 Suppose a coin is to be flipped 1000 times. And suppose that \(A\) is the proposition Heads on toss 1. And suppose that the propositions that are relevantly similar to \(A\) in algebra \(\mathcal{F}\) are: Heads on toss 1, …Heads on toss 1000. Finally, suppose that \(w\) is a possible world; a way that the world might be. In fact, throughout this article, we need not quantify over genuine possible worlds, which are maximally specific ways the world might be; we need only quantify over ways the world might be that are specific enough to assign truth values to each of the propositions in the algebra \(\mathcal{F}\). Let’s call these possible worlds relative to \(\mathcal{F}\) and let \(\mathcal{W_F}\) be the set of them for a given algebra \(\mathcal{F}\). Then the relative frequency of \(A\) at \(w\) (written \(\mathrm{Freq}(\mathcal{F}, A, \sim, w)\)) is the proportion of the propositions relevantly similar to \(A\) that are true at \(w\): that is, the frequency of heads amongst the 1000 coin tosses at that world. For instance, if every second toss lands heads at \(w\), or if the first five hundred land heads and the rest land tails at \(w\), then \(\mathrm{Freq}(\mathcal{F}, A, \sim, w) = \frac{1}{2}\). If every third toss lands heads at \(w\), then \(\mathrm{Freq}(\mathcal{F}, A, \sim, w) = \frac{1}{3}\). And so on.