Donald DavidsonDonald Davidson argued in his influential 1963 essay Actions, Reasons, and Causes that the relation between a reason and an action was some kind of causal connection. Ludwig Wittgenstein had claimed in his Blue and Brown Books that reasons and actions were not related as causes and effects. This led several other philosophers to deny that reasons were causes, including Gilbert Ryle, G. E. M. Anscombe, and Stuart Hampshire. On the other hand, Wittgenstein's colleague and translator, Frank Ramsey, developed a causal theory of knowledge called reliabilism. Davidson agreed that reasons and actions have a purposeful or teleological relation, but that this does not prevent a causal relation. Today many philosophers have reverted back to Wittgenstein and describe the teleological relation as "non-causal" and not nomological. They do this largely to prevent the argument that our actions are caused and therefore determined, prohibiting human freedom. Among the non-causal libertarians are Carl Ginet, Stewart Goetz, Hugh McCann, and David Widerker. Davidson states the case simply:
Noting that nonteleological causal explanations do not display the element of justification provided by reasons, some philosophers have concluded that the concept of cause that applies elsewhere cannot apply to the relation between reasons and actions, and that the pattern of justification provides, in the case of reasons, the required explanation. But suppose we grant that reasons alone justify actions in the course of explaining them; it does not follow that the explanation is not also - and necessarily - causal. Indeed our first condition for primary reasons is designed to help set rationalizations apart from other sorts of explanation. If rationalization is, as I want to argue, a species of causal explanation, then justification, in the sense given, is at least one differentiating property. How about the other claim: that justifying is a kind of explaining, so that the ordinary notion of cause need not be brought in? Here it is necessary to decide what is being included under justification. It could be taken to cover only what is called for: that the agent have certain beliefs and attitudes in the light of which the action is reasonable. But then something essential has certainly been left out, for a person can have a reason for an action, and perform the action, and yet this reason not be the reason why he did it. Central to the relation between a reason and an action it explains is the idea that the agent performed the action because he had the reason. Of course, we can include this idea too in justification; but then the notion of justification becomes as dark as the notion of reason until we can account for the force of that 'because'.A few years later, Davidson claimed that mental events are anomalous, they are not (as physical events are) describable by strict deterministic laws that can be used to predict our thoughts. Nevertheless, he believed that mental events can be causally related to physical events. Can he have it both ways? Davidson admitted he was in sympathy with Immanuel Kant and might be only explaining away an apparent contradiction between the mental and the physical, resolving a kind of antinomy, and perhaps the paradox of free will? In his 1970 essay "Mental Events" (in Experience and Theory, Univ of Massachusetts Press, 1970), Davidson describes his "Anomalous Monism":
In order to allow mental events to cause physical events, yet not be reducible to them, Davidson developed the following set of arguments. Mental events such as perceivings, rememberings, decisions, and actions resist capture in the nomological net of physical theory. How can this fact be reconciled with the causal role of mental events in the physical world? Reconciling freedom with causal determinism is a special case of the problem if we suppose that causal determinism entails capture in, and freedom requires escape from, the nomological net. But the broader issue can remain alive even for someone who believes a correct analysis of free action reveals no conflict with determinism. Autonomy (freedom, self-rule) may or may not clash with determinism; anomaly (failure to fall under a law) is, it would seem, another matter. I start from the assumption that both the causal dependence, and the anomalousness, of mental events are undeniable facts. My aim is therefore to explain, in the face of apparent difficulties, how this can be. I am in sympathy with Kant when he says,it is as impossible for the subtlest philosophy as for the commonest reasoning to argue freedom away. Philosophy must therefore assume that no true contradiction will be found between freedom and natural necessity in the same human actions, for it cannot give up the idea of nature any more than that of freedom. Hence even if we should never be able to conceive how freedom is possible, at least this apparent contradiction must be convincingly eradicated. For if the thought of freedom contradicts itself or nature ... it would have to be surrendered in competition with natural necessity.Generalize human actions to mental events, substitute anomaly for freedom, and this is a description of my problem. And of course the connection is closer, since Kant believed freedom entails anomaly. Now let me try to formulate a little more carefully the 'apparent contradiction' about mental events that I want to discuss and finally dissipate. It may be seen as stemming from three principles. The first principle asserts that at least some mental events interact causally with physical events. (We could call this the Principle