 Physical probabilities are becoming even more crucial to scientific inquiry. Probabilities are not just used to characterize the support given to scientific theories by evidence; they appear essentially in the content of the theories themselves. This has led to fertile philosophical ground interpreting the probabilities in such theories. For example, quantum mechanics has physical probabilities at the fundamental level. The interpretation of these probabilities is related to the interpretation of the theory itself (see the entry on  philosophical issues in quantum theory).  Statistical mechanics and evolutionary theory have non-fundamental objective probabilities. Are they genuine chances? How can we account for them? See Strevens (2003) and Lyon (2011) for discussion. However, Schwarz (2018) argues that these probabilities can and should be left uninterpreted. Loewer (2012) proposes that the Lewisian best system of our world is given by “the Mentaculus”—a complete probability map of the universe. This is Albert’s (2000) package of: