 Some Bayesians have tried to de-idealize Probabilism further, to set it free from the commitment that any credence ought to be as sharp as an individual real number, precise to every digit. For example, Walley (1991: ch. 2 and 3) develops a version of Probabilism according to which a credence is permitted to be unsharp in this way. A credence can be bounded by one or another interval of real numbers without being equal to any particular real number or any particular interval—even the tightest bound on a credence can be an incomplete description of that credence. This interval-bound approach gives rise to a Dutch Book argument for an even weaker version of Probabilism, which only implies: