Necessary conditions are everywhere. They have always been there, and they will always be there. Although the formal logic of necessary condition goes back to at least David Hume’s philosophy of science (1777) or even Aristotle, the necessity logic has been largely ignored in modern social sciences. Since Francis Galton’s (1886) discovery of correlation, the focus has been on OLS regression and the General Linear Model and related models (with variants like multiple regression modeling and structural equation modeling). Consequently the current focus of social science research is on sufficient causes.

Because of the enormous practical and theoretical relevance of necessary conditions, and the need for combining rigor and relevance in the social sciences, we expect a revival of attention for necessary conditions in academic social science research. It took sufficiency logic more than 100 years to become well-established. Building on this knowledge and with the currently available computer power, the growing NCA community will rapidly reach a similar level of understanding for necessity logic.