The alleged emergence of a ‘post-truth’ regime links the rise of new forms of social media and the reemergence of political populism. Post-truth has theoretical roots in the interdisciplinary field of Science and Technology Studies, with sociologists of science arguing that both true and false claims should be explained by the same kinds of social causes. Most STS theorists have sought to deflect blame for post-truth, while at the same time enacting a normative turn, looking to deconstruct truth claims and (...) subject expertise to criticism. Steve Fuller has developed a positive case for post-truth in science, arguing that post-truth democratizes science. I criticize this argument and suggest an alternative approach that draws on the prehistory of the field in the 1930s and 1940s, when philosophers and sociologists sought to define the social conditions necessary for reliable knowledge production that might stem mass media irrationalism. (shrink)