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Primer: Adolphe Quetelet, Statistics, and Social Physics June 4, 2009

Posted by Will Thomas in EWP Primer.
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Adolphe Quetelet (1796-1874)

Adolphe Quetelet (1796-1874)

Throughout the 19th century, the nature of social changes and regularities in social activity remained an intense concern as population growth, urbanization, industrialization, and political upheaval captured the attention of scientific and political thinkers throughout Europe and America.  As today, this thought necessarily spanned political, popular, philosophical, and scientific realms of thought as debates ensued concerning what could be said about societies and what could and should be done to affect how they function.

In the early 19th century, keeping and deploying statistics was already widespread, but their use as a tool of political discourse remained novel, and thus a subject of general and heated discussion.  The astronomer and essayist Adolphe Quetelet proved to be one of the century’s most singular and influential thinkers concerning the use of social statistics.  Born in Belgium in 1796 shortly after French annexed Austria’s Belgian provinces in the wars following the Revolution, Quetelet was educated in a French lycée, and as a youth took notice of the place accorded to the sciences in the Napoleonic empire.  After Napoleon’s fall in 1815, Quetelet taught mathematics in Ghent, earned a doctorate in the subject, and, after convincing the government to build an observatory in Brussels, he departed to Paris—still the intellectual center of the world—to learn astronomy.  Quetelet took up his post as director of the new Brussels Observatory in 1828, and the observatory began operation in 1832.

By no coincidence, it was in this same period that Quetelet first began writing about statistics and “social physics” (a phrase taken from contemporary “positivist” philosopher and social theorist Auguste Comte).  Principles of statistics and probability had been worked out by key figures in the development of the technical methods of astronomy in France who were also interested in social statistics, particularly Pierre-Simon Laplace (1749-1827).  And, like many others writing on social phenomena in the 18th and 19th centuries, Quetelet was struck by the constancy of certain statistics from year to year, such as births, deaths, crimes, and suicides.  Even though the fates of individual humans seemed to be governed by their free will and happenstance, taken en masse they seemed to be governed by social laws, which individual people appeared to be largely helpless to alter.  It therefore made sense to speak of society as an entity possessed of its own independent nature.  In 1848—a year of major political upheaval in Europe—Quetelet observed approvingly in his work On the Social System and the Laws that Govern It that not even revolutionary political change could alter basic social realities such as the frequency of crime.

Quetelet’s approval of the constancy of social relations related to his belief in political and moral moderation as a means of governing them.  Where some thinkers in this period understood history as requiring, doomed to, or inevitably headed toward radical change (as in the thinking of Charles Fourier, Arthur de Gobineau, or the dialectical philosopher Karl Marx), and where some elements of political economy suggested that social conditions were fatalistically inalterable, Quetelet believed that the study of statistical phenomena could reveal a high road toward a society governed by the intellect rather than by gross physical principles.  Essential social change, he believed, had been—and would continue to be—gradual, as society strove progressively toward an increasingly conscious understanding of how to govern its own natural development.  As he wrote in his touchstone 1835 work, On Man and the Development of His Faculties, or an Essay on Social Physics:

The perfectability of the human species is derived as a necessary consequence of all our investigations.  Defects and monstrosities disappear more and more from the body; the frequency and the gravity of maladies are combatted with greater effectiveness through the progress of medical science; the moral qualities of man will meet with improvements no less tangible; and the more we advance, the less need we fear the effects and the consequences of great political upheavals and wars, the plagues of humanity.

Thus, while Quetelet ought to be grouped with those 19th-century thinkers who understood history as proceeding through a general arc, the principles governing the path of this arc exerted their influence piecemeal rather than according to a grand historical logic governing the succession of epochs.  Here Quetelet was deeply influenced by his technical understanding of probability and error theory from his astronomical training, though he rarely used any advanced methods in his statistical analyses of social data.

While astronomers understood objects to move through the universe according to Newton’s laws, these paths were constantly perturbed by the minute gravitational pull of all objects, and observations of paths were imperfect.  To face these challenges, mathematicians had developed advanced means of resolving conflicting observations and of approximating the mathematical functions describing trajectories of celestial objects.  Mathematically, these methods were closely linked to the calculus of probability, which, of course, governed the behavior of large numbers of individually unpredictable phenomena.  The deviation from expected behavior was governed by an omnipresent function that we now know as the Gaussian distribution after Quetelet’s contemporary, German mathematician and physicist Carl Friedrich Gauss (1777-1855).

Quetelet understood the applicability of astronomy’s error theory to statistical variation from a determined mean—Quetelet’s main legacy to mathematical statistics—to represent a profound truth of nature.  If one measured human and social attributes according to a distribution surrounding an average, one would begin to gain an appreciation of the qualities of l’homme moyen, or “the average man”.  In an Aristotelian move, Quetelet felt that the average man represented an ideal of nature, from which perturbing factors would cause reality to deviate.  For example, a human of average height could be taller or shorter according to specific conditions such as diet or climate.  While some progressive thinkers in this era celebrated individuality and variation, for Quetelet using statistics to inquire into the physical and moral qualities of the average man represented a path to understanding social laws, which was the path of further enlightenment, good morals and governance, and, ultimately, the harmonious society.

As near as I can tell there is no extensive treatment of Quetelet’s life written in the last hundred years, but his work and thinking are discussed in overviews of the history of statistics and probability and their politics.  See especially Ted Porter’s The Rise of Statistical Thinking, 1820-1900 (1986), from which this post draws heavily


1. De Quetelet and the origin of statistical and population thinking « Evolving Thoughts - June 4, 2009

[…] sizes were constantly distributed in different samples. Will Thomas at Ether Wave Propaganda has a good piece on […]

2. Padraic - June 6, 2009

Great post Will. I happen to be in the process of writing what I hope will be the first published extensive treatment of Quetelet in 100 years.

Overall I think you captured things well, but I would offer one quibble. While Comte did complain that Quetelet had adopted “Social Physics” (which resulted in Comte adopting his alternative choice – Sociology), there is no evidence Quetelet had read Comte and could have “taken” the name from the Frenchman.

Given that Condocet had come up with Social Mathematics a generation earlier, and the reigning metaphor of the natural sciences, it’s likely that many thinkers independently came up with “social physics.”

3. Will Thomas - June 7, 2009

Thanks for the comment, Padraic. I look forward to seeing the book! I was actually wondering about the Comte thing, since “physics” was so frequently used then to describe the principles governing any systematic set of phenomena, so I’m interested to hear that there was no direct connection.

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