Synergy and disagreement

Synergy effects are taken to occur if equally well-informed and competent people agree, or nearly agree, that a certain proposition is true (or that it is false); these people should then take their agreement as confirmation that their reasoning has been correct and adopt an even greater (or lower) credence towards the issue under debate. Thus understood, synergy effects appear to occur quite frequently. The paper argues that a necessary condition for synergy effects to occur is that we cannot take our evidence at face value. This might happen either because we should be epistemically cautious in cases of presumed asymmetrical proneness to error (cases in which the relevant evidence supports either credence 1 or credence 0 towards the proposition at issue are the prime examples hereof); or because background information rules out the option supported by our remaining evidence. This result preserves the intuitive appeal of considerations on synergy but significantly restricts their scope. It thereby also reconciles considerations on synergy with a natural interpretation of conciliatory views on peer disagreement.