The spherical cow problem

Do our ideas reflect the world as it is, or merely as we theorize it to be?

There is an old joke, variations of which have long circulated. It goes like this: there once was a farmer whose cows had stopped producing milk. The farmer tried everything but could not manage to solve the problem. She tried altering the cows’ diet, she tried putting them in a new pasture, she tried enlisting the help of the local vet—all with no success. Finally, she took one of the cows to a world-renowned university located in her state. The university was home to some of the brightest contemporary minds; surely, they could help fix her malfunctioning livestock? The professors were indeed willing to help, leaping at the chance to tackle a difficult challenge. They agreed to examine the cows and apply their know-how to finding a way to return the herd to milk production. They spent weeks on the problem, making calculations, running various milk-production models, and consulting with researchers at other universities. When they had finished, the farmer returned to hear what they had come up with. Had they solved the problem? “Yes,” said the lead researcher. “We have found a surefire way to increase milk production. First let us assume we have spherical cows in a vacuum.”

This story pokes fun at the tendency of some who work in the idea space to embrace solutions which, while perhaps workable in theory, do not necessarily apply in the real world. The researchers were a collection of world-class minds, their methods cutting-edge, yet they managed to produce a solution which was, to anyone not ensconced in their bubble, not particularly helpful.

Having spent the past 20 years in the academic arena, I have always tried to remember this metaphor, hoping it can ground me in the real world, which universities are often far from. I have, in full disclosure, written my fair share of spherical cow papers, built on infeasible assumptions. But I have found myself coming back to the cow story more and more lately, feeling that this is increasingly a problem we face in public health in a time of COVID-19, where we are advocating for solutions based on theoretical assumptions that do not always meet the practical demands of reality.

By way of example, I thought I would address the notion of “No-COVID” that has made the academic rounds recently, suggesting that we can get to a place where we reduce COVID cases to zero. The general idea is to create COVID-free “green zones” by eliminating the disease in different regions. One by one, these regions could then be merged, creating a country free of the disease. The fundamental idea of course is that we prioritize ongoing social restrictions until we achieve either elimination of COVID, or New Zealand-like low endemicity, as a priority for social action. Now you may well ask: how could anyone find fault with such a goal? Are we not all working towards the aim of a COVID-free world? Yes. But there is a substantial difference between using the goal of a COVID-free world to motivate success in addressing the disease and defining success against COVID as the complete eradication of the virus. The latter goal is easy to endorse in principle, but what are its implications? It would take lockdowns, mask mandates, and social conformity on a level rarely seen during this pandemic. It would take massive government funding, vastly larger in scale than what has been devoted to mitigating the effects of the pandemic, to keep these steps from being ruinous. It could include the cost of worsening substance misuse, drug overdose, and poor mental health, with more data coming out showing the record high rates of mental illness, particularly among younger persons, who will live with the consequences over the lifecourse. It would also take a change in human nature, as millions would have to ignore their instinct to rebel against the strictures necessary for getting to, and maintaining, zero COVID cases. And it would take focus away from addressing the health disparities exploited by COVID, as our pursuit of zero cases diverts attention from the more urgent, and doable, task of reducing cases among the socioeconomically marginalized communities the disease has hit hardest.

Recently, Nature asked over 100 immunologists, virologists, and infectious disease researchers for their thoughts on whether COVID could be eradicated. Nearly 90 percent of respondents expressed the opinion that it will become endemic, possibly lingering for years to come. If this happens, it will be critical that we do not allow COVID to become a disease of the marginalized, circulating among communities whose health is already vulnerable. Bringing COVID under control through vaccination so that life can resume, and making sure that whatever remains does not disproportionately affect a marginalized few, should be our goal, at least in the near-term. Ramping up vaccination, focusing on the most vulnerable communities will take significant public buy-in, which, after the exhaustion of this last year, could be hard to maintain, especially as vaccines allow more people to put COVID out of mind. If we exhaust public engagement through the vain pursuit of zero cases, we will have fewer resources—emotional, psychological, financial—to apply to the challenges at hand. Ending the acute phase of the pandemic represents a steep hill to climb. Rather than try to roll a spherical cow up it, we should engage with the practical realities of the disease. We can do this by pursuing a future where COVID may well remain with us, but in a manageable form. We should save our energy and focus for this task.

