  Given these problems, the role and importance of Jevons' system of logic and philosophy of mathematics seems to be small. It appears to be limited to a pedagogical aspect: Jevons' writings on logic, such as his Elementary Lessons in Logic, were widely used as textbooks and saw numerous reprints, up to decades after his death. This appraisal would not, however, do justice to Jevons' most important achievement: the introduction of statistics and econometrics in the social sciences and the use of empirical data.