 John Duns Scotus developed the model of modality as alternativeness into a detailed theory. A logical possibility is something to which to be is not repugnant, though it may not be compossible with other possibilities. Scotus’s modal semantics influenced early fourteenth-century philosophy and theology in many ways. Thirteenth-century essentialist assumptions were dropped from modal syllogistic, the Aristotelian version of which was regarded as a fragmentary theory without a sufficient explication of the various fine structures of modal propositions. While the Aristotelian frequency interpretation of modality was not found relevant in late medieval logic, it continued to play a role in natural philosophy.