Philosophy, Psychiatry, & Psychology

It is helpful of Thornton, and generous, to compare and contrast the view of reasons and causes proposed in Mind, meaning, and mental disorder (MMMD) with the very well-known and influential views of Donald Davidson. If our proposals were to generate a fraction of the interest due to Davidson’s, we would be indeed well satisfied.

Thornton summarizes two strands in Davidson’s thinking most directly relevant to reasons and causal role. The first is that we ascribe reasons to agents to make sense of their actions, and a fundamental principle of attribution is assumption of the agent’s overall rationality, broadly construed. This line of thought derives from Davidson’s views about conditions of so-called radical translation. The second strand is an argument which states that reasons can be causes of action: we distinguish from among the possible reasons for a particular action, the reason for which it was carried out, and the best or only way making this distinction is in terms of causal role.

Now these two lines of thought, as Thornton says, can appear problematic together. In particular, there have been influential arguments to the effect that the essential (constitutive) rationality of reasons is incompatible with them being causes. Thornton cites Frege and Wittgenstein on this. One strand in Frege’s critique of Psychologism was the observation that reasons are rationally structured—are in relations of inference, support, etc.—in contrast to being causally related. In the later Wittgenstein, what counts as following a rule, and hence as rational, cannot be analyzed in terms of causal relations (along Humean lines).

Therefore, we have on the one hand apparently convincing arguments that reasons cannot be causes, and on the other a convincing intuition that at least some reasons, specifically the reasons for particular actions, are causes. Davidson’s well-known escape from this cleft stick is the complicated and subtle doctrine of “Anomalous Monism.” It comprises at least the following two claims: that the reason for an action is identical with some brain event which is the cause of the action; and that reasons themselves and their relations to physical events (in the brain and behavior) cannot be brought under covering causal laws. The first claim—the “Monism”—is intended to secure the proposal that the reason for an action is its cause; the second claim concerning the non-law-like (“anomalous”) nature of psychophysical laws, is intended to preserve the principle that reasons have a constitutive rational structure which cannot be captured by causal relations.

The fundamental problem with all this, as [End Page 319] Thornton recognizes, is that reasons and causal role are insufficiently bound together. This is because the events which are the causes of action are the causes because they fall under physical laws, hence because of their physical properties, not because they fall under laws identified in any way in terms of reasons (relations between content, etc.), not because they have properties to with rationality.

The problem shows up very clearly, interestingly enough given the present context, in Davidson’s application of the theory to the phenomena of irrationality. Irrationality is explicated in terms of the causal efficacy of a reason overriding rational principles. This account presupposes, however, that rational principles and reasons generally have something like “force” or “power” in virtue of their constitutive rationality, and this is just what is excluded by the theory of “Anomalous Monism.”

Thornton correctly concludes that Davidson fails to reconcile or unite the rational and the causal. He then argues that we have not succeeded where Davidson failed. He succinctly summarizes various themes in MMMD relevant to this large problem area, including the neural encoding of content and functional vs. causal semantics, but significantly understates the very un-Davidsonian route we take to establish the main point, that reasons are causes. This fundamental opening argument sets the framework for the rest, including the means of resolving Davidson’s dilemma.

The route to the conclusion that reasons are causes proposed in MMMD is as follows. Explanations of action in terms of meaningful mental states (including beliefs, desires, and...