Background

Ethnicity: Quetelet's father was a Frenchman and his mother was a Flemish woman.

Lambert Adolphe Jacques Quetelet was born in Ghent on February 22, 1796, the son of François-Augustin-Jacques-Henri Quetelet and Anne Françoise Vandervelde.

Education

Adolphe studied at the Ghent lycée, where he started teaching mathematics in 1815 at the age of 19. In 1819 he moved to the Athenaeum in Brussels and in the same year he completed his dissertation. Quetelet received a doctorate in mathematics in 1819 from the University of Ghent.

Career

In 1819 Quetelet was appointed a professor of mathematics at the athenaeum of Brussels; in 1828 he became a lecturer at the newly created museum of science and literature, and he continued to hold that post until the museum was absorbed in the free university in 1834. In 1828 he was appointed a director of the new royal observatory which it had been decided to found, chiefly at his instigation. The building was finished in 1832, and the instruments were ready for work in 1835, from which date the observations were published in 4 volumes, but Quetelet chiefly devoted himself to meteorology and statistics.

From 1834 he was perpetual secretary of the Brussels Academy, and published a vast number of articles in its Bulletin, as also in his journal, Correspondence mathématique et physique (1825-39). He died at Brussels on the 17th of February 1874. His son, Ernest Quetelet (1825-78), was from 1856 attached to the observatory, and on his death succeeded him as director. He made a great number of observations of stars with proper motion.

Quetelet's astronomical papers refer chiefly to shooting stars and similar phenomena. He organized extensive magnetical and meteorological observations, and in 1839 he started regular observations of the periodical phenomena of vegetation, especially the flowering of plants. The results are given in various memoirs published by the Brussels Academy and in his works Sur le climat de la Belgique and Sur la physique du globe (the latter forms vol. xiii. of the Annales, 1861). He is, however, chiefly known by the statistical investigations which occupied him from 1823 onward.

In 1835 he published his principal work, Sur l'hornme et le développement de ses facultés, on essai de physique sociale (1869), containing a résumé of his statistical researches on the development of the physical and intellectual qualities of man, and on the “ average man both physically and intellectually considered.

In 1846 he brought out his Lettres d S. A. R. le due régnant de Saxe-Coburg et Gotha sur la théorie des probabilités applique aux sciences morales et politiques (of which Sir J. Herschel wrote a full account in the Edinburgh Review), and in 1848 Du systéme social et des lois qui le régissent. In these works he shows how the numbers representing the individual qualities of man are grouped round the numbers referring to the “average man " in a manner exactly corresponding to that in which single results of observation are grouped around the mean result, so that the principles of the theory of probabilities may be applied to statistical researches on the subjects.

These ideas are further developed in various papers in the Bulletin and in his L'lnthropométrie, on mesure des diférentes facultés de l'homme (1871), in which he lays great stress on the universal applicability of the binomial law, according to which the number of cases in which, for instance, a certain height occurs among a large number of individuals is represented by an ordinate of a curve the binomial) symmetrically situated with regard to the ordinate representing the mean result (average height).

Achievements

• 

  Lambert Adolphe Jacques Quételet is considered the founder of modern statistics and demography. He also made a great number of observations of stars with proper motion. Quetelet also proposed a simple measure for classifying people's weight against the ideal weight for their height, which is known today as the body mass index (BMI).
  
  Another Quételet's achievement was in becoming a moving force behind the establishment of the Brussels Observatory in 1828, which he was a head of for the rest of his life. He was influential in introducing statistical methods to the social sciences. He developed the body mass index scale. His work was heralded as an important contribution to analytic geometry.
  
  In 1885, he was the first to demonstrate that the "average man" was the central value (the mean) of measured variables (such as height or weight) that followed a normal distribution (a range of values that produce a bell-shaped curve on a graph).
  
  The asteroid 1239 Queteleta is named after him. The title of Quetelet professor at Columbia University is awarded in his name.

