 Objection 2: Limiting relative frequencies are not well-defined. To define the limiting relative frequency of \(A\) at a world \(w\), we require that there is a unique sequence of extensions of the algebra each of which contains more propositions that are relevantly similar to \(A\) than the previous extension, and a corresponding sequence of relative frequencies of truths amongst the propositions like \(A\) in the corresponding algebra. But the assumption of such a unique sequence is extremely controversial and the problems to which it gives rise have haunted hypothetical frequentism about objective probability (Hájek 2009).