 Bradley’s regress arguments have been most widely discussed within the context of the realists’ two-category ontology of particulars and universals. The challenge in this context is to provide an ontological ground of unity of particulars and universals, and the worry is that any appeal to a relation R (of instantiation, exemplification, etc.) to unify a particular a with its respective property universal F sets off an infinite regress of relations, similar to the regresses described by Bradley. In the light of this problem, some realists such as Olson (1987), and Armstrong (1997) have argued that it is a third entity - the fact or state of affairs of a being F that provides the ontological ground of unity of a and Fness as well as the truthmaker for the truth that “a is F”. According to critics (see, for instance, Vallicella 2000 and 2002), this approach instead of solving the problem of unity of particulars and universals, merely reframes it as the one threatening the very possibility of there being such entities as facts or states of affairs. Similar worries have arisen for trope theorists that embrace a two-category ontology of particulars and tropes. Philosophers such as C.B. Martin (1980) and Daly (1997) have worried that an appeal to a relation of inherence in the context of unfying a substratum and its property trope would lead to an infinite regress of inherence relataions.