Roberts v. City of Boston is a well-known legal case in the history of US education. In 1847, the Boston School Committee denied Sarah C. Roberts, a five-year-old African American girl, admission to the public primary school closest to her home. She was instead ordered to attend the all-black Abiel Smith School, about a half-mile walk from her home. In March 1848, Sarah's father, Benjamin, sued the city of Boston for denying Sarah the right to attend the public school closest to her home. The case wound its way through the courts, eventually reaching the Massachusetts Supreme Judicial Court. In 1850, Chief Justice Lemuel Shaw ruled in favor of the city of Boston, affirming that the Boston School Committee had “not violated any principle of equality, inasmuch as they have provided a school with competent instructors for the colored children, where they enjoy equal advantages of instruction with those enjoyed by the white children.” And thus, the doctrine of separate but equal was born in Massachusetts.

In Carl Kaestle's 1992 essay “Standards of Evidence,” generalization is how we know when we know. Kaestle sketches a model of increasing certainty in historical claims as they are developed and refined at increasing scales of research, from local to international. A historical claim might originate in the study of a particular place or case, but to know that the claims were true, the historian needed to move from the microlevel view to a more macro one, perhaps at the national rather than local level. Once tested and refined through comparison with other cases, possibly smoothing some of the rougher edges in the process, the claim could then be transferred beyond national borders. When a historical claim is polished enough to fit other contexts, we know it is true. Kaestle illustrates this increasing certainty through increasing scale with reference to the history of literacy and, more specifically, to scholarship on how Western European and US industrialization shaped literacy rates. Bringing studies from various locales into connection, and then comparing these cases with the national context, Kaestle summarizes that it was the commercial processes of urbanization, rather than industrialization itself, that helped produce rising literacy in the seventeenth, eighteenth, and nineteenth centuries. Generalization at greater scale becomes not only the means through which to claim the value of historical work, but the basis for constructing historical knowledge in the first place.

In 1976, after being imprisoned and forced into exile from his home country, Uruguay, Eduardo Galeano defiantly wrote “Defensa De La Palabra” (In Defense of the Word). In it, he argued that denying people access to their histories obstructs their vision of themselves as a people connected across time, and therefore restricts their ability to envision change for their future. He believed contributions to the revelation of the past depended on “the intensity level of the writer's responsiveness to his or her people—their roots, their vicissitudes, their destiny.” Forty-four years later, Galeano's reflections remain timely and methodologically instructive for those working at the nexus of history and education: