No capacities in a deterministic universe
Fischer’s rendition of compatibilism is particularly attractive because it provides a clear mechanistic analysis of the notion of “capacity” and a related procedure for checking whether a particular mechanism possesses the requisite capacities:
. . . a mechanism’s reacting differently to a sufﬁcient reason to do otherwise in some other possible world shows that the same kind of mechanism can react differently to the actual reason to do otherwise. This general capacity of the agent’s actual-sequence mechanism – and not the agent’s power to do otherwise – is what helps to ground moral responsibility. (Fischer and Ravizza 1998, 73, my emphasis)
Fischer offers a synchronic account of moderateness in regards to reasons-responsiveness – a synchronic account of what it means for a mechanism to embody capacities. I call it “synchronic” because it stipulates that to ascertain whether a mechanism from which a person’s action issues is moderately reasons-responsive, we check how that mechanism behaves in this time slice across other possible worlds in which it is presented with similar kinds of reasons. And to do that, in turn, we are told to imagine relevantly similar situations to the actual situation and then to reﬂect on how that mechanism would behave in those situations. If a person’s inappropriate action issues from a mechanism which in at least one other possible world issues in a non-inappropriate action, then their inappropriate action issues from a mechanism with the general capacity to respond in a non-inappropriate way. Thus, the agent is blameworthy in Fischer’s view precisely because they do not exercise a capacity which they possess in virtue of possessing the mechanism that embodies or implements that capacity.