glass remained the weak point. Aya had bought the phone three years earlier. When it was new, a full charge lasted almost two days. Now, on a normal day, she charged it twice. She had already replaced the battery once. Her father, who repaired electronic equipment for a living, used to laugh at this. “We can make a computer powerful enough to process an enormous amount of inform...