Truthmakers

Divers spends a good deal of Chapter 4 evaluating the claim that GR provides truthmakers for modal claims (utterances? sentences? propositions?). I thought it would be helpful to say a bit more about what truthmakers are supposed to be. Here's Armstrong on truthmakers:

"The idea of a truthmaker for a particular truth, then, is just some existent, some portion of reality, in virtue of which that truth is true. The relation, I think, is a cross-categorical one, one term being an entity or entities in the world, the other being a truth. (I hold that truths are true propositions, but will leave this matter aside . . . ) To demand truthmakers for particular truths is to accept a realist theory for these truths. There is something that exists in reality, independent of the proposition in question, which makes the truth true. The 'making' here is, of course, not the causal sense of 'making'. The best formulation of what this making is seems to be given by the phrase 'in virtue of'. It is in virtue of that independent reality that the proposition is true. What makes the proposition a truth is how it stands to this reality."

"Two questions immediately arise. First, do truthmakers actually necessitate their truths, or is the relation weaker than that, at least in some cases? Second, do all truths have truthmakers, or are there some areas of truth that are truthmaker-free, modal truths, for instance? My answers to these questions are, first, that the relation is necessitation, absolute necessitation, and, second, that every truth has a truthmaker. I will call these positions respectively 'Truthmaker Necessitarianism' and 'Truthmaker Maximalism'."- D. M. Armstrong, pp. 5, Truth and Truthmakers, 2004, Cambridge University Press.