Science's role in society is being threatened, as misinterpretation and denial of scientific evidence and the rejection or ignorance of scientific expertise are gaining prominence. This endangered role of science in society is characteristic of post-truthism. To deconstruct this process, we analyze how three potential gateways allow people to discount the epistemic authority of science. These gateways are (A) the intricacies between values and evidence in science, (B) the intricacies that follow from the social nature and distribution of scientific knowledge, and (C) those that follow from the limits of science. We also outline how this gateway analysis can inform education on scientific literacy in order to protect against post-truthism. Educational measures should highlight the social and conversational nature of scientific knowledge production, because these concepts lay the foundation for learners' and citizens' abilities to build an informed trust in science and, in turn, actively engage in a science-based society.