What's so bad about misinformation?

Misinformation in various guises has become a significant concern in contemporary society and it has been implicated in several high-impact political events over the past years, including Brexit, the 2016 American elections, and bungled policy responses to the Covid-19 pandemic in some countries. In this paper, I draw on resources from contemporary social epistemology to clarify why and how misinformation is epistemically bad. I argue that its negative effects extend far beyond the obvious ones of duping individuals with false or misleading beliefs. Misinformation has systemic effects on our information environments, making all of us worse off, including the epistemically vigilant. This paper does not offer measures or policies to fight misinformation, but aims to contribute to the prior goal of better understanding what’s bad about misinformation. In doing so, it lays the groundwork for ameliorative projects