 The arbitrariness problem, moreover, stymies any compelling connection between logical probabilities and rational credences. And a further problem remains even after the confirmation function has been chosen: if one’s credences are to be based on logical probabilities, they must be relativized to an evidence statement, \(e\). Carnap requires that \(e\) be one’s total evidence—the maximally specific information at one’s disposal, the strongest proposition of which one is certain. But perhaps learning does not come in the form of such ‘bedrock’ propositions, as Jeffrey (1992) has argued — maybe it rather involves a shift in one’s subjective probabilities across a partition, without any cell of the partition becoming certain. Then it may be that the strongest proposition of which one is certain is expressed by a tautology \(T\) — hardly an interesting notion of ‘total  evidence’.[4]