Muller v. Oregon (1906) is widely considered the earliest instance in which the Supreme Court used social science research to support its conclusions. In upholding the constitutionality of legislation that limited the number of hours women could work, the Court drew extensively from Louis Brandeis 's brief, which reviewed social science and medical research to argue that long working hours had a negative effect on women's health. The Court's use of the arguments in the Brandeis brief marked an important turning point between 19th century and 20th century legal thought.

The dominant understanding of the law during the 19th century was that the law was a set of formal, neutral, and apolitical rules to be applied deductively to the issues in particular cases. Often described as ...