  For Stalnaker possible worlds are ways the world might have been and such ways are properties (2003, 7). All these ways the world might have been actually exist but only one of them is instantiated — the way the world actually is. He naturally takes these properties to be abstract objects (2003,   32).[22]  A view like this has been further developed by Peter Forrest, who proposes certain properties that he calls natures (certain conjunctions of natural non-relational properties) to play the role played by possible worlds. These natures are, for the most part, uninstantiated properties (1986a, 15). It is natural to think that they are abstract   objects.[23] 