“Science, not Silence”, this is what over one million people demanded when they protested in over 600 cities worldwide on April 22th 2017. Initiated in the United States, scientists and associates set out in an era of perceived post-facticity to defend evidence-based facts against post-truth politics. However, what is the origin of such a March for Science, what idea of science did it represent and what is it, if anything, it forecloses? Referring to Michel Foucault, I intend to follow up these questions by (1) reconstructing the first month of the movement, (2) analysing its inner claim of a singular (search for) truth as well as (3) questioning this claim, focussing on an adverse category in their desired era of facticity: the affective.