 In the preceding paragraphs, we have canvassed Prior et al.’s arguments for their Distinctness Thesis. Using these arguments as a stepping stone, Prior (1985, chapter 7) and Jackson (1998) advance the functionalist view that disposition \(D\) is a second-order property, the property of having some first-order property or other that plays the causal role corresponding to \(D\). It seems to be a consequence of this view that dispositions do no causal work (see  section 6  below). For if having, say, the property of fragility is a matter of having a first-order property that plays the causal role associated with fragility, then it would seem that it is this first-order property, not the second-order property, that does all causal work. It would seem, then, that the functionalist view is open to the objection that it predicts dispositions to be ‘causally superfluous’ in a way that, intuitively, they are not. (See Mumford 1998; Martin &amp; Heil 1999; Heil 2003, 2005 for this objection, and see  section 6  below for further discussion.)