A research community must share assumptions, such as about accepted knowledge, appropriate research practices, and good evidence. However, community members also hold some divergent assumptions, which they—and we, as analysts of science—tend to overlook. Communities with different assumed values, knowledge, and goals must negotiate to achieve compromises that make their conflicting goals complementary. This negotiation guards against the extremes of each group’s desired outcomes, which, if achieved, would make other groups’ goals impossible. I argue that this diversity, as a form (...) of value pluralism, regularly influences scientific practice and can make scientific evidence and knowledge more useful and more reliable. As an example, I examine vertebrate paleontology laboratories, which house a variety of workers with different training and priorities, particularly about the meaning of time. Specifically, scientists want to study fully prepared fossils immediately, conservators want to preserve fossils for future use, and preparators mediate between the other groups’ conflicting goals. After all, one cannot study a fossil encased in rock, and one cannot remove that rock without removing information from that specimen. In response, these coworkers articulate their assumptions in everyday deliberations about how scientific evidence should be made and used. I argue that this exchange of assumptions is crucial for a research community to achieve mutually beneficial compromises that benefit current and future knowledge construction. (shrink)