 Part of the problem here, say critics, is that we do not know enough about what propensities are to adjudicate these issues. There is some property of this coin tossing arrangement such that this coin would land heads with a certain long-run frequency, say. But as Hitchcock (2002) points out, “calling this property a ‘propensity’ of a certain strength does little to indicate just what this property is.” Said another way, propensity accounts are accused of giving empty accounts of probability, à la Molière’s ‘dormative virtue’ (Sober 2000, 64). Similarly, Gillies objects to single-case propensities on the grounds that statements about them are untestable, and that they are “metaphysical rather than scientific” (825). Some might level the same charge even against long-run propensities, which are supposedly distinct from the testable relative frequencies.