Pre-dawn on the first day of San Francisco’s shelter-in-place mandate, which went into effect March 16, the city sidewalks were empty. By midday, when crowds and chaos are the norm, the city remained eerily quiet. A few joggers took advantage of the open roadways, and I passed a half dozen other people who, like me, were walking dogs.

It is possible that more of us were out than should have been, given recent reports showing very low death rates in an Italian city that instituted a quarantine, and tragically high numbers of deaths in a nearby city that did not. It also seemed clear that most San Franciscans were being good citizens and staying home. That’s why one particular category of city stroller that day surprised me: people who were clearly in their 60s, 70s, and 80s, and probably even in their 90s — the highest risk group for Covid-19. Could they all have been on their way to “provide or receive essential services,” those scant activities allowed under the mandate? I suspected not. It seemed far more likely that they had ignored the pleas from public officials and the medical community that “vulnerable populations” must stay at home.

As a human being, I have a range of reactions to their defiance: concern, frustration, and compassion. As a doctor whose specialty is geriatrics, I try to weigh the many, complicated reasons an older person might be out with the significant reasons they — and all of us — should reconsider going outside. In these unprecedented times, individual liberties are at odds with the well-being of our species, and for most people, old and young, our present is pitted against our future.

Each of the first few days San Franciscans were supposed to stay at home, I passed older adults in uniforms or suits, apparently coming from or headed to work. Others went into our local pharmacy — maybe they live across the digital divide or can’t see well enough to order online. One couple’s location and tense facial expressions made me wonder whether they were going to a doctor’s appointment, worried a new cancer might not get the attention it would have a few weeks earlier — something we doctors worry about, too. Many were also carrying groceries or looked to be out for a walk on a sunny spring day, activities essential for human health and well-being.

As I passed a Starbucks, something caught my attention. Inside were three servers and six customers. All appeared to be in their 20s or early 30s, and I was convinced that I just stumbled upon a certain sort of conversation between them that is also prominent online: “If we get coronavirus, so what? We might not even notice. It’s those old people who will die.”

Then it hit me: those old people. They meant me.

Maybe I am crazy to be out given my age, the dog’s basic needs notwithstanding. I am in my 50s, and one Covid-19 death in my state was a man just one year my junior, albeit far less healthy. My risk, though lower than his, is real. Besides, we know with absolute certainty that both during the 1918 flu pandemic and in recent weeks, places where seemingly draconian social distancing measures were imposed had far less disease and death than those where it was not. Being out makes me a potential vector, an organism able to transmit disease, and puts me at risk of becoming ill myself. With a virus that seems to make people contagious before they are symptomatic, each of us might be the next Typhoid Mary.

On social media, people are taking note of the large numbers of older people across the United States leaving their homes against medical and government advice. Statements along the lines of, My young friends and I are practicing social distancing while old people are partying and signing up for cruises, capture their understandable frustration, but also reflect a lack of insight.

Two reasons why older people may be outside aren’t getting much consideration. The first, which I’ve witnessed often in my quarter-century of experience as a doctor for this demographic, is that they don’t consider themselves old. Although many societies define old age as beginning between 60 and 70, for many people, especially younger and healthier ones, the word “old” carries connotations of frailty, debility, and proximity to death. When those descriptors don’t apply, or when older people perceive them as not applicable, they don’t consider themselves old. As a young geriatrician, I sometimes found this mystifying. As I entered middle-age, I began to understand what patients had told me for years: that their sense of self hadn’t changed, even as the person in the mirror did.

A second unexamined reason elders may be outside is to assert their individual rights. One colleague asks why sentient older adults aren’t allowed to assess and assume their own risk, like younger and middle-aged adults who are permitted to exercise and shop so long as we practice social distancing. I see her point, but human history shows with tragic eloquence that we cannot always trust people — whatever their age or background — to choose the greater good over their own self-interest. In the United States, I imagine another factor may be influencing some elders’ responses to stay-at-home directives: Although the overwhelming majority of older people are cognitively healthy, they are so often portrayed as universally mentally and physically feeble, and we have so little sympathy for people who are differently or not able-bodied, that many are driven to deny their chronological identity in self-defense. Americans have created a culture so ageist that some people may prioritize not being perceived as “old” over their considerable physiologically and immunologically established risk of getting sick and dying from coronavirus.

From her assisted living facility, my 86-year-old mother reported that her friends who still live in their family homes were going out for walks. My parents moved into the facility years ago for my father’s sake, and my mother stayed after his death because, she noted, “I’m not getting any younger.” Now, she was asking whether I thought she, too, could go out — the sky was clear and bright, flowers were in bloom everywhere. I told her I wasn’t sure. With sun and fresh air, a chance to move her body and see other humans, she would feel better. Those simple pleasures will also keep her healthier in the coming weeks and years, because loneliness and immobility are more quickly damaging to elders, and because my mother’s average life expectancy is five years, a statistic that also means she has a 50-50 chance of living longer than that.

