 The dominant cause challenge can be raised both as part of the descriptive project and as part of the functional project. Within the descriptive project the claim is that it is part of our commonsense notion of causation that events only have a small number of causes. Within the functional project the claim becomes that singling out a small set of events as an event’s causes serves important purposes in our cognitive architecture that would not be fulfilled by any notion of cause allowing for an event to have an arbitrarily large set of causes. This claim might be supported by pointing out that causal claims are used to assign responsibility or blame, to single out factors that are particularly amenable to interventions into a system and for control, or to single out factors that we may find particularly salient in a given context—functions that all appear to require zeroing in on only a small number of dominant factors as an event’s causes.