The chapter shows that more sophisticated difference-making theories of causation that draw on so-called causal models can accommodate mental causation too. Causal modelling theories invoke more complex relations of difference-making than the simple principle about causation that was used in previous chapters. These relations of difference-making are represented by causal models. Accommodating mental causation – either in the non-reductive physicalist case or in the dualist case – calls for some heterodoxy in model-building. If the heterodox models are allowed, however, they prove useful not merely for explaining mental causation, but also for capturing the distinction between higher–level causes that are explanatorily relevant and higher-level causes that are not. The chapter also discusses the interventionist theory, an especially prominent member of the causal modelling family, in relation to mental causation.

The chapter uses the principle according to which difference-making or counterfactual dependence is sufficient for causation to show that there are physical effects of mental causes. If non-reductive physicalism is true, applying the principle is straightforward. The principle also yields higher-level causes that are not mental but might be considered problematic. These causes are best diagnosed as causes that have little explanatory relevance. If dualism is true, applying the principle about causation in order to show the existence of mental causation is less straightforward, but still possible. In order to avail themselves of the principle, dualists need to assume that the laws that connect the mental and physical realms have a special status. Rival approaches according to which mental causation or human agency require the transference of a physical quantity or of a power are in conflict with empirical results. The account of mental causation by counterfactual dependence, by contrast, squares with these results.

The chapter deals with the exclusion problem. How can mental events have physical effects if these effects already have physical causes? Even if this is possible in principle, would this not yield a situation like in a firing squad, where the victim’s death is overdetermined by the firings of the squad members? And would it not be implausible that the situation is like this whenever there is mental causation? If a difference-making approach to causation is adopted, these questions can be answered in a satisfactory way. Although mental and physical causes might nominally overdetermine their physical effects, cases of mental causation are sufficiently dissimilar to typical cases of overdetermination not to be problematic. Unlike in cases of mental causation (on the account offered here), in typical cases of overdetermination, the individual causes do not make a difference to the effect. The exclusion problem is harder to solve if it is formulated in terms of sufficient causes, but no commitment to sufficient causation follows from the account of mental causation in terms of difference-making.

The resulting picture of mental causation, which is summarized in this chapter, has repercussions for debates about the nature of mind. If virtually all theories about the nature of mind can solve the problems of mental causation, then arguments from mental causation against certain theories become irrelevant in debates between reductive physicalists, non-reductive physicalists, and dualists. Questions about the nature of mind will have to be decided independently of the problems of mental causation.

The chapter lays the groundwork about the mind and causation. It characterizes theories about the nature of mind: physicalism, particularly non-reductive physicalism, and dualism, particularly naturalistic dualism. It then turns to causation, its relata, and counterfactual conditionals, the claims that express difference-making. Counterfactual conditionals, their general truth-conditions and logical relations are introduced, as are issues about how to evaluate them. A principle about causation in terms of counterfactual conditionals is defended that is crucial for later arguments. According to this principle, an event causes a later event if the later event would not have occurred had the first event not occurred. Although plausible, the principle needs refinement to deal with some prima facie difficulties. Assumptions need to be made about how to evaluate counterfactual conditionals like ‘If the first event had not occurred, then the second event would not have occurred’. Rival views about causation in terms of transference conflict with the counterfactual principle in so-called cases of double prevention. The conflict should be resolved in favour of the counterfactual principle.

The introduction describes the main problems of mental causation, their interrelations, and their history. The first problem is the interaction problem, the problem of how the mind and the physical world can interact at all. The second problem is the exclusion problem, the problem of how the mind can have physical effects given that these physical effects already have physical causes. How severe the problems are depends on the nature of the mind. The more intimate the relation between the mental and the physical, the more pressing the problems become. How severe the problems are also depends on the nature of causation. If causation requires the transference of a physical quantity, the problems are much harder to solve than if it suffices for causation if the cause makes a difference to the effect. The introduction outlines the history of the problems from Descartes to the twentieth century.