Abstract

Optical media were instrumental in transforming the conception of facts, objectivity, and the »real.« This paper considers their role in structuring understandings of counterfactuals and states that could not be real. By returning to Ernst Mach’s photographic ballistics experiments, writing on thought experiments (a term he coined), and his dispute with Max Planck about the nature of the Weltbild, the article shows that, despite his legacy as a positivist, Mach’s epistemology of mechanical images opened a legitimate space of indeterminacy, contingency, and counterfactuality.