Let us call a sparse property that is essentially dispositional a power. David Armstrong thinks that power properties cannot be fit into the actual world in a naturalistically respectable way. This paper shows this to be a problem for anyone who is not a Megarian actualist or a Lewisean modal realist but still wishes to appeal to unrealised possibilities. This is even a problem for Armstrong who tries to get his combinatorial theory of possibility to do the required solving. I show how Armstrong's combinatorialism is supposed to be in keeping with the spirit of actualism without being Lewisean or Megarian and expose some tensions in his efforts to do so. But these tensions aside, I claim that Armstrong's arguments against dispositionalism are still not very cogent. For they hinge on his rather ambiguous picture of naturalism and what he thinks it takes for something to be real. I then proceed to outline a less ambiguous kind of naturalism-Nomic Naturalism-instead. On this picture, we will see that power properties can come out as being naturalistically respectable. I then move on to claim that Armstrong's combinatorial account of truthmakers for modal truths is not the only option available to someone who does not wish to be a Lewisean modal realist or a Megarian actualist. There is a dispositonalist account available. I argue dispositionalism can provide us with a more robust picture of what makes our modal talk true than that offered by Armstrong's combinatorialism or Megarianism. And it does not have to do so in a way that shirks the spirit of actualism or needs to appeal to Lewisean modal realism.

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Since the mid-seventies, supervaluationism has been supported because of its capacity to give a conservative semantics for vague predicates and to avoid the so-called sorites paradox. As many opponents point out, however, this framework has something elusive and leaves several things unexplained. Dynamic semantics, which I present here, is introduced to interpret the elusiveness positively from an information-theoretic point of view. Thus the aim of the paper is to present a dynamic semantics for vague predicates as a revised version of supervaluationism.

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