We are said to be living in a “post-truth” condition, in which “vibes” and “alternative facts” matter more than expertise and evidence. According to this view, modern media companies competing for scarce attention, and governments seeking to advance policy agendas and consolidate power, try to shape the understanding of events by leveraging the emotions and confirming the biased convictions of their target audiences—often distorting or ignoring inconvenient truths in the process. How, under such conditions, can the intellectual independence of citizens, and shared understandings of social problems, be fostered? This course addresses that question, focusing especially on the role that the design disciplines might play in countering disinformation, understood as the intentionally misleading presentation of ideas. Readings draw from classic discussions of political propaganda, modern social-scientific explanations of human beings’ susceptibility to deceptive claims about the world, philosophical analyses of the key concepts (such as knowledge, truth and reality) underpinning the phenomenon of disinformation, and current design theory that explores and responds to the implications of the scientific and philosophical literature. A final project invites students to propose a design intervention addressing the contemporary post-truth condition in some constructive way, for example by bolstering individuals’ critical capacities, nurturing social trust, or disrupting disinformation strategies.