 Piling: Even if swapping does not give us a reason to prefer SI over PI, perhaps its close cousin ‘piling’ does. Consider a particular red rose. Given trope theory, this rose is red because it is partly constituted by a redness-trope. But what is to prevent more than one—even indefinitely many—exactly similar red-tropes from partly constituting this rose? Given PI: nothing. It is however far from clear how one could empirically detect that the rose has more than one redness trope, just like it is not clear how one could empirically detect how many redness tropes it has, provided it has more than one. This is primarily because it is far from clear how having more than one redness trope could make a causal difference in the world. But if piling makes no empirical/causal difference, then given a (plausible) Eleatic principle, the possibility of piling is empty, which means that PI ought to be rejected (Armstrong 1978: 86; cf. also Simons 1994: 558; Schaffer 2001: 254, fn. 11).