Possible disagreements and defeat

Conciliatory views about disagreement with one’s epistemic peers lead to a somewhat troubling skeptical conclusion: that often, when we know others disagree, we ought to be (perhaps much) less sure of our beliefs than we typically are. One might attempt to extend this skeptical conclusion by arguing that disagreement with merely possible epistemic agents should be epistemically significant to the same degree as disagreement with actual agents, and that, since for any belief we have, it is possible that someone should disagree in the appropriate way, we ought to be much less sure of all of our beliefs than we typically are. In this paper, I identify what I take to be the main motivation for thinking that actual disagreement is epistemically significant and argue that it does not also motivate the epistemic significance of merely possible disagreement.