Increasing loneliness is a popular symptom of modern society’s decline, and it is often attributed to the loss of traditional family ties. Panicked talk of a “loneliness epidemic” in Western societies rests on shaky foundations, however. The model of the large, close-knit family was not “normal”; it mostly arose from the historical anomaly of the 19th century’s demographic explosion. Moreover, concerns about widespread loneliness were already in circulation the 1800s—the very period of social formation whose disappearance was supposed to be the reason for increased loneliness today. The incoherence points to a central misunderstanding of the psychosocial causes of loneliness. In most cases, feelings of loneliness have less to do with the absence of social bonds than with the negative qualities of existing relationships. In reality, modernization increased the structural control individuals had over their lives, friendships, partnerships, and family relations. But it also increased the number of relationships that could be terminated at will. The intimate sphere became subject to dynamic changes whose paradoxical result was that as experiences of loneliness grew rarer, the threat of social isolation increased. The epidemic we face in our current age is not loneliness but its fear.