The Average Person: Why “Normal” Is the Main Pathology

Our lives are governed by a system of norms: we know exactly how many hours we should sleep, how much we should weigh, and how much water we should drink each day. Yet our “ideal self,” which fully conforms to all these standards, always seems just out of reach. But what are norms, and is it really healthy to follow them? Jonathan Sholl, a lecturer in medical philosophy at Aarhus University in Denmark, believes that medicine should shift from universal standards to individualized recommendations. “Theories and Practices” presents a translation of his article for Aeon.

The Problem of Variability in Medicine

Medicine struggles with the issue of variability. In the 19th century, French physiologist Claude Bernard argued that individual variability interferes with medical conclusions. He believed that if we could prove that pathology is simply a quantitative deviation from the norm, we would have the key to treating anyone, regardless of how different they are from others. After all, if pathology is just a deviation, then both the goal and the method of therapy become clear: to return the sick person, organ, cell, or system back to a normal state.

This perspective still underpins much biomedical research; scientists regularly intervene in the workings of organisms, cells, and gene networks to determine how these systems function “normally.” Researchers disrupt usual processes in living systems to establish standards and find new treatments.

What Does “Normal” Really Mean?

But what do we mean when we talk about normal physiology? As philosopher Sara Moghadam-Taaheri wrote in 2011, if we view abnormality not as “broken normality” but as a qualitatively different state, it’s hard to see how such interventions can restore a patient’s health.

While researchers may overlook these nuances, medical philosophers have been analyzing and trying to define “normal” for years. One thought experiment asks us to consider traits at the edges of the spectrum that aren’t considered pathologies: green eyes, color blindness, very tall or very short stature, photographic memory, heightened taste. These can be contrasted with other states or variations: those that are problematic only in certain environments (like inability to recover from UV exposure); those that are only problematic in some cultures or at certain times (albinism or auditory hallucinations); and those so extreme that they disrupt normal functioning (like Tay-Sachs disease).

But even with various problems, people can live normal lives. For example, some people with high IQs lead normal social lives despite having hydrocephalus—a condition where excess fluid in the brain’s ventricles expands the skull and often causes serious damage. How can normality be a scientific concept when its spectrum is so broad? Ultimately, what is normality? Do we even understand the word correctly? And how do we conform to norms?

“No matter how unusual an individual seems, they can still be considered normal if their behavior ensures survival in a specific environment.”

The Many Meanings of “Normal”

Czech philosopher Jiří Vacha, in 1978, systematized the different meanings of normality. “Normal” can mean frequent, as in the most common trait in a population, like brown eyes among Mediterraneans or blue among Scandinavians. “Normal” can mean average in the mathematical sense, like average weight or height—often shown as a bell curve on graphs; or typical, as in a representative of a group, population, or species. Sometimes “normal” means conforming—without defects or disorders; sometimes it means optimal, as in peak physical health or sharp intellect. Or it can be interpreted as ideal in the Platonic sense, referring to perfect beauty or a perfect body. Finally, there’s our everyday use of the word, which usually falls somewhere between all these meanings, from “accepted” and “standard” to “expected” and “good.”

In any case, using “norm” in a specific sense can have serious consequences, especially since “normal” holds a privileged position in society. Any deviation—from green eyes and hearing voices to living with hydrocephalus—will be considered abnormal in some context: uncommon, rare, atypical, potentially nonconforming, disadvantageous, or defective in some way—and thus something to be corrected. However, considering such variations as pathologies is debatable or even strange, especially if they are beneficial in some sense.

The Rise of the “Average Person”

This ambiguity has persisted in medicine for centuries. In the 19th century, when Bernard defined disease as “a deviation from the norm,” Belgian mathematician Adolphe Quetelet tried to study the human body statistically to find patterns in individual differences. Since any parameter could be studied this way, it seemed everything could be explained by averages; thus, height, weight, blood pressure, heart rate, birth and death rates—all could be represented as neat curves.

In Quetelet’s mind, these averages took on a life of their own; they were no longer just descriptions but became ideals to strive for. In fact, the now-controversial body mass index (BMI), often used to assess health, was originally called the Quetelet Index.

Quetelet believed these measures described the homme moyen, or “average man”—the ideal person nature could create, standing at the center of what probability theory calls a Gaussian distribution. While such a person need not exist in reality, the mathematical values were seen as the true standard by which deviations—and thus deficiencies—were judged. “Individuality became synonymous with error, and the average person was considered the real person.” Combined with Bernard’s views, this approach paved the way for the privileged status of normality we see today.

