Later Medieval Psychology: Deliberation, Love, and Mental Causation

Abstract

One of the most important moments in the history of philosophical psychology was the translation of Aristotle's De anima into Latin and its introduction into the curricula of medieval universities. Borrowing Peter King's phrase, the “neo-Aristotelian synthesis,” the doctrine integrating Aristotle's De anima, its Greek and Arabic commentaries, and the writings of the Church Fathers, particularly Saint Augustine, presented the philosophers of the later Middle Ages with a useful framework for investigating phenomena like thinking, willing, and their effects, namely, the psychology of faculties.¹ We find that many of the defining controversies of medieval philosophy were expressed in the language of faculty psychology, and especially the rational faculties of intellect and will, those principles in virtue of which human beings think and will, respectively. Although it might seem that studying these controversies (and the faculties of scholastic philosophy in general) has mere antiquarian value, the following articles show that nothing could be further from the truth. As well as being exemplars of scholarship in the history of philosophy, each of these articles, by tackling a major theme concerning the rational faculties, demonstrates the enduring value of studying the philosophy of the Middle Ages.

In “Deliberation and Rival Accounts of Free Choice in Medieval Philosophy,” Tobias Hoffmann investigates one of the central issues in the later medieval debate about freedom, namely, the role of deliberation in the exercise of free choice. Roughly, the dramatis personae of the debate fall into two camps: the intellectualists Thomas Aquinas, Godfrey of Fontaines, and John of Pouilly, and the voluntarists Walter of Bruges, Henry of Ghent, and John Duns Scotus. While the former argue that the deliberation of reason is essential to free choice and mediates the control we have over our actions, the latter deny this claim, arguing that human beings rather control their acts directly, that is, by means of the will. In navigating the views of these two camps, Hoffmann elucidates the major developments in later medieval theorizing about deliberation and free choice, explaining challenges along the way.²

In “Motivation and Beyond? The Role of Love (amor) in Ockham's Theory of Action,” Sonja Schierbaum takes up the theme of intentional action, presenting William of Ockham's action theory as an alternative to the Humean tradition, according to which desire and belief are the starting points of intentional action. Although it does make sense that, in particular, the appetitive starting point of any intentional action is a desire—I do some action because I desire something I can attain by means of that action—Schierbaum observes that so explaining intentional action leaves a fundamental question unanswered: Why do we desire anything at all? Ockham's action theory is an alternative to the Humean tradition because it grounds desire in a more basic act of will—love. Indeed, it is because I love myself, for example, appreciating myself not merely as a means but also as an end, that I desire any good for myself.³

Finally, in “Aquinas on Dualist Mental Causation,” Can Laurens Löwe explores yet another theme related to the rational faculties, examining a classic philosophical problem, namely, how the non-physical mind can act on the body, what Löwe refers to as the problem of non-physical mental causation. In the later medieval context, this is the problem of how the immaterial, rational soul moves the body through its intellect and will. Löwe focuses particularly on Thomas Aquinas, who offers an attractive solution to the problem.⁴ Curiously, although one might think that this solution would be based on Aquinas's hylomorphism, his view that the soul is the “form” of the body, Löwe argues that it is rather based on Aquinas's theory of a special, spiritual type of contact that obtains between the soul and the body—contact of power. In his contribution, Löwe carefully analyzes the notion of contact of power in the broader context of addressing the problem of non-physical mental causation.

When we think about the philosophical issues motivating these articles—the relationship between free choice and deliberation, the explanation of intentional action, and the possibility of the non-physical acting on the physical—we notice that they are issues of enduring interest. The modern debate about the compatibility of free will and determinism, for example, with its concern about understanding what grounds control over our actions, treads on ground that would be familiar to later medieval intellectualists and voluntarists about free choice. If, as Hoffmann argues, the difficulties encountered by intellectualists and voluntarists suggest that free choice is “in principle beyond full comprehension,” could similar conclusions be drawn about the modern debate? Concerning the explanation of intentional action, Schierbaum herself observes that the recognition of love as an act of the will more basic than desire makes possible novel strategies for theorizing about practical rationality, for example. And, as Löwe notes, appealing to powers in explaining the causal relation between the mind and the body is not unfamiliar to contemporary metaphysicians. Although Aquinas's own solution to the problem of non-physical mental causation might fail, it is striking that, by adopting a spatial conception of the mind, Aquinas exemplifies a dualistic strategy discussed by some modern-day philosophers.⁵ At every turn, we are reminded that philosophy is a dialogue in which the great thinkers of the Middle Ages are continuing interlocutors.

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