This Article rests on the macrosociological thesis that (i) the concepts and doctrines used in law are determined by the properties of society and that (ii) these properties are produced by large-scale forces. The thesis thus maintains that the content of law is not shaped by the persons who serve as legislators, judges, and executive-branch policymakers; such individuals are merely the vehicles by which societal conditions mold law. To illustrate, the Article examines shifts in law in the United States on a number of subjects, including law setting the age of majority and law regulating access to abortion, and it links these shifts to changes in specific aspects of U.S. society. Data from the 1960 census on the forty-eight coterminous states are analyzed with logistic regression to identify system level properties distinguishing states that liberalized their law on abortion between 1967 and 1972 (i.e., before Roe v. Wade) from states that did not. The regression analysis, in conjunction with time-series data for the nation as a whole, suggests that the liberalization by states and by Roe of law imposed restrictions on abortion was associated mainly with increases in school enrollment and educational level among young women. This Article advances the premise that long-term growth in the quantity of knowledge broadly affected the American social system and its law, and ascribes the rising prevalence and longer duration of education among women—as antecedents of the liberalization of law on abortion—primarily to the expansion of knowledge.