Why is theory relevant to a public health of consequence? Because theory stands at the crossroads of imagination, observation, metaphor, insight, and action.1 Theory, literally inward sight (per its original ancient Greek etymology1) is what enables researchers, practitioners, and activists alike first to “see” the dots before we can even “connect” them, let alone speculate about or address potential causal processes that create the observed connections and patterns. The most fervid debates in public health (and other sciences) are rarely about “the facts” but rather their explanation. For example, none would dispute, 100 years ago or today, that the on-average life expectancy is shorter among people in the United States classified as Black versus White (quibbles over the margins of error affecting these estimates notwithstanding); by contrast, controversies have raged, then and now, over whether this pattern reflects biological or cultural inferiority versus social injustice.1
Theory is vital to adducing cause and to conceptualizing and envisioning structures and systems that shape health but which lie outside of what a physical scale can measure or an unaided eye can see.1,2 Consider the theoretical proposition that the primary drivers of population health and health inequities are to be found within our body politic, not within our bodies.1 Of course measurable aspects of biology are involved—but it is hypotheses spurred by theory that allow for discriminating between explanations open to understanding these biological parameters as biological expressions of societal conditions, versus as innate characteristics that govern our fate.
Theory invites us to think with metaphors, to spark new connections in our pattern-seeking minds.1 In the case of work on racism and health, for example, I have found that the conceit of “crossroads,” crossed with theory, can be consequential in at least five ways.2
First, crossroads reminds us to be interdisciplinary or transdisciplinary. While my work linking racial injustice to population health is grounded in epidemiology, that is, the study of distributions and determinants of health and disease in populations, I necessarily draw on other disciplines and their theories, including history, biology, sociology, psychology, statistics, and philosophy of science, to name but a few.1,2
Second, crossroads, by definition, imply and create boundaries, and my work, like all work in the population sciences, confronts thorny questions of conceptual, social, and spatial boundaries, such as defining who and what makes “populations” (say, in relation to race/ethnicity, social class, gender, sexuality, or nationality), and also who and what makes a “neighborhood” or “nation.”1–3
Third, crossroads involve junctures and journeys. Interwoven and interacting societal, biological, and ecological systems are central to how I conceptualize “embodiment,” one of the core constructs of the ecosocial theory of disease distribution I have been developing since 1994.1 By embodiment, I mean how people literally embody, biologically, the multilevel dynamic and coconstituted societal and ecologic context within which we live, work, love, play, fight, ail, and die, thereby creating population patterns of health, disease, and well-being within and across historical generations. Of note, the main metaphor of ecosocial theory evokes crossroads, because it interleaves two fractal structures that span from macro to micro: the ever-evolving tree, or rather, bush of life, and the historically forged scaffolding of society that different societal groups daily seek to reinforce or alter, via strengthening or challenging the status quo. Imagine, for example, a vine weaving its way in and out across the surface of a chain-link fence, and see that self-same structure repeated, at myriad scales and levels, from the global to the subcellular. The plethora of crossroads should be apparent—as should how societal conditions shape options for organisms and species to thrive or perish, as the global emergency of climate change makes all too clear.
Fourth, crossroads, by definition, are branched structures, a form critical for understanding probabilities, and our work in public health grapples with the interplay of structure and chance as they jointly shape individual risk and population rates of disease.3 It is no accident that a predilection for playing with chance and contingency is a key feature of the myriad gods, goddesses, and mythical figures associated with or worshipped at the crossroads, whether Hermes and Hecate in ancient Greece, Eshu among the Yoruba in Nigeria and his counterparts worldwide among the slavery-driven African diaspora, Loki in the Nordic realms, or Coyote or Raven among different North American Indigenous peoples.4 Neither fate nor luck has the last word; theory gives us the vision and responsibility to create equitable societies that proportionately increase the odds, in relation to injustice and need, for all to live healthy and dignified lives.
Fifth and finally, the work of public health is itself located at the crossroads of science and society. I mean this in two ways. The first refers to the social production of science and the social responsibilities of scientists; notably, the field-shaking 1931 conference compendium that introduced these ideas to the field of history of science and technology studies was called “Science at the Crossroads.”5 The second refers to how societal change and the work of public health alters the very phenomena we study and the scientific problems we need to solve. Such a reflexive and consequential understanding of our theories and practice infuses Winslow’s visionary 1926 article “Public Health at the Crossroads,”6 initially given as a presidential oration for the American Public Health Association, and in which he broke new ground by raising the public health, medical, and social implications of the US and European decline in infectious disease mortality rates and the corresponding growing burdens of chronic noncommunicable somatic and mental ailments.
In summary, a theoretical vantage is crucial to seeing and appraising evidence. In the case of racism and health, it is what allows us in public health to propose that police killings and police deaths be counted as public health data, rather than solely as criminal justice data, so as to increase accountability and the likelihood of prevention.7 It is what reminds us that Jim Crow is with us still, as embodied history, since every person born in the United States before 1965, that is, aged 50 years and older, was born when Jim Crow was the law of the land in 21 US states, with birth conditions affecting not only their adult health status and mortality but their children’s health as well.2 It is what fosters research on associations between implicit and explicit measures of exposure to racial discrimination, racialized economic segregation, and adverse health status2—and makes clear there is nothing “distal” about structural discrimination because it is intimately encountered and embodied, day in and day out.1–3 Ultimately, to challenge the still dominant ahistorical and decontextualized biomedical and lifestyle theories of disease distribution, which reduce causes of disease to individuals’ genetic constitution and “personal tastes”1 and deem it “political” to address racism and health, as if ignoring this issue were not equally political, we need theory. Why? Because it affords us alternative frameworks to analyze, in context, population health and health inequities as embodied history, revealing the workings of structured chance3 in our jointly biophysical and social world—a crossroads if ever there were one.
All of us, all people, are born, live, and die at these crossroads. To alter the odds, for good or for ill, of who ails and dies of what conditions at what age requires concerted conscious action, informed by theory. Informing the consequences of these actions are the theories and values prioritized: think only of the clean water fights of the mid-19th century CE that galvanized the modern public health movement,1 or the clean water fight now under way in Flint, Michigan, where government depravity in cost-cutting—led by elected and appointed officials, and simultaneously aided and fought by differing factions within state public health and environmental agencies—resulted in contaminating the city’s water, with its largely Black and low-income residents now relying on bottled water and fearing for the long-term consequences of lead poisoning of their children.8 A public health of consequence knows that reactionary politics and policies will magnify health inequities, progressive politics and policies can help eliminate them. These are the crossroads at which we presently stand.
ACKNOWLEDGMENTS
Preparation of this article was in part supported by the American Cancer Society Clinical Research Professor Award.
Footnotes
See also Galea and Vaughan, p. 783.
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