In this course we will look at the relationship between justification and epistemic duty, with a focus on how these concepts relate to the epistemology of disagreement. The traditional view is that justification involves having reasons and having reasons that one has to access to. On this internalist view, to be justified is to be epistemically blameless. As such, a justified belief is one that can stand up to critical scrutiny (self-imposed or otherwise). We will start off my examining this view as it plays out in the ethics of belief, following which we will turn our attention to the debates in the epistemology of disagreement and spend the rest of the semester figuring out what is at stake there. We will end by exploring the case wherein a person disagrees with herself.