Educators have been increasingly concerned with what can be done about "post-truth" problems--that is, threats to people's abilities to know what is true--such as the spread of misinformation and denial of well-established scientific claims. The articles and commentaries in this special issue present diverse perspectives on how "post-truth" problems related to scientific and socio-scientific issues might be educationally addressed. The goal of this introductory article is to review and analyze the educational responses to the "post-truth" condition that are reflected in this special issue and in the literature at large. We argue that these responses have employed four lenses that focus on different underlying factors related to people's ways of knowing: not knowing how to know, fallible ways of knowing, not caring about truth (enough), and disagreeing about how to know. Each of these lenses offers different explanations of how education might aggravate or mitigate "post-truth" troubles.