This volume contains 14 papers on Aristotelian and non-Aristotelian medieval accounts of weakness of will, many of which have not yet been the object of scholarly writing. The papers give insight into a variety of accounts of practical rationality that were directly or indirectly influential on modern thinkers. The temporal framework of the volume exceeds the Middle Ages on both ends by including Aristotle and authors from the Renaissance and the Reformation.

Tobias Hoffmann, Jörn Müller, and Matthias Perkams, “Der mittelalterliche Beitrag zum Problem der Willensschwäche,” pp. 5–37: This paper surveys the contemporary discussion and the history of the problem of weakness of will and argues that the contributions of medieval authors have been widely neglected. Many prominent medieval thinkers provide extensive discussions of weakness of will in its own right. Others examine related problems in contexts such as free will, the unity of virtue, sin from passion, conscience, original sin, and angelic sin. The medieval accounts of weakness of will offered refined analyses of the relation between passions, intellectual failure, corruption of the will, and moral responsibility.

Terence H. Irwin, “Will, Responsibility, and Ignorance: Aristotelian Accounts of Incontinence,” pp. 39–58: According to Aristotle, the incontinent person has the right choice, but acts against it under the influence of passions. Aristotle does not determine whether the incontinent elects something in acting incontinently. Aquinas's treatment of incontinence adds two elements to Aristotle's account. First, the incontinent person chooses to follow the passions, thus they sin “choosing,” though not “from choice.” Second, he holds that incontinent person consents to the incontinent action.

Christian Schäfer, “Von Augustinus zu Johannes Damascenus: Das Problem der unausgesprochenen Willensschwäche bei den christlichen Neuplatonikern,” pp. 59–87: Augustine, Dionysius Areopagita and John Damascene are more interested in the phenomenon of willing evil than in that of weakness of will. Yet their writings contain unmistakable allusions and surprising solutions to the problem of weakness of will, although these differ from the standard Aristotelian account of akrasia. I interpret their tenets on weakness of will according to the fundamental idea of a moral privatio boni debiti ("privation of the good that is owed"). It may also be seen, according to the Neoplatonic tradition, as a momentary failure to achieve what one's own nature proposes and defines to be best.

Bernd Goebel, “Anselm von Canterbury über Willensstärke und Willensschwäche,” pp. 89–121: This article explores two things: first, Anselm of Canterbury's analysis of how precisely weakness of will is conceivable; and second, his doctrine of free will, by which he shows how it is possible either to succumb to weakness of will or to avoid it. Throughout, he distinguishes clearly between the will of morally bad and of good persons. With regard to the first, he accounts for weakness of will within an intellectualist and determinist framework. Conversely, he explains that of good persons in terms of voluntarism and indeterminism. Yet the voluntarist account risks collapse into pure intellectualism.

Jörn Müller, “Das Problem der Willensschwäche bei Petrus Abaelardus,” pp. 123–45: This paper argues that the phenomenon of weakness of will is central in Peter Abelard's writings. An analysis of his notion of the will and of willing, with special emphasis on Abelard's concept of consent, reveals that he distinguishes between weakness of will as a special type of action and as the disposition which makes this kind of action possible. Furthermore Abelard develops two different models of the phenomenon: in one case, there occurs a break between rational judgement and willing (motivational weakness of will); in the other the connection between willing and action is ruptured (executive weakness of will).

Christian Trottmann, “Bernard de Clairvaux sur la faiblesse de la volonté et la duperie de soi,” pp. 147–72: Bernard of Clairvaux, probably the first author to use the term infirmitas voluntatis, does not identify weakness of will with reluctant action. Even in case of weakness of will, one maintains free will. Bernard gives the example of Peter denying Christ on Good Friday. He wants to be faithful to Christ and he wants to save his life, but he is self-deceived with regard to the order of his preference, and he freely consents to lie. Bernard's analysis is quite different from those of Anselm and Abelard but very modern, when it is seen in light of Donald Davidson's.

Alexander Fidora, “Die Behandlung der Unbeherrschtheit in der Summa Alexandrinorum,” pp. 173–95: This paper discusses the account of incontinence (akrasia) given in the Summa Alexandrinorum, an influential ethical compendium translated into Latin in the 13th century by Herman the German. Two different approaches to the problem are identified. One highlights a lack of reason and a lack of experience. This seems to be the Summa 's original contribution to the problem. The other displays a theory of ethically qualified consent. It operates with a strong concept of free will. This may correspond to a later layer of the text. Moreover the paper suggests Nicolaus Damascenus as the possible author of the Summa.

