Pluralistic ignorance
In social psychology, pluralistic ignorance is a situation in which a majority of group members privately reject a norm, but go along with it because they incorrectly assume that most others accept it. This is also described as "no one believes, but everyone thinks that everyone believes". In short, pluralistic ignorance is a bias about a social group, held by the members of that social group.
Pluralism (philosophy)
In epistemology, pluralism is the position that there is not one consistent means of approaching truths about the world, but rather many. Often this is associated with pragmatism, or conceptual, contextual, or cultural relativism. In the philosophy of science it may refer to the acceptance of co-existing scientific paradigms which though accurately describing their relevant domains are nonetheless incommensurable.