This book is published as part of the series, ‘Oxford Philosophical Monographs’. It is to be welcomed together with other recent books from Oxford University Press which deal with Aquinas or medieval philosophy. As such, it is part of the current and rather unexpected growth of publications in the English-speaking world on medieval philosophy and medieval thought in general. This fact perhaps reflects more the interests of researchers than that of students. However, the wealth of recent introductions of the history of medieval philosophy, such as those of Kenny and Marenbon, will make sure that this extremely interesting era of human thought will not go unexamined by future undergraduates, as was done so often in the past.

Many of the recent books on medieval philosophy seem to reflect and present the fruits of individual research. This seems in large part due to the fact that those in search of an original research topic find the field of medieval thought to be extremely rich in hitherto unexamined sources. Again, it often happens that once the researcher begins to engage with a medieval author she find herself more often than not dealing with a professional philosopher or theologian who displays a rigour of thought which is so often lacking in more recent philosophy. This is a point which Schwartz elegantly makes in his Preface: ‘My own interest in Aquinas and in friendship developed gradually as I grew acquainted with his works. It was only when I managed to transcend my own prejudices about theology and scholastic philosophy that I became able to appreciate the beauty of Aquinas's thought, its breadth, rigour and depth’ (viii).

Schwartz's central contention is that Aquinas's notion of friendship is indeed a reworking of classical notions of friendship, especially that put forward by Aristotle. However, by seeking to situate such ideas with ideas which were important to his times, Aquinas succeeds in producing a theory of friendship which is more flexible and more accommodating to real human differences and disagreements than that proposed by Aristotle. Schwartz comments: ‘Aquinas's discussions of friendship remain exemplary in that they bear testimony to the efforts of a bright mind set on enriching and modifying Aristotelian friendship to suit the realities and intellectual and spiritual preoccupations of his own time’ (ix). Of course, much of Aquinas's thought was his own, but he also could make use of centuries of Christian reflection on friendship and love, influenced as these were in the beginnings by Stoicism and Neoplatonism, by patristic and biblical sources, and the reflections of those who sought to understand how ‘amor amicitiae’ could apply both to God and one's neighbour.

Schwartz tells us (ix) that the book is based on the dissertation which he wrote for his doctorate under the supervision of John Finnis, with some chapters being rewritten or added. In addition, the book draws upon material that has already been published in a number of well-known journals. The result of these origins is a book which is somewhat uneven in terms of delivery and presentation.

If I might put it this way, a book dealing with an author such as Aquinas needs to use both the telescope and the microscope: the telescope to enable us to see clearly something which is distant from us in both time and culture; the microscope to look at his intricate arguments in detail. The latter instrument is something which is apparent throughout the book and is what makes it an extremely valuable resource. We are ably guided through a very detailed examination of both the arguments and the works in which Aquinas put forward his views on friendship. However, the telescope is lacking. There is little concession to the general reader who may be unfamiliar with the particular type of scholastic disputes being presented. Although there are some references to later scholasticism such as to the ideas of Duns Scotus, de Vitoria, Suarez or disputes at the times of the Reformation, these are few and far between. The reader is also presumed to have a good working knowledge of the authors used by Aquinas, such as Augustine or Gregory the Great. In other words, the book is one for the specialist rather than the general reader.

Again, the author is so concerned with giving a faithful analysis of Aquinas's texts and arguments that it is rare that he speaks with his own voice. I think that this is a shame because much of what Schwartz has to say would, if translated into a contemporary idiom, be of great value to many of the debates which touch upon the nature of society and the ties which bind us together. The arguments of Aquinas not only provide us with an analysis of what may be wrong with contemporary society, but also provide us with many ways of thinking our way out of such problems and suggest practical ways in which this might be achieved. It is to be hoped that the author will, having completed his magnum opus, now turn to the divulgation of his results in a more user-friendly form since what has put together here is of great value.

Attention needs to be drawn to a problem with the method employed rather than mere presentation. In the medieval university, given the absence of the teaching of philosophy in the higher faculties, much of the higher-level work was done by theologians. These often mixed philosophy and theology together while, for the most part, recognizing the distinction and autonomy between the two disciplines. It can be a problem for a modern researcher, when following the thread of an argument, to know when to stop. If I begin by looking, for example, at time, motion, and infinity in a thirteenth-century author, at what point does the argument stop being philosophy and start becoming theology? Aquinas himself was quite clear on the matter: those ideas which are revealed and could not be known by human reason unaided are not the business of philosophy. Thus, I would contend that Aquinas's comments on Christology, although of interest and showing his use of philosophical ideas in theology, are not, in fact, philosophy and the reader should be alerted to this fact.

Schwartz's careful research into all aspects of Aquinas's thoughts on friendship and his analysis and documentation of sources means that this book is one which will be consulted by many in the coming years as a place from which to begin. What this reader found most interesting was not Aquinas's restating of much of the ancient and Christian thoughts on friendship but the context of the discussion and the ideas which Aquinas felt were connected with friendship theory. In this respect the book opens up vistas which are not normally associated with discussions of friendship and which should be further developed in the future. This can perhaps become clear by taking some examples.

Having stated that, for Aquinas, love is the cornerstone of human behaviour, the motivating factor which lies at the root of all of our actions (24), Schwartz comments that what happens between friends can be explained by examining the kind of love which keeps them together. But now another matter for reflection arises: can friendship survive disagreement? Can we be friends with those with whom we disagree over fundamental issues such as religious belief? As Schwartz points out (34) Aquinas held that it was not possible to be friends with heretics: ‘Anyone who from among the many things taught by the Church holds those he likes and does not hold the ones he dislikes, no longer holds fast to Church teachings as an infallible rule, but to his own will’ (Summa Theologiae, 2a2ae, q. 5, a. 3 c.). The heretic is a source of discord because of his or her sin of pride; religious and political factionalism are due to the disunion of wills: ‘Now if a man's will holds fast to his own, this is due to the fact that he prefers things that are his to things that are others’ and if he does this inordinately, it is due to pride and vainglory' (Summa Theologiae, 2a2ae, q. 37, a. 2 c.). Aquinas compares the situation to that of a student who rebels against his teacher; the student is declaring himself to be self-sufficient, to be able to pick and choose what he or she wishes and so ends friendship with the teacher by becoming incapable of being taught.

In adapting Aristotle's ideas on friendship into a Christian framework, Aquinas was often faced by difficulties. Aristotle held that there could not be friendship between those who are unequal since they have little in common. How then can human beings be friends with God? Indeed, how can we be friends with someone who has determined that we shall suffer and die? Friendship with God, it seems, would require us to will the evil which God imposes upon us (51). The manner in which Aquinas resolves this question is one of the high points of Christian theodicy and is fully explored by the author in chