How Averages Became Normal

Abstract

Abstract Averages became a distinctive form of information in early modern European culture, first in commercial arithmetic, then in natural philosophy, demography, political economy, and eventually in eclectic social analysis. Averaging, in the modern sense of calculating an arithmetic mean by adding up the individual values of cases in a set and then dividing that total by the number of cases, provided an empirical and heuristic resource for understanding planetary orbits, fertility and mortality rates, experimental results in natural philosophy, fiscal resources, the return on stock market investments, the relative profitability of crops, incomes and the cost of living, and even the trivia of daily life. Averaging created a new class of fact—precisely typifying information that varied. By the Enlightenment, averages had become a respectable, readily deployed, form of fact, giving unity to the variety of experience and knowledge. Averages became a metaphor of credibility and normality.