 Book II of Buridan’s treatise presents a sophisticated analysis of the logical behavior of modal sentences. Modal sentences can be either composite or divided, depending on where the modal term occurs: if it is either the subject or the predicate of the sentence, while the other term is an embedded sentence in nominalized form (in ‘dictum’ form, in the medieval terminology), then the sentence is a composite modal sentence. If however the modal term occurs as an adverb modifying the copula, then it is a divided modal sentence. Buridan then proves a series of conclusions and equivalences for each kind of modal sentences, such as that ‘B is necessarily A’ is equivalent to ‘B is not possibly not A’ (Johnston 2014).