Explanations play an important role in our mental lives. In most cases, however, explanations are not deducible outright; multiple explanations exist for any circumstance. Simplicity strongly biases preference. We distinguish between two cases: a preference for a simple underlying reality and a preference for a reality that can be simply described We created a fictional disease scenario with three symptoms; participants rated possible diagnoses. One diagnosis was complex (3 viruses), but had a simple term; the other diagnosis involved 2 viruses. Participants generally favored the simple world over the more complex. Additionally, participants preferred whichever explanation was currently described using fewer terms. About half of participants opted for the simpler label when available, but the simpler explanation when unavailable. It seems that people take into account both the simplicity of the world model postulated by a theory and also the simplicity with which a theory is expressed, when deciding among possible options.