This chapter formulates a rational uniqueness principle holding that those who are epistemic peers on a proposition, in that they know that they share all rational considerations concerning the truth of the proposition, cannot be justified in having different attitudes toward it. It then argues against the principle, primarily on the grounds that such peers may rationally regard themselves as differing in their basis for rational belief, or their evidence, on the topic. The rationality of their differing perspectives can justify (...) having different attitudes toward the disputed proposition. (shrink)