I should say that I am not talking about the spherical cow problem to suggest public health is somehow out of touch or that we do not understand our own field. We do not suggest impractical solutions out of detachment from reality; on the contrary, we often turn to them from an abundance of data and a desire to apply knowledge and good intentions to making the world healthier. It is, however, this very desire that can at times lead us astray. It strikes me that we sometimes misfire with our proposed solutions simply because that is where our good intentions lead us. The goal of “No-COVID” is attractive because it speaks to the kind of world we all wish to create: one that is free of disease. And as a long-term aspiration for our field, this is indeed the goal we should have. But as a specific benchmark for managing a crisis in a context of finite energy, resources, and political will, it has the potential to be counterproductive, a classic example of making the perfect the enemy of the good.

In this context, “zero-COVID” is arguably the quintessential spherical cow. Fundamentally, is a 111-day Melbourne-style lockdown really feasible again anywhere else? From where many of us sit—in positions of relative privilege, working in the field of ideas—it makes sense to embrace this slogan with all its implications. But this easy radicalism can elide the full complexity of the problem—the many shades of grey involved in containing an outbreak and allowing space for living, working, and the functioning of the economy. What is more, there is much in contemporary public health to discourage acknowledging this complexity. At a time when we have been thinking about COVID-19 and not much else for more than a year, taking a nuanced view of how to deal with the pandemic runs the risk of appearing to side with the most reactionary forces in our society, even to be dismissing COVID. Yet, nothing could be further from the truth. The challenges that we have faced addressing COVID and mitigating its other consequences (on the economy, mental health, etc.) make it all the more important that we engage with the complexity of these issues. Anything less could mean not thinking hard enough about how we can best make it through a global pandemic, with our world intact.

There is, of course, a case to be made that the point of calling for solutions like zero COVID is not so much to enact policy but to change the conversation around issues. Proposing radical solutions could be seen as a means of moving the Overton Window in a more constructive direction; in this case, toward a more robust engagement with doing what needs to be done to protect us all from COVID.  

But is there a cost to this? When there is a clear disconnect between proposed solutions and the lived experience they are meant to address, there is a danger of alienating people who might otherwise join a coalition for action. For example, there are likely many people who would support taking some fairly drastic steps to ensure that no one unnecessarily contracts COVID, but who are not willing to accept the notion that we need to continue lockdowns when COVID is associated predominantly with milder cases, much less mortality. When risk abolition is seen as a prerequisite for supporting a better status quo, these people—many of us—may opt out of the movement. By focusing solely on risk abolition instead of targeted risk reduction, we may lose valuable time and support in our efforts to improve health.

I realize these reservations may mark me as overly grounded in the world as it is, while the moment we are in seems to demand a more radical approach. I am trying to reflect, however, less on political exigencies than on the basic facts of human nature. When we feel we are being asked to take certain steps based on an incomplete view of reality, we are likely to resist these steps and distrust the people proposing them. When we propose solutions predicated on the existence of spherical cows and are not open to discussion, we do not just run the risk of looking silly. We run the risk of being ineffective. This is something we cannot afford.

Having said all this, I conclude with what is perhaps a twist: I am not arguing we should stop proposing solutions that call for spherical cows. I am proposing we stress test them. I am proposing that we engage in dialogue about what solutions are possible, keeping an open mind about a plurality of perspectives. We should strive to a maximally better world—yes, one without COVID—but also one that acknowledges the realities and complexities of existence, of nature. To do that best we should remain in conversation, constantly, about what that looks like and how to get there. The public conversation about health is too important not to include as many passionately advocated solutions as possible. But its importance also demands our willingness to set these ideas against each other, to have a full and open debate about their merits, so that we may sharpen them and select the ones that are best. This means seeking out counter-narratives to our ideas, particularly when these ideas start to become orthodoxies. It means starting conversations with the assumption of good faith, even with the knowledge that this faith will be occasionally misplaced. It means tolerating divergent viewpoints in public health, accepting that there is room for disagreement in our field, and recognizing that that disagreement, even with profoundly compelling ideas like zero COVID, is grounded in reason and careful thought, aspiring to a better world, within the bounds of what is feasible. 

It means always asking: do our ideas reflect the world as it is, or merely as we theorize it to be? Much depends on the answer.

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Also this week.

In this week’s The Turning Point, Michael Stein and I write about one of my favorite topics: the challenge public health faces in balancing the — sometimes — competing demands of equity and efficiency.  Never has this been more apparent than during this time of COVID-19 vaccination.