In May 2023, US Surgeon General Vivek Murthy issued a formal advisory titled Our Epidemic of Loneliness and Isolation, framing chronic loneliness as a public-health emergency comparable in mortality risk to smoking fifteen cigarettes per day. The advisory was the culmination of two decades of accumulating evidence — from Julianne Holt-Lunstad's meta-analyses, from the work of John Cacioppo, from Robert Putnam's civic-decline research, and from Murthy's own earlier book Together — that social disconnection is not a feeling-state to be managed privately but a measurable health input to be addressed at the level of institutions.
The headline mortality figures are by themselves arresting. Loneliness raises the risk of premature death by roughly twenty-six percent. Social isolation raises it by twenty-nine percent. The effects are mediated through cardiovascular disease, stroke, dementia, depression, anxiety, and immune dysregulation. The biological pathways are not speculative; chronic loneliness produces measurable elevations in cortisol, inflammatory markers, and sympathetic nervous-system activity. The body treats prolonged social isolation as a threat condition, and prolonged threat states wear the body down.
Loneliness belongs in the romantic encyclopedia not because it is identical with the absence of a romantic partner — many partnered people are lonely and many single people are not — but because the romantic pair-bond, where it exists, is one of the densest deliveries of the social connection that the literature is measuring. The decline in pairing, the rise in single-person households, the thinning of friendship networks, and the rise in measured loneliness are not separable phenomena. They are the same phenomenon viewed from different angles, and the romantic angle is the one most concentrated for policy purposes because the policy levers around partnering — housing, childcare, work hours, urban form — are concrete.
The 2nd Law — Think — asks for honesty about scale. Loneliness presents as an individual feeling, which invites individual solutions: therapy, self-help, social-skills training, dating apps. These have their place. But the data is on the population, not the individual. The share of Americans reporting fewer than three close friends has tripled in three decades. The share reporting no close friends at all has quadrupled. The share of adults living alone has roughly doubled. These shifts are not the sum of individual choices to be less social; they are responses to changes in the structures — work, family, neighborhood, civic — that used to make social connection a byproduct of ordinary life. Treating the problem at the individual level alone is a category error.
Robert Putnam's Bowling Alone (2000) gave the long-form historical argument: American civic and social capital — the networks of clubs, leagues, churches, unions, and informal gatherings that produced the dense weak ties of mid-century American life — had been in decline since roughly the 1960s. Putnam attributed the decline to a combination of generational replacement (the civic-minded "Greatest Generation" being replaced by less civically active successors), the rise of television, suburbanization, and the entry of women into the paid labor force without a compensating restructuring of household and community labor. Subsequent work has added the internet, the smartphone, the decline of religious affiliation, and the geographic sorting of Americans into politically homogenous communities that no longer share the unstructured contact that produces casual friendship.
The public-health framing matters because it shifts the response from exhortation to intervention. Smoking did not decline because individual smokers were told to want to quit more. It declined because of price changes, public-space regulation, advertising restrictions, and a cumulative cultural shift driven by those structural changes. The equivalent loneliness interventions are not yet built out — they would have to include changes in urban design, in workplace structure, in school programming, in transit, in the regulation of attention-capturing platforms — but the public-health frame at least opens the door to thinking about them at the right level.
Vivek Murthy's advisory was structured around six pillars: strengthen social infrastructure, enact pro-connection public policies, mobilize the health sector, reform digital environments, deepen knowledge, and build a culture of connection. Each pillar is at the policy-and-institution level, not the individual level. This is the right scale. Individuals living through the loneliness epidemic can and should do what they can — call a friend, join a thing, take the lonely person to lunch — but the systemic problem is not solved individually. It is solved, if at all, by rebuilding the contexts in which connection is a side-effect of ordinary life rather than a project that has to be added to an already over-full schedule.
At the romantic scale specifically, the loneliness frame clarifies why the dating-and-marriage decline is not merely a lifestyle shift. The pair-bond is one of the few remaining institutions in which most adults can expect daily, sustained, embodied connection with another human being. When fewer pair-bonds form, when they form later, and when they dissolve more easily, the loneliness consequences are not a side-effect; they are the main effect. The 2nd Law's task here is to keep this connection in view: the romantic data and the loneliness data are reading the same thermometer, and the temperature is rising.