 Church (1956: 25), when considering truth values, explicitly attributes to them the property of being abstract. Since then it is customary to label truth values as abstract objects, thus allocating them into the same category of entities as mathematical objects (numbers, classes, geometrical figures) and propositions. One may pose here an interesting question about the correlation between Fregean logical objects and abstract objects in the modern sense (see the entry on  abstract objects).   Obviously, the universe of abstract objects is much broader than the universe of logical objects as Frege conceives them. The latter are construed as constituting an ontological foundation for logic, and hence for mathematics (pursuant to Frege’s logicist program). Generally, the class of abstracta includes a wide diversity of platonic universals (such as redness, youngness, justice or triangularity) and not only those of them which are logically necessary. Nevertheless, it may safely be said that logical objects can be considered as paradigmatic cases of abstract entities, or abstract objects in their purest form.