Opponents of programs for racial, ethnic, or gender diversity often argue that while these policies are misguided, an appropriate sort of diversity is viewpoint diversity, also known as intellectual diversity. What is this idea, and should it be supported? In one sense, it might refer to breadth of coverage. For example, a philosophy department that offers no ethics or political philosophy would be well-advised, when making its next appointment, to prefer candidates who can cover this area. If doing so is understood as enhancing intellectual diversity, few would doubt that the policy is reasonable.  Most defenders of position diversity, however, have a more controversial policy in mind. They urge the appointment of faculty who hold certain opinions. For instance, if all the current members of a department are atheists or agnostics, position diversity calls for the next appointment to be a theist. Similarly, if all are political liberals, then preference should be given to appointing a political conservative. This proposal has serious deficiencies. First, the assumption appears to be that professors defend particular claims and …