The phenomenon of conspiracy theories has been a fixture across the world media, and in academic journals, particularly in the era of Covid 19 vaccinations. We read about the psychological bases of their popularity; of the harmful influence of social media; they are analyzed through communication science, and even evolutionary theory. Whether it’s intentional or not, these approaches often end up naturalizing the phenomenon of conspiracy theories, i.e., making them seem as a natural consequence of human nature and of a psyche thrust into the distrustful world of free-flowing information. But why make such an explanatory leap? What if there is a historical, material cause to the popularity of conspiracy theories, if it is actually a contingent fact caused by some particular social conditions? This lecture is about one such potentially crucial historical cause: how the conspiratorial fight against science in the twentieth century was devised, born and financed in the very heart of the liberal order in the USA.