 According to Hughes (1989), one could supply a Kripke-style possible worlds semantics to Buridan’s modal system. This is done in Johnston 2015. In discussing the conception of simultaneous alternativeness in fourteenth-century logic, many historians have used the terminology of possible worlds semantics without the metaphysical and formal details of the modern theory (Yrjönsuuri 1994, 167–174; Dutilh Novaes 2007, 90–91; Read 2021. Ockham and Buridan state that the truth of ‘A white thing can be black’ demands the truth of ‘This can be black’ and that ‘This can be black’ and ‘‘This is black’ is possible’ mean the same. Compound (de dicto) and divided (de re) readings do not differ at this level, but are separated in dealing with universal and particular propositions. While Ockham did not discuss unrestricted divided necessity propositions, Buridan took the subject terms of all quantified divided modal propositions as standing for possible beings if they are not restricted. The truth of these propositions demands the truth of all or some relevant singular propositions of the type just mentioned; the demonstrative pronoun is then taken to refer to the possible beings even though they may not exist. Buridan could have said that the possible truth of ‘This is X’ means that it is true in a possible state of affairs in which the possible being referred to by ‘this’ occurs and that the necessary truth of ‘This is X’ means that it is true in all possible states of affairs in which the possible being referred to by ‘this’ occurs (Hughes 1989). For Buridan’s modal logic, see also Read’s introduction to Treatise on Consequences (2015); Johnston 2021. 