Dispositions all the way round
Simon Blackburn has argued that science finds only dispositional properties. If true, this is surprising: we think of the world as containing categorical properties too. But Blackburn thinks that our difficulties go further than this: that the idea of a world containing just dispositional properties is not simply surprising, but incoherent. The problem is made clear, he argues, when we have a counterfactual analysis of dispositions, and then understand counterfactuals in terms of possible worlds.