  Finally, there is Causal Nominalism, according to which what makes it true that a is F is that a would stand in certain causal relations given certain circumstances. In other words, the claim is that for a to be F is for the theory that which charts out the functional role of F-particulars to be true of a (Whittle 2009, 246). F-particulars will resemble each other in realising the same functional role, but this does not collapse Causal Nominalism into Resemblance Nominalism, since such resemblances are not what explains why a is F, but a consequence of what explains that, namely the fact that such particulars realise a certain functional role (Whittle 2009: 255). Similar reasons might also suggest that Causal Nominalism does not collapse into any of the other nominalisms. But it has been argued that to be thoroughly nominalistic, Causal Nominalism owes a nominalistic account of what it is for different particulars to realise the same functional role, and such an account can only be in terms of any of the nominalisms distinguished above, in which case Causal Nominalism collapses into some other form of nominalism (Tugby 2013).