 Propositional logic and probability are very different formalisms  (Haenni, Romeijn, Wheeler, &amp; Williamson 2011). For one thing, the truth-functional semantics of logic is compositional whereas probability is not compositional, except when events are probabilistically independent. Why then is the elimination rule from logic and the introduction rule from probability the standard rather than the elimination rule from probability (i.e., marginalization) and the introduction rule from logic (i.e., adjunction)? Answering this question requires a positive account of what “based on”, “anchored in”, or other metaphorical relationships amount to. But, in appeals to principles of reasoning, typically there is no analog to the representation theorems of expected utility theory   (section 1.1)  specifying the relationship between qualitative judgments and their logical or numerical representation, and no account of the conditions under which such relationships hold.