Even if we accept dilation as a fact of life for the imprecise probabilist, it is still weird. Even if all of the above argument is accepted, it still seems strange to say that your belief in \(H\) is dilated, whatever you learn. That is, whether you learn \(Y\) or \(Y'\), your posterior belief in \(H\) looks the same: \([0,1]\). Or perhaps, what it shows to be weird is that your initial credence was precise.