of Causal Interaction.) Thus for example if someone sank the Bismarck, then various mental events such as perceivings, notings, calculations, judgements, decisions, intentional actions, and changes of belief played a causal role in the sinking of the Bismarck. In particular, I would urge that the fact that someone sank the Bismarck entails that he moved his body in a way that was caused by mental events of certain sorts, and that this bodily movement in turn caused the Bismarck to sink. Perception illustrates how causality may run from the physical to the mental: if a man perceives that a ship is approaching, then a ship approaching must have caused him to come to believe that a ship is approaching. (Nothing depends on accepting these as examples of causal interaction.) Though perception and action provide the most obvious cases where mental and physical events interact causally, I think reasons could be given for the view that all mental events ultimately, perhaps through causal relations with other mental events, have causal intercourse with physical events. But if there are mental events that have no physical events as causes or effects, the argument will not touch them. The second principle is that where there is causality, there must be a law: events related as cause and effect fall under strict deterministic laws. (We may term this the Principle of the Nomological Character of Causality.) This principle, like the first, will be treated here as an assumption, though I shall say something by way of interpretation. The third principle is that there are no strict deterministic laws on the basis of which mental events can be predicted and explained (the Anomalism of the Mental). The paradox I wish to discuss arises for someone who is inclined to accept these three assumptions or principles, and who thinks they are inconsistent with one another. The inconsistency is not, of course, formal unless more premises are added. Nevertheless it is natural to reason that the first two principles, that of causal interaction and that of the nomological character of causality, together imply that at least some mental events can be predicted and explained on the basis of laws, while the principle of the anomalism of the mental denies this. Many philosophers have accepted, with or without argument, the view that the three principles do lead to a contradiction. It seems to me, however, that all three principles are true, so that what must be done is to explain away the appearance of contradiction, essentially the Kantian line.
The fact is that under Davidson's anomalous monism, mentality does no causal work. Remember: in anomalous monism, events are causes only as they instantiate physical laws, and this means that an event's mental properties make no causal difference.This is in apparent contradiction with Davidson's first premise above. But Davidson's third premise states that there are no "strict psycho-physical laws," so Kim has a point. Davidson apparently wants mental and physical events to have causal relations, but without "strict deterministic laws." This may be compatible with two-stage models of free will, if Davidson thinks of the mental as the anomalous indeterministic free part and the physical as the lawful deterministic will part. In two-stage models of free will, the first stage generates alternative possibilities, at least some of which can be randomly generated, so are uncaused. Since they are only unrealized, unactualized possibilities, one can describe them as Kim does - as doing "no causal work." In the concluding paragraphs of "Mental Events," Davidson argues that the anomalism of the mental is a necessary condition for viewing action as autonomous. He thinks he has resolved a paradox (essentially the problem of free will) - the efficacy of thought and purpose in the material world, and their freedom from law.
Two features of mental events in their relation to the physical — causal dependence and nomological independence — combine, then, to dissolve what has often seemed a paradox, the efficacy of thought and purpose in the material world, and their freedom from law. When we portray events as perceivings, rememberings, decisions and actions, we necessarily locate them amid physical happenings through the relation of cause and effect; but that same mode of portrayal insulates mental events, as long as we do not change the idiom, from the strict laws that can in principle be called upon to explain and predict physical phenomena. Mental events as a class cannot be explained by physical science; particular mental events can when we know particular identities. But the explanations of mental events in which we are typically interested relate them to other mental events and conditions. We explain a man's free actions, for example, by appeal to his desires, habits, knowledge and perceptions. Such accounts of intentional behavior operate in a conceptual framework removed from the direct reach of physical law by describing both cause and effect, reason and action, as aspects of a portrait of a human agent. The anomalism of the mental is thus a necessary condition for viewing action as autonomous. I conclude with a second passage from Kant:It is an indispensable problem of speculative philosophy to show that its illusion respecting the contradiction rests on this, that we think of man in a different sense and relation when we call him free, and when we regard him as subject to the laws of nature. ... It must therefore show that not only can both of these very well co-exist, but that both must be thought as necessarily united in the same subject...