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Adolphe Quetelet (1796-1874)

Adolphe Quetelet was the first scientist to apply statistical methods to humans in a systematic way. Quetelet had studied astronomy and mathematics in France, and learned how French astronomers used probability to make their measurements of star positions more accurate. He reasoned that it should also be possible to apply these techniques to the measurement of human features and so created a new scientific discipline, which he called ‘social mechanics’.

He created the concept of the ‘average man’, who would exhibit the average features of all individuals. Quetelet used these methods to define what should count as normal physical and mental features, believing that comparing the features of individuals against this ‘average man’ would allow scientists to detect the underlying mechanisms which determine normal and abnormal features.

In 1835 Quetelet published a description of his new science under the title A treatise on man and the development of his faculties. The body mass index, which classifies people's weight as normal or abnormal, has its roots in Quetelet’s work.

Related Themes and Topics



E H Ackerknecht, 'Villermé and Quetelet', The Bulletin of the History of Medicine, 26 (1952), pp 317-329

B P Cooper and M S Murphy, 'The death of the author at the birth of social science: the cases of Harriet Martineau and Adolphe Quetelet', Studies in History and Philosophy of Science, 31A/1 (2000), pp 1-36

T M Porter, 'The mathematics of society: variation and error in Quetelet's statistics', British Journal for the History of Science, 18/1/ 58 (1985), pp 51-69

A Quetelet, A Treatise on Man and the Development of his Faculties (Edinburgh: W and R Chambers, 1842) [available online]



The Body Mass Index (BMI) is a way of working out if a person is over or under weight. It is calculated by dividing weight in kilograms by height in metres. The resulting number is then divided by height in metres again. Currently it is suggested that a healthy BMI lies between 18.5 and 25.