After Quetelet calculated the average chest circumference of Scottish soldiers, he concluded that each individual soldier’s chest size represented an instance of naturally occurring “error,” whereas the average chest size represented the size of the “true” soldier—a perfectly formed soldier free from any physical blemishes or disruptions, as nature intended a soldier to be.
Quetelet followed the same line of reasoning with regard to humanity as a whole, claiming that every one of us is a flawed copy of some kind of cosmic template for human beings. Quetelet dubbed this template the “Average Man.” Today, of course, someone described as “average” is implied to be inferior or lacking. But for Quetelet, the Average Man was perfection itself, an ideal that Nature aspired to, free from error. He declared that the greatest men in history were closest to the Average Man of their place and time.
Eager to unmask the secret face of the Average Man, Quetelet began to compute the average of every human attribute he could get data on. He calculated average stature, average weight, and average complexion. He calculated the average age couples got married and the average age people died. He calculated average annual births, average number of people in poverty, average annual incidents of crime, average types of crimes, the average amount of education, and even average annual suicide rates. He invented the Quetelet Index—today known as the body mass index, or BMI—and calculated men’s and women’s average BMIs to identify average health. Each of these average values, claimed Quetelet, represented the hidden qualities of the Average Man.
As much as Quetelet admired the Average Man, he held an equal amount of antipathy toward those unfortunate individuals who deviated from the average. “Everything differing from the Average Man’s proportions and condition, would constitute deformity and disease,” Quetelet asserted. “Everything found dissimilar, not only as regarded proportion or form, but as exceeding the observed limits, would constitute a Monstrosity.” He also pronounced, “If an individual at any given epoch of society possessed all the qualities of the Average Man he would represent all that is great, good, or beautiful.”
Though today an average person isn’t thought to embody perfection, it is presumed that an average person is a prototypical representative of a group—a type. There is a powerful tendency in the human mind to imagine that all members of a group—such as “lawyers,” “the homeless,” or “Mexicans”—act according to a set of shared characteristics, and Quetelet’s research endowed this impulse with a scientific justification that quickly became a cornerstone of the social sciences. Ever since Quetelet introduced the idea of the Average Man, scientists have delineated the characteristics of a seemingly endless number of types, such as “Type-A personalities,” “neurotic types,” “micro-managers,” and “leader types,” arguing that useful predictions could be made about any given individual member of a group simply by knowing the traits of the average member—the group’s type.