This talk focuses on the devaluation of casuistic argumentation not only among legal minds but also among ordinary litigants in the eighteenth-century Spanish American colonies. It is particularly concerned with how experiments with new ways of thinking about legal logic linked temporal and economic ideas. Enslaved and native litigants began to advance a fundamentally capitalist logic of legal argumentation in the late 1700s. In civil suits aired in royal courts against superiors, unlettered litigants from unlikely places such as Trujillo, Peru and Southern Mexico played with new notions of time, value and law – concepts that are conventionally thought to be the provenance of European intellectuals, especially German philosophers. Their allusions to legal truth and value in the civil cases they brought against masters and community leaders departed from the casuistic mode of legal epistemology inherited from the pan-European civil law tradition, veering into a new way of legal way thinking about time that contained kernels of capitalist logic, especially concepts of speculation and type.