  A similar argument is based on the possibility of tropes swapping positions in space (Campbell 1990, 71). “Property swapping,” it is claimed, is an unreal possibility since property swapping would make no difference to the world. (Note that the cross-object version of this objection cannot get off the ground if tropes are not transferable between objects, a view that is found in (Martin 1980), although Martin rejects trope primitivism since he posits substrata in addition to tropes).