In this talk I present a sketch of a new form of Fictionalism regarding abstract objects. My proposal may be summarized as follows: in certain cases, a proposition P is a determinable property of possible worlds and abstract objects are entities fictionally introduced to define a particular class of determinates of P. I start by drawing the distinction between truth-conditional and truth-making world properties. A truth-conditional property is a property that a world has iff it makes true a given sentence (i.e. a proposition); a truth-making property is a property that a world has iff it makes true a given sentence with a defined truth-maker. Every truth-conditional property P has a set of truth-making properties that may be seen as specifiers of P. I argue that a truth-conditional property P is a determinable property having as determinates the set of truth-making properties that specify P. Successively, I show that given a proposition P being a determinable property and being D a class of truth-making properties that determine P, there is a class D' of world properties representing a new level of specification in the hierarchy of determination of P. More precisely, D' is a class of world properties that determine P and each element of D' is determined by a certain class of properties in D. The condition for the existence of D' amounts to the possibility of defining a relation of similarity between worlds: two worlds have the same property in D' iff they have different truth-making properties in D and they makes P true in a similar way. I call D' the intermediate class of determinates of the proposition P. Then I define my version of fictionalism. Strictly speaking, the properties belonging to an intermediate class D' of determinates of a proposition P are not truth-making properties, for there is no entity associated with each property in D' that may be taken as a possible truth-maker for P. However, the properties in D' “perform the same theoretical task” of truth-making properties: they are specifiers of a given proposition. Therefore, it is possible to introduce fictional entities that are fictional truth-makers associated with the class of properties in D'. Such entities are the abstract objects that may be used to represent the truth-conditions of P in an alternative way. Finally, I formulate an interesting condition to decide in which cases the introduction of fictional entities is theoretically fruitful and I briefly present how the proposal may account for the introduction of cardinal numbers as fictional entities.