Teen-agers are cyborgs, and their phones are mechanical eyes that help them interpret their experience. “To document,” Jurgenson writes, “is to be involved with our own experience instead of passively letting it float by.” On this subject, Jurgenson has all the right, if somewhat dutiful, opinions: nostalgia is overrated, but he’s not into “digital austerity.” We shouldn’t hark back to an era in which we were less attached to technology—mostly because that era doesn’t exist.