Psychophysical Causation and a Pragmatist Approach to Human Behavior

Jochen Fahrenberg and Marcus Cheetham have performed a valuable service by conducting and presenting an empirical study of some basic philosophical assumptions of psychologists, philosophers, and scientists. Well-designed, large-scale empirical studies of this kind are all too rare in the literature. Those of us interested in the human sciences are rather in the dark about the assumptions of others working in our own and related fields. For the most part, we are privy only to the philosophical assumptions of friends and colleagues we know intimately and of those relative few who publish their views. We can only speculate about the views of the countless others with whom we have not had the opportunity to establish direct philosophical discourse. The findings presented by Fahrenberg and Cheetham give us an intriguing glimpse at some of the key philosophical assumptions of a variety of clinicians and academics who are interested in human nature and the human sciences.

My aim in this commentary is to present an interpretation of a central finding of this questionnaire study: that psychologists were more likely than philosophers and scientists to embrace “psychophysical causation” as a part of their philosophical worldview. It is not, I think, too much of an oversimplification to define psychophysical causation as the presumption that mental events and physical events can cause other mental events and physical events. Psychophysical causation can be distinguished from other positions on the mind–body relation, some of which Fahrenberg and Cheetham mention in their article. Among these alternative positions is epiphenomenalism, the position that physical events cause other physical events and can cause mental events, but that mental events themselves have no causal power. Another philosophical position distinct from psychophysical causation is monism, which holds that all events in the world in general (and in human beings in particular) are physical and are best described in physical terms. Fahrenberg and Cheetham do not describe the multiple forms of monism in detail, but it is worth noting that reductive materialism (Wilson 1998) and eliminative materialism (Churchland 1981) are two highly developed forms of the kind of monism to which they allude. It is beyond the scope of this commentary to explore the differences between the two, but suffice it to say that both these forms of materialism reject the legitimacy of mental events or the mental vocabulary that refers to such events.

It is also beyond the scope of this commentary to advance arguments either for or against psychophysical causation in the philosophy of mind. The concept of psychophysical causation certainly has multiple proponents among philosophers, including those who are ontological monists. The compelling nonreductive materialism of a philosopher such as Terence Horgan, for example, suggests the viability of combining ontological monism with methodological pluralism. In a book chapter entitled “Nonreductive Materialism and the Explanatory Autonomy of Psychology,” Horgan (1993) developed the position that the world is entirely physical (i.e., there are no disembodied minds, persons, or other entities) but is so complex that it can only be understood and explained by employing many vocabularies and methodologies, spanning “the microphysical, neurobiological, macrobiological, and psychological.” This kind of methodological pluralism in the philosophy of mind can be disputed on conceptual grounds, but it seems to be at least as justifiable (and perhaps more justifiable) when compared with other well-defined positions on the mind–body relation.

The appeal of nonreductive materialism and psychophysical causation comes into particularly clear focus in contexts where our philosophical concerns are pragmatic in nature. In other words, when we need to achieve practical goals in our everyday lives, we usually benefit from a philosophy that provides us with the flexibility to use a broad range of ideas, conceptual tools, and causal hypotheses that can be adapted to specific needs and challenges. Nonreductive materialism regards the world as a purely physical place, but ensures this kind of conceptual and methodological flexibility when it comes to explaining and predicting complex human experience and behavior. “Typically, certain context-relative features of discourse,” Horgan wrote (1993, 298), “will determine, in a given...