  Compared to many other topics treated in this encyclopedia, the epistemology of disagreement is a mere infant. While the discussion of disagreement isn’t altogether absent from the history of philosophy, philosophers didn’t start, as a group, thinking about the topic in a rigorous and detailed way until the 21st century. For that reason, it is difficult to know what the primary issues and questions are concerning the general topic. At this early stage of investigation we are just getting our feet wet. In this essay, we begin by trying to motivate what we think should be the primary issues and questions before we move on to look at some of the main ideas in the literature. In so doing we also introduce some new terminology and make some novel distinctions that we think are helpful in navigating this relatively recent debate.