The conceptual history of Christian love is a much-debated subject. Scholars and church leaders from the Swedish Lutheran Anders Nygren (Eros och agape, 1930) to the present pope Benedict XVI (encyclical letter Deus caritas est, 2005) have frequently stated their expert opinion on this matter. Thomas M. Osborne sets out to study the notion of natural love in two classical scholastic theologians, Thomas Aquinas and John Duns Scotus. Since a vast secondary literature already exists pertaining to this topic, the reader may wonder why another study would be necessary.
But Osborne's book, originally a dissertation at Duke University, manages to convince the reader of the usefulness of its purpose. Already in the introductory part the author explains patiently and carefully in which ways the medieval philosophers and theologians deviated from both Aristotle and the modern thinkers. Osborne pays a great deal of attention to the connection between the common good and the agent's own good in medieval teleological thinking. Although the two ends can be conceptually distinguished from one another, the medievals normally thought, unlike modern philosophers, that a universally good action is also good for the agent.
If ethics is concerned with the person's own end, it also follows that a moral person cannot simply prefer another person's good instead of his or her own. Preferring another person's good would mean turning away from one's own end, a move which is considered to be sinful or at least less than good. Therefore, egoism and altruism do not exist in the modern sense of these words. Moreover, in order to further a common good in a non- sinful manner, one has to order one's own good as part of this common project. For a modern reader, this sounds like egoism, but a careful historical reader of the texts should not project the modern notions of egoism and altruism to the sources.
What happens when an adherent to this kind of Aristotelian or eudaimonist ethics interprets the biblical command to love God above all things? This is a major issue of Osborne's book. In the medieval paradigm, it is possible to love God in the supernatural manner, with the help of grace. But Osborne is interested in finding out whether for the medievals the natural love of God can supersede the project of furthering one's own good. The Aristotelian project seems to be at variance with the biblical command, and some medievals, for instance Henry of Ghent, indeed claim that the Aristotelian ethics is mistaken. Both Aquinas and Duns Scotus, however, hold that Aristotle's ethics can be reconciled with the duty to love God.
Aquinas thinks that everything by nature furthers the common good of the universe. This totality of the universe can, finally, be considered as equivalent with God. For Thomas, the Aristotelian idea of realizing one's own good is a partial aspect of this totality. Because of our fallen nature, we cannot, however, order ourselves according to this natural and created order. Given this, it is true for both Aquinas and Scotus that a person cannot prefer another person's good. But God is here the exception to the rule, since God is the common and universal good. Since the individual good is considered to be an aspect of this universal good, a person who loves God above all things also loves himself in the manner which optimally furthers his own good. In this way, preferring God's good also optimally furthers one's own good.
The medieval argumentation is not always obvious or convincing for the modern reader. Osborne deserves high credit for his clear and patient style which guides the non-specialist reader into the forgotten ideas and patterns of thought. Maybe the author sometimes exaggerates the differences between various periods of history. He holds, for instance, that modern scholars cannot read even Aristotle himself properly unless they take the medieval paradigm into account, for many tacit assumptions which influence our judgments stem from the medieval period. This may be the case, but one can nevertheless argue that a competent scholar can gradually liberate himself or herself from such assumptions through a careful study of the texts. In order to read historical texts in an adequate manner, it cannot be necessary to know everything between the period of their emergence and the present day. But this interpretative remark is a minor issue. It may be that Osborne's book has not much new to offer for the specialists in Aquinas and Duns Scotus, but his careful terminological guidance makes the book very valuable for all those non- specialists who are less aware of the terminological shifts of meaning.
As all historians of philosophy know, Thomas and Duns Scotus differ in their theory of will. But it is more difficult to define precisely how they actually differ. Osborne sees this difference in rather standard but nevertheless helpful and educational terms. Aquinas's concept of will appears to be rather Aristotelian and teleological. Scotus is not, however, presented as modern voluntarist. It is important to see that the will for Scotus is also a "rational appetite" directed towards the natural good. For Scotus the teleology of this will is twofold, since the will can either further its own good or that which is generally considered to be just. Osborne claims that this ambivalence of ends distinguishes Scotus's theory from the simple Aristotelian teleology and, in fact, already foreshadows the modern concept of volition.
Although I think that Osborne's view of the will in Thomas and Scotus is plausible, it can also be challenged and remains open for debate. Scotus's view is dependant on Augustine and especially Anselm of Canterbury. Thus it is not only innovative, but also very traditional. Thomas's view is not merely Aristotelian, but Aquinas also adopts many aspects of the Augustinian theory of will. With regard to the problems of natural love, however, I find that Osborne's understanding adequately captures the meaning of his sources.
Osborne's study is a highly readable and erudite work. Because of its clarity and awareness of the historical distance between medieval and modern thought, it can be fruitfully employed in the academic teaching of medieval philosophy and theology. The book is also a useful introduction to the subject of natural love for those scholars who have an interest towards later periods, for instance Renaissance and Reformation. The views on natural love, self-love and sacrificial love probably changed radically during these periods. Osborne's description of the medieval synthesis offers a reliable point of comparison.