 In reply to the Two Urns Case, objective Bayesians have defended one or another version of the Indifference Principle. White (2010) does it while maintaining that credences ought to be sharp. Weatherson (2007: sec. 4) defends a version that allows credences to be unsharp. Eva (2019) defends a version that governs comparative probabilities rather than numerical credences. For more on this debate, see the survey by Mahtani (2019) and the entry on  imprecise probabilities.