Counterfactuals and Hypothesis Testing in Political Science

TLDR

Scholars in comparative politics routinely assess causal hypotheses by invoking counterfactual cases, yet the methodological soundness of this common practice remains uncertain. The study investigates whether counterfactual reasoning aligns with traditional hypothesis‑testing methods such as regression or Mill’s Method of Difference, and whether it can validly evaluate national and international outcomes. By analyzing case studies on World War I, the non‑occurrence of World War III, social revolutions, Latin American democratic breakdowns, and European fascism, the paper illustrates the use, challenges, and potential of counterfactual argument in small‑N political science research. The paper thoroughly addresses the first question and initiates discussion of the second, suggesting that counterfactuals may be useful but also highlighting methodological concerns.

Abstract

Scholars in comparative politics and international relations routinely evaluate causal hypotheses by referring to counterfactual cases where a hypothesized causal factor is supposed to have been absent. The methodological status and the viability of this very common procedure are unclear and are worth examining. How does the strategy of counterfactual argument relate, if at all, to methods of hypothesis testing based on the comparison of actual cases, such as regression analysis or Mill's Method of Difference? Are counterfactual thought experiments a viable means of assessing hypotheses about national and international outcomes, or are they methodologically invalid in principle? The paper addresses the first question in some detail and begins discussion of the second. Examples from work on the causes of World War I, the nonoccurrence of World War III, social revolutions, the breakdown of democratic regimes in Latin America, and the origins of fascism and corporatism in Europe illustrate the use, problems and potential of counterfactual argument in small-N-oriented political science research.