Martin J. Tracey, “Albert on Incontinence, Continence, and Divine Virtue,” pp. 195-218: Does Albert the Great defend the possibility of incontinent action in an original way? I argue that he does, in Super Ethica 7.1-10. Albert's defense, unlike those of some modern action theorists, does not consist in a refinement of Aristotle's practical syllogism, but rather in an explanation of how an inferior power of soul, passion, is able to dominate a superior one, reason, in the incontinent act. Albert's defense of the possibility of incontinent action is subsumed within his effort to persuade Latin Christians of the truth, orderliness, and sufficiency of Aristotle's moral philosophy.

Tobias Hoffmann, “Aquinas on the Moral Progress of the Weak Willed,” pp. 221–47: The paper investigates Aquinas's explanation of how the incontinent can make moral progress. The incontinent cannot be healed by moral instruction, because they already know what is best, but fail to act accordingly. Their moral knowledge has to be interiorized. Thus by attaining prudence and the moral virtues, moral knowledge becomes practically effective knowledge. Yet these virtues are no remedy for the incontinent, who is still struggling to attain them. By reason and will they can resist individual acts of incontinence, but in order to resist incontinence consistently, they need the assistance of grace.

Theo Kobusch, “Willensschwäche und Selbstbestimmung des Willens: Zur Kritik am abendländischen Intellektualismus bei Heinrich von Gent und in der franziskanischen Philosophie,” pp. 249–63: This paper delineates the conflicting understandings of weakness of the will at the end of the 13th century. One account is presented by the ‘intellectualists' who stick to the Aristotelian idea that weakness of will has its origin in the clouding and error of reason. In contrast, their ‘voluntarist' opponents stress the primacy of the will; weak-willed actions can occur only if the will freely gives in to desire. Their discussion of this topic is embedded in an extensive debate about the self-determination of the will and the hierarchical order of reason and will within the human soul.

Alexander Brungs, “Intellekt, Wille und Willensschwäche im Korrektorienstreit: Einheit des Menschen vs. Homunculi,” pp. 265–83: In his Correctorium fratris Thomae, the Franciscan William of Mare takes issue with Thomas's claim that human beings are free because they can deliberate about their actions. Thomas's view seems to entail that a person who acts without deliberating is not free. William's Correctorium provoked a number of reactions from Dominican friars, such as Richard Knapwell, John Quidort, and Robert Orford. These intellectualist thinkers tend to stress the unity of the human person who thinks and wills, while William and other voluntarist thinkers tend to talk of the faculties of the soul as though they were themselves free agents.

Timothy B. Noone, “Duns Scotus on Incontinentia,” pp. 285–305: A protracted discussion of incontinentia is absent in the Scotistic corpus. Scotus radicalizes the independence of intellect and will. In his view, the possibility to act against the better judgment is inherent to the will, and thus there is no necessity to investigate any conditions for it. He does however repeatedly discuss the moral psychology of a person acting against better knowledge in contexts such as the metaphysics of willing, the roles of knowledge and will in action, the nature of the virtues and their connections, and human and angelic sin.

Matthias Perkams, “Der schwache Wille: Ockhams Theorie der Unbestimmtheit des Willens als Auseinandersetzung mit dem Problem der Willensschwäche,” pp. 307–29: It seems that for Ockham, the concept of incontinence obsolete, since he holds that the will is always free to deviate from one's rational judgment. This supposition is wrong. According to Ockham, the free will usually follows the rational judgment. Its failing to do so manifests the weakness of the will as a power of the soul. For in order to be in accordance with practical reason it must be determined by an object and a habitus. Ockham's theory of virtue can be understood as an attempt to explain this in more detail and to account for its possible remedies.

Risto Saarinen, “Weakness of Will in the Renaissance and the Reformation,” pp. 331–53: The early modern discussion on Aristotle's akrasia, weakness of will, was closely related to the interplay of the will and the passions. The innovation of early modern Ethics commentaries, i.e. to present concrete examples of akratic behavior, contributed to the emergence of some non-Aristotelian features. New paradigmatic cases were the original sin of Adam and Eve and the rage of Medea. The case of Medea is of particular interest, because it portrays a non-Aristotelian, clear-eyed akrasia. For Protestant thinkers, this view of clear-eyed akrasia was appealing because it highlights the general tension between sinful passions and moral awareness.