If the grounding relationship is metaphysically contingent, then quiddities are merely 'along for the causal ride' and make no distinctive causal contribution.

A third recent objection is that Russellian monism, despite its aims, fails to adequately integrate consciousness into physical causation. One version of this objection begins with the premise that, on Russellian monism, a single type of physical disposition might have been grounded by a distinct quiddity from the quiddity that actually grounds it (Howell 2015; cf. Robinson 1993). For example, if in the actual world quiddity Q1 grounds negative charge, then there is a metaphysically possible wor