Scarcity, Biology, and the Rational Actor

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Book Chapter

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In the late nineteenth century two powerful and very different ideas changed the course of American legal thought. First was Darwin’s theory of natural selection, which quickly migrated from biological evolution to theories about the evolution of norms. The evolved theories took the forms of Social Darwinism and Reform Darwinism.The second idea was marginalist rational actor assumptions that undermined classical political economy by making economics’ theory of value more forward looking and, eventually, more individualistic. Although both movements were driven by an assumption of resource scarcity, they approached the problem in mutually inconsistent ways that few people other than legal scholars were able to harmonize.


Darwin, Social Darwinism, Reform Darwinism, marginalism, rational actor

Publication Title

The Opening of American Law: Neoclassical Legal Thought, 1870-1970