 This bridge principle might be construed as part of a definition or as a necessary truth that captures the nature of credences, or understood as a norm that jointly constrains credences and betting dispositions (Christensen 1996; Pettigrew 2020a: sec. 3.1). The hope is that, through this bridge principle or perhaps a refined one, bad credences generate bad symptoms in betting dispositions. If so, a close look at betting dispositions might help us sort out bad credences from good ones. This is the strategy that underlies Dutch Book arguments.