When were mathematical methods first used in sociology? What role did Émile Durkheim play?
The use of statistics in sociology unquestionably dates back to Émile Durkheim's 1897 study of suicide, published that same year by Félix Alcan. Durkheim had studied under Fustel de Coulanges, who had what might be called "pre-sociological training." He was influenced by Auguste Comte. At the École normale supérieure, Durkheim shared a room with Jean Jaurès, known both for his political activism and for editing the Histoire socialiste de la Révolution française (Jules Rouff et Compagnie, 1904). Socialist ideas and interpretations of Karl Marx's work were also spreading at the time.
In his study of suicide, he refuted common-sense assumptions using numerical data and statistical tables. This was a crucial experiment: Durkheim showed that this quintessentially individual act, seemingly a matter of psychology alone, follows social patterns. He made comparisons to test the effect of the variable he was studying. With no comparative tests available, he had to assess the differences between the cells in the tables. In Les Règles de la méthode sociologique (Revue philosophique, 1895), he would make comparison the defining method of sociology.