But Covid-19 is also more dangerous for older people. And more importantly, there is this: If we all think only of ourselves, the pandemic will spread, and tens or hundreds of thousands of lives may be lost unnecessarily.

My mother did not go out.

Later that day, her facility imposed a lockdown, and I stopped by to pick up her taxes since, unable to go for walks, to her gym, to her classes, or out with friends, she had finished them. But she could not mail them herself. From the facility’s main doorway, she threw the envelope out onto a planter ledge. Feeling guilty, I talked with her only briefly. Like so many adult children of elders, I wondered if I should invite her to move in with us. We are luckier than many because she doesn’t have care needs, simple or advanced. But two of us were sick, and my health system listed several of our symptoms under ‘do not come to work’ stipulations. And since testing is not widely available, we would never know whether we had common colds or coronavirus, so the soonest my mother could come live with us would be two weeks after our symptoms disappeared. And that was a straightforward recommendation. Less clear was what to do about the young nephew who lives with us. Since being asymptomatic is common in his age group, we will never know for sure when it might be safe for my mother to be near him.

My last view of my mother as the door shut was heartbreaking. The door is divided into multiple small window panes. Normally this is pretty; on that day, it resembled the bars of a jail cell. Behind it, my mother looked tiny and sad and brave.

From his social-distancing run a few days into our collective sequestration, our nephew reported that Golden Gate Park was full of people, of all ages, congregating against all governmental, public health, and medical advice. The people in our city’s largest park were behaving as if on vacation, or as if this were an ordinary weekend in ordinary times. It takes some effort to formulate a compassionate response. Don’t they love their parents and grandparents? Don’t they value themselves? Human beings are social animals, but in this case, that instinct appears to be to the detriment of our families, neighbors, and species. After all, it seems likely that most of these same people also have access to smartphones, tablets, laptops, and the know-how to use apps and multiple digital communication platforms to remain social while sheltered.

The same cannot be said for the 1.3 million Americans, or 5 percent of people over age 65, who live in nursing homes, or some of the 1 million Americans in assisted living. They are on lockdown, shut into small rooms or apartments, the able-bodied with few or no direct human interactions, and the disabled restricted to care-related interactions with aides. That many risk hospitalization and death from Covid-19 does not negate several other truths of equal import: that some would choose death over lockdown; that even those who continue to drive, vote, and read have not been given a choice in whether or not to shelter in place; that almost all will suffer adverse health and longevity consequences if such physical and social restrictions are long-lasting, as it seems it will be; and that some will sacrifice their lives, in quality, quantity, or both.

One afternoon, my dog walk took me through a neighborhood of buildings devoted to elders, from senior housing to continuing care communities to nursing homes. All have restricted traffic to a single entrance. I passed three low-income senior apartment buildings and four high-end assisted living high-rises and saw no one. Normally, people and cars come and go, elders can be seen living their lives, a few off to work, many more headed out to exercise, shop, learn, volunteer or play, and some reading on benches in the fresh air. On that day, a huge cardboard box outside the main door to one well-groomed building asked that US mail be deposited there; only staff were allowed to enter.

Already, my geriatrician colleagues and I have begun to hear sad stories: the mother with Alzheimer’s who can’t remember why her family isn’t visiting, though she retains and loudly laments the injury of their absence. The old man without relatives nearby eating as little as he can manage so his food will last. Meanwhile, every day on my dog walks, I pass very old women pushing walkers from which hang bags of groceries. They look terrified when I approach and won’t allow me to offer help. While they live in mortal fear, I get a push notification from our local newspaper that officials are considering closing city parks because of the numbers of people choosing a few hours of fun over the health of their families, friends, and fellow humans.

A few media reports describe unimaginable evil: A Pennsylvania man who deliberately coughed at, then laughed at an old man at a grocery store during ‘seniors only’ hours, when the younger man shouldn’t even have been present. The residents of Italian care homes found abandoned and dead.

But there is also this: communities mobilizing tech and goodwill to help elders. Local and national organizations scrambling to screen, train, and send unprecedented numbers of volunteers to make phone calls, deliver meals, groceries and cards, or develop new online activities for elders and others at high risk for hunger, isolation, and loneliness.

As always, the fortunate remain more advantaged. From her assisted living facility, my mother reports that the chef made the perennial favorite lollipop lamb chops for dinner; the facility’s director went shopping in the early hours, then hand-delivered residents’ requested groceries and pharmacy supplies, and the staff has planned an in-room version of the usual ice cream social for Sunday afternoon.

It has always been true that how we treat our elders determines both the lives of current older people and the futures of the not-yet-old. The pandemic has added new dimensions to that equation, offering daily tests of our individual and societal moral identities, and an opportunity to create a better elderhood today and in the years to come.

Louise Aronson is a physician, geriatrician, writer, professor of medicine at the University of California San Francisco, and the author of the New York Times bestseller Elderhood: Redefining Aging, Transforming Medicine, and Reimagining Life.