Contemporary society is experiencing an epistemic crisis, evidenced by such "post-truth" phenomena as "alternative facts." Traditional notions related to knowledge and Truth have been under continual, partly justifiable, attack under the eclectic banner of postmodernism, and alternative epistemic foundations (essential for democracy to function) have not been provided. Drawing on the European and North American literature of political theory, philosophy, and adult education, this article offers an update and defense of three core epistemic concepts: rationality, autonomy, and pluralism. To address the epistemic crisis, adult education needs to develop epistemically responsible learners, promote diverse public learning spaces (agoras), and teach learners how to engage in meaningful dialogue outside of their own echo chambers.