Normality as Context-Dependent

In the 20th century, French philosopher Georges Canguilhem offered a more modern view: in pursuing the concept of normality, 19th-century scientists overlooked the evolutionary biology of variability. In his work “The Normal and the Pathological” (1943), Canguilhem describes Darwin’s idea that organisms establish and maintain constancy, patterns, and behaviors to survive changing circumstances. Canguilhem used “norm” to refer to various regulatory processes, from internal hormone regulation to dietary changes, to remind us: no matter how unusual or far from the norm an individual seems, they can still be considered normal if their behavior ensures survival in a specific environment.

In short, the concept of normality depends on context. What’s normal for one may be unacceptable for another; the same organism may be normal in one environment and abnormal in another. Just look at innate differences in lactose processing or acquired differences: for example, endurance athletes have larger hearts and slower pulses. These examples show that normality varies among people and that differences—even anomalies—are not necessarily signs of pathology.

This relativity, dependent on environment, is seen everywhere. Some people with asymptomatic hypertension suffer chest pain, nausea, and shortness of breath at high altitudes. People vary in their ability to recover from UV exposure: from minor skin damage to malignant growths and cancer. Dyslexia, some argue, should only be considered harmful where reading is essential to the culture. Even a particular environment is neither normal nor abnormal. Only the relationship between individual and environment defines the line between normal and abnormal variations.

Normality Is Neither Absolute Nor Universal

Normality can be neither absolute nor universal. At the same time, Canguilhem argued, this doesn’t mean we should abandon the study of health and disease from a biological perspective. We need to look at health and illness, recognizing that within them exist psychological, behavioral, and structural patterns, causal relationships, and biological norms. Canguilhem suggests dividing norms into “driving” and “repelling” types. Driving norms withstand various disturbances and adapt to changing demands, allowing the organism to overcome obstacles. A driving immune response includes producing antibodies to fight hostile bacteria and toxins.

Repelling norms avoid disturbances and limit the organism’s functioning; their fragility requires a strictly defined environment. A repelling immune response to invaders includes inflammation, which can lead to hypersensitivity and extreme allergic reactions, even anaphylactic shock.

Canguilhem’s inductive approach contradicts the conclusions of 19th-century scientists and the very concept of normality as an unchanging quality, still common today. Instead of starting with a rigid definition of normality from which abnormality follows, Canguilhem’s method begins with physiology and then seeks theoretical explanations for what is observed.

This method launched research that medical philosophers now call naturalization. Answers should come from observing qualities like resilience (maintaining constancy despite changes), plasticity (shifting between different levels of function), homeodynamics (compensating for aging), and fragility (increased sensitivity to change). Using these and other indicators, biology—not the idea of normality—defines what is characteristic of health and disease.

“In many cases, changing the environment may be more effective than acting on the patient.”

Medicine for the Individual, Not the Average

A systematic biological approach is also more applicable to a changing world, where species are constantly in motion and organism and environment must be synchronized. After all, systems can be stable, homeostatic, or fragile only under certain external and internal conditions. You can’t talk about the resilience of the immune system, a gene network, or an entire organism without specifying the many biological variables and environmental parameters. Each system is unique and inseparable from its surroundings. This leads us to the question: when we talk about health, health for whom? Relative to which internal and external conditions?

Answers to these questions are critical for understanding health and treating disease. This approach can help eliminate the stigma of illness, since we assume that both health and disease are normal—they reflect different patterns and ways of life. Disease is not contrary to nature and does not signal the absence of norms—the norms are simply different. This doesn’t mean we should glorify illness: we don’t need to see suffering as a virtue or a way to build character, just as we shouldn’t view mental illness as a path to enlightenment. On the contrary, as naturalization suggests, the fact that both health and disease are normal doesn’t mean they are equal or indistinguishable.

Viewing our biology through the lens of naturalization offers a new perspective on healthy habits. While Canguilhem’s philosophy suggests that only the individual can determine what benefits them, this doesn’t mean health is just a matter of subjective choice or that everyone has unlimited power in this regard: for example, I prefer X and you prefer Y, so for me X is a healthy choice. A person’s health is individual because of the influence of their unique life history and behavior on their body and mind. So medicine should determine what is preferable for each person based on their own biology, environment, and lifestyle.

All this suggests that medicine should not try to restore previous norms (which may not exist) after disease or simply time has permanently changed a living system. Nor should it force people to conform to uniform standards and treatments dictated by health authorities, since what helps one person may harm another. Instead, a new, individualized medicine should work with the person to find a new way of functioning that takes into account their unique physiology, as well as the possibilities and limitations of their specific environment. In many cases, changing the environment may be more effective than acting on the patient.

This perspective has never been more critical, given concerns that medical institutions are pathologizing normality—introducing treatments that reflect social and political values rather than the disease itself. Whether it’s the surge in Ritalin use in schools or ever-changing advice on healthy diets, it seems what we need most is a philosophy of medicine that focuses on the patient’s interests and fits the context of each person’s life.