Insofar as possibilia are said to exist in non-actual possible worlds, those worlds are themselves a variety of merely possible, non-existent objects

To appreciate Plantinga’s account, note first that a challenge to actualism that we have not focused on hitherto is the nature of possible worlds themselves. The main reason for this is simply that the basic semantic argument for possibilia laid out in the Introduction to this entry does not assume or require them. If, however, one takes possible world semantics of some ilk seriously, so that possibility and necessity are correlated in some manner with truth at some or all possible worlds, the