Argument Herbert Mehrtens‘ work and the implications of the historical ideas he advanced went beyond the history of any single discipline. The article therefore addresses three broad issues: (1) Mehrtens‘ reconceptualization of mathematical modernism, in his field-changing book Moderne—Sprache—Mathematik (1990) and other works, as an epistemic and cultural phenomenon in a way that could potentially reach across and also beyond the sciences and also link scientific and cultural modernisms; (2) the extension of his work to the history of modernity itself (...) via the concept of “technocratic modernism”; (3) his seminal contributions to the historiography of the sciences and technology during the National Socialist period, focusing on his critique of claims that mathematics, the natural sciences and technology were morally or politically “neutral” during or after the Nazi era, and on his counter-claim that mathematicians and other scientists had in fact mobilized themselves and their knowledge in support of Nazism’s central political projects. Taken as a guide for understanding science-politics relations in general, Mehrtens‘ work was and remains a counterweight to the political abstinence adopted by many who have followed the “cultural turn” in history of science and technology. In the broadest sense, the article is a plea for the culturally relevant and politically engaged historiography of the sciences and humanities that Mehrtens himself pursued. (shrink)