This article explores the characteristics of research sites that scientists have called "natural experiments" to understand and develop usable distinctions for the social sciences between "Nature’s or Society’s experiments" and "natural experiments." In this analysis, natural experiments emerge as the retro-fitting by social scientists of events that have happened in the social world into the traditional forms of field or randomized trial experiments. By contrast, "Society’s experiments" figure as events in the world that happen in circumstances that are already sufficiently "controlled" to be open for direct analysis without reconstruction work.