- Does what we think ever affect what we do? The answer to this question may seem obvious; of course, having the thoughts that we have leads us to do what we do. But philosophers have recently cast doubt on the relevance of what we think to what we do. Mental causation2 — the causation3 of what we do by what we think — becomes a problem against a particular metaphysical background. My aim is twofold:
- first, to root out the metaphysical assumptions that generate the problem of mental causation4 and to show that they preclude its solution;
- second, to dissolve the problem of mental causation5 by motivating rejection of one of the metaphysical assumptions that give rise to it.
- There are three features of this metaphysical background picture that are important for our purposes.
- The first concerns the nature of reality: all reality depends on physical reality, where physical reality consists of a network of events.
- The second concerns the nature of causation6: causation7 is conceived of as 'objective', a 'real relation' in nature, instances of which are independent of anyone's explanatory interests.
- The third concerns the conception of behaviour: behaviour is to be understood in terms of events with certain kinds of internal causes.
- The internal events that cause behavioural events (are thought to) have various kinds of properties, some physical and some intentional. The intentional (or mental) properties are what I shall call 'content-properties'; a desire to get a beer from the refrigerator, a belief that Summer Squall will win the Kentucky Derby. As I am using the term, 'content-properties' are e.g. those properties in virtue of which beliefs are themselves true or false. When we explain behaviour in terms of a person's reasons, what we cite in explanations are various content-properties — properties determined by what she believes, what she desires, and so on. In this picture, these content-properties are attributed to the person's internal events that cause the behaviour.
- In the wake of these assumptions, suspicion about mental causation8 comes naturally: assuming that a bit of behaviour is an event caused by internal events that have content-properties (such as a belief that you left your keys on the counter), it may well be that content-properties of the cause are causally inert. To borrow an example from Fred Dretske (1989), the soprano may be making meaningful sounds when she hits the glass-shattering high C, but the meaning is irrelevant to the properties (e.g. amplitude) of the sound that causes the glass to shatter. The fear concerning mental causation9 is that all content-properties may be like those of the soprano's high C.
- Understood against this background, the question with which we started, 'how can what we think affect what we do?', is recast as this question: 'how can content-properties of internal events be causally relevant to producing behavioural events?' The problem of mental causation10 is to answer this question.
- A widespread assumption about the nature of explanation produces a corollary to the problem of mental causation11. The thesis about explanation is that an explanation of a behavioural event mentions a causally relevant property of an internal event that causes the behaviour. Given this thesis and the background picture, if content-properties are causally irrelevant, then they are also explanatorily irrelevant. In that case, the shattering of the glass cannot be explained by what the high C meant. Moreover, if content-properties turned out to be causally, and hence explanatorily, irrelevant to behaviour, then (again, in light of the background picture) we should conclude that reasons, identified by content-properties, have never explained anything that anyone has ever done. It would not be just that putative explanations by reasons turned out to be second-class explanations; rather, they would not be explanatory at all.
- What I want to show is that, given this metaphysical picture, the problem of mental causation12 is insoluble. We simply have no answer to the question 'How can mental events, in virtue of having mental properties, make a difference to behaviour?' because the very assumptions that generate the question render it unanswerable. Moreover, I want to show that the metaphysical assumptions with which we began inevitably lead to scepticism not only about the efficacy of contentful thought, but about macro-causation13 generally. But if we lack warrant for claiming that macro-properties are generally causally relevant, and if we take explanations to mention causes, then most, if not all, of the putative explanations that are routinely offered and accepted in science and everyday life are not explanatory at all. So, I shall argue, we have an impasse: we must either give up (part of) the metaphysical background picture or give up almost all explanations that have ever been offered for anything. Since the generalization of the problem to macro-causation14 depends only on the theses about reality and causation15, I shall here neither examine the conception of behaviour as events with internal causes nor the conception of beliefs as internal states. Rather, I shall focus on the theses about reality and causation16, and suggest that we stick with the explanations that have proved their worth and let the metaphysical chips fall where they may.
Footnote 1: Footnotes omitted.
Text Colour Conventions (see disclaimer)
- Blue: Text by me; © Theo Todman, 2018
- Mauve: Text by correspondent(s) or other author(s); © the author(s)