  Thus according to my usage in this entry, acceptance of the existence of properties, propositions, possible worlds and numbers is compatible with being a nominalist. What is required of nominalists who accept the existence of numbers, properties, possible worlds and propositions is that they think of them as particulars or concrete objects.[2] And rejecting properties, propositions, possible worlds, numbers, and any other items is not sufficient for being a Nominalist about them: to be a Nominalist one must reject them on account of their being universal or abstract objects.