Since its initial proposal, epistemologists have suggested various theories for how the problem of peer disagreement might be resolved, followed by numerous critical and supporting assessments of these proposals. Little attention, however, has been paid to the other side of this issue. In this dissertation, I propose there is an apparent inverse symmetry of sorts between the problem of disagreement and the flip-side of that issue, which I call the assurance of agreement. I argue that a unified theory is needed to deal with both the disagreement and agreement sides of the overarching picture. This theory should not merely address the question of disagreement and agreement between peers but should also extend to inferiors and superiors as well. Such a theory should also include a means for updating one’s confidence in such cases. In contribution to this effort, I propose a model for belief updating that is agnostic to the underlying view and is suitable for cases of agreement (or disagreement). I show how the proposed model can be expanded for use in cases of agreement involving peers, inferiors, and superiors. I then expand this discussion to show how the model can also be used in cases of consensus, which leads to the development of a consensus gentium argument for the reasonable belief in the existence of God. In chapter 1, I make a case for the need for a unified theory, and I propose a theory-agnostic model for updating in cases of agreement and disagreement. In chapter 2, I make a case for updating based on the agreement of superiors and inferiors and show how the model can be adjusted for these cases. Finally, in chapter 3, I set the stage for a consensus gentium argument and develop the argument using a modified version of the previously developed model.