Jeffrey Bloom begins his fine essay with a discussion of a form of addiction that has lately been the subject of widespread worry: the addiction of many Americans, and especially many younger Americans, to their “screens.” As a behavioral addiction, in contrast to the much more serious plague of chemical addiction to drugs, it is also easier to ridicule or dismiss. But Bloom devotes some enlightening paragraphs to a recent book detailing its gravely debilitating effects on the lives of those caught in its snare and, alarmingly, to the ways in which (in his words) “the feedback mechanisms of social media” and video games “are engineered [my emphasis] to erode self-control”—in other words, the ways in which whole industries implicitly collude in the creation of more addicts.