The Evolutionary Game Theoretic Foundations of Law

16 Pages Posted: 8 Feb 2016 Last revised: 22 Jun 2016

See all articles by Robin Bradley Kar

Robin Bradley Kar

University of Illinois College of Law

Date Written: February 7, 2016


Interdisciplinary work in the law often starts and stops with the social sciences. To produce a complete understanding of how law works, however, evolutionary game theoretic insights must supplement philosophical, psychological, economic and other social scientific methods.

To illustrate, I discuss two recent contributions to contemporary understandings of how law works. I discuss "The Force of Law" by Frederick Schauer and "The Expressive Powers of Law" by Richard McAdams. Without relying on evolutionary game theoretic resources, Schauer clarifies the need for a philosophically respectable and empirically well grounded account of the ubiquity of legal sanctions. McAdams highlights law's potential to alter human behavior through expressions that coordinate. Still, these contributions generate further puzzles, which -- I argue -- are best resolved using evolutionary game theoretic resources.

Drawing on these resources, I argue -- against Schauer -- that legal sanctions are ubiquitous to law not because they are generally needed to motivate legal compliance but rather because they provide the general evolutionary stability conditions for intrinsic legal motivation. In reaction to McAdams, I argue that law's expressive powers can only function to coordinate human behavior because humans are naturally and culturally evolved to share a prior background agreement in forms of life. Drawing on evolutionary game theoretic resources, I offer a unified framework from within which to understand the complex interrelationships between legal sanctions, intrinsic legal motivation and law's coordinating power. I also highlight several underappreciated aspects of law's psychological underpinnings.

Going forward, interdisciplinary studies of how law works must include greater syntheses of contemporary insights from evolutionary game theory.

Note: This article was written as part of a contribution to a symposium on How Law Works: Interdisciplinary Perspectives.

Keywords: Schauer, McAdams, expressive theory, sanctions, jurisprudence, Hart, internal point of view, evolution, game theory, evolutionary game theory, analytic jurisprudence, sanctions, coercion, coordination, psychology, moral psychology, obligata, nature of law, behavioral economics

Suggested Citation

Kar, Robin Bradley, The Evolutionary Game Theoretic Foundations of Law (February 7, 2016). Law and Social Inquiry, 2016, Available at SSRN:

Robin Bradley Kar (Contact Author)

University of Illinois College of Law ( email )

504 E. Pennsylvania Avenue
Champaign, IL 61820
United States


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