In his target article, Gerard O’Brien addresses the question of “how the specifically representational properties of mental phenomena can be causally efficacious of behavior” (this collection, p. 12). When he does so, there are two parts of the problem to be considered: the first is explaining how mind matters, and the second is showing how an answer can prevail in the light of the content causation problem. Considering the first part in isolation, O’Brien provides an interesting answer. He translates our talk of representation into causal vocabulary, thereby making it possible to reach a concept of causally efficacious representational content. In order to understand how O’Brien’s account needs to be assessed with regard to the second part, one first needs to reconstruct which background assumptions make the content causation problem so pressing.
I am convinced that the issues of reduction and the relational/intrinsic property distinction need to be addressed in order to understand whether and how the content causation problem can motivate an account like O’Brien’s. His account takes as a starting point that representational content has a relational character, but should not be understood in terms of relational properties. Rather, as we have seen, it should be understood in terms of dispositions—which can, if manifested, establish causal relations, but are not relational by themselves. I hope to have provided a reconstruction of how this starting point is used to reach the conclusion that, as O’Brien formulates it, “resemblance theories appear obligatory, since they alone offer some prospect for explaining how mind matters” (this collection, p. 12).
If this is correct, there remains one question: whether resemblance theories of the proposed kind might themselves indicate that the content causation problem rests on a mistake. The problem presupposes further problems about the role of relational and intrinsic properties that need not be addressed in order to account for the causal efficacy of representational content. The content causation problem’s not arising in the first place would, of course, not undermine O’Brien’s highly interesting account. It is only that this problem could no longer be used to motivate the argumentative steps he takes. Still, his account is illuminating for many other reasons, such as translating mysterious talk about “being about” into naturalistic terminology. However, whether we can regard the content causation problem as solved or rather as successfully rejected is not clear; but instead of worrying about this problem, we might now turn towards the details of O’Brien’s account. An interesting starting point for such further inquiry might be to try to reach a better understanding of the role and the kind of dispositions and vehicles involved in causal processes, for they form two of the key concepts in O’Brien’s theory.