Works

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• book

  • Sciences mathématiques et physiques au commencement du XIXe siècle

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    1867
  • Histoire Des Sciences Math Matiques Et Physiques Chez Les Belges 1864
  • Popular Instructions on the Calculation of Probabilities: To Which Are Appended Notes by Richard Beamish 1839
  • A Treatise on Man and the Development of his Faculties 1842
  • Relation D'un Voyage Fait À La Grotte De Han Au Mois D'août 1823
  • Recherches sur la Population, les Naissances, les Décès, les Prisons, les Dépôts de Mendicité, Etc: Dans le Royaume des Pays-Bas 1827
  • Recherches Statistiques Sur Le Royaume Des Pays-Bas 1829
  • Astronomie Elementaire 1892
  • Sur l'Homme Et Le Développement de Ses Facultés, Ou, Essai de Physique Sociale 1835
  • De l'influence des saisons sur la mortalité aux différens âges dans la Belgique 1838
  • A Treatise On Man and the Development of His Faculties 1842
  • Sur l'emploi de la boussole dans les mines 1843
  • Sur Le Climat De La Belgique 1851
  • Du Système Social Et Des Lois Que Le Régissent 1848
  • Mémoire Sur Les Lois Des Naissances Et de la Mortalité À Bruxelles 1850
  • Mémoire sur les variations périodiques et non périodiques de la température : d'après les observations faites, pendant vingt ans, à l'observatoire royal de Bruxelles 1853
  • Sur La Physique Du Globe 1861
  • Anthropométrie, Ou, Mesure Des Différentes Facultés De L'homme 1870

Views

Quételet believed that statistical theory and research could be used to determine whether human actions occur with the expected regularity. If so, it would indicate that there are social laws which are as knowable as are the laws which govern the movements of the heavenly bodies. He thought that there were such social laws. He thus developed his famous notion of the "average man." Quételet's concept of the average man was intended to be a construct of the mind or a model which would enable social "scientists" to express the differences among individuals in terms of their departure from the norm.

This theory led to his "theory of oscillation." According to this hypothesis, as social contacts increase and racial groups intermarry, differences between men will decrease in intensity through a process of social and cultural oscillation, resulting in an ever-increasing balance and, eventually, international equilibrium and world peace. Thus, as Quételet saw it, the task of the academic and scientific communities in the immediate future was to develop new social science, based on empirical observation and the use of statistics.

This new science of "social physics" would discover the laws of society upon which human happiness depends. Quételet's subsequent works represent an attempt to formulate this new field of social physics. To accomplish this goal, it was necessary to refine the techniques used in the collection of statistical data, since Quételet believed that through the analysis of such data empirical regularities or laws could be discovered.

His application of quantitative methods and mathematical techniques has been judged as anticipatory of the guiding principle of contemporary social science, especially his efforts to change statistics from a mere clerical function into an exact science of observation, measurement, and comparison of results.

Membership

Adolphe Quetelet became a member of the Royal Academy in 1820. In 1825 he became correspondent of the Royal Institute of the Netherlands, in 1827 he became a member. Quetelet was elected a Foreign Member of the Royal Society in 1839. From 1841 to 1851 he was supernumerary' associate in the Institute, and when it became Royal Netherlands Academy of Arts and Sciences he became a foreign member. In 1850, he was elected a foreign member of the Royal Swedish Academy of Sciences.

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  Royal Society , United Kingdom

  1839 - 1874

Personality

By his contemporaries, Quetelet's personality has been described as charming, enthusiastic, and gifted with wide intellectual interests. Here is what his contemporaries said about him: "Modest and generous, convinced but respectful of others' opinions, always calm and considerate, a man of broad learning and an attractive conversationalist, he won and kept friends wherever he went. A man of excellent tact, as well as tremendous enthusiasm... A man of wide intellectual interests, and at the same time endowed with a prodigious capacity for labor... always animated and genial, found of wit and laughter."

Interests

• Philosophers & Thinkers

  Pierre-Simon Laplace, Joseph Fourier

Connections

In 1825, Lambert Adolphe Jacques Quetelet married Cécile-Virginie Curtet.

Father:

François-Augustin-Jacques-Henri Quetelet

Mother:

Anne Françoise Vandervelde

Son:

Ernest Quetelet

1825 - 1878, he was from 1856 attached to the observatory, and on the death of his father succeeded him as director.

Wife:

Cécile-Virginie Curtet

associate:

Pierre-Francois Verhulst

Quetelet's student Pierre François Verhulst developed the logistic function in the 1830s as a model of population growth.

References

• Dictionary of Scientific Biography
  1975
• Adolphe Quetelet, Social Physics and the Average Men of Science, 1796-1874
  2015
• The Taming of Chance
  1990
• The Politics of Large Numbers: A History of Statistical Reasoning
  2002
• Statistics on the Table: The History of Statistical Concepts and Methods
  1999
• Critical Mass: How One Thing Leads to Another
  2006