This work presents a unified theory of social institutions, integrating insights from philosophers and social scientists. Francesco Guala develops a framework that synthesizes three influential perspectives: institutions as equilibria of strategic games, regulative rules, and constitutive rules. He examines fundamental institutions such as money, private property, and marriage, offering a much-needed convergence of equilibrium and rules-based approaches. The theory, while grounded in game theory, is articulated in an accessible style for a diverse scholarly audience. Guala discusses the implications of this unified theory, tackling enduring issues like reflexivity, realism, Verstehen, and fallibilism in social sciences. He critically engages with Ian Hacking's concepts of "looping effects" and "interactive kinds," questioning the possibility of distinguishing between social and natural sciences based on causal and ontological dependence. By focusing on contemporary debates surrounding the definition of marriage, Guala illustrates how abstract philosophical discussions have significant practical and political ramifications. Ultimately, this work transcends specific examples to provide fresh insights into the nature, functioning, and potential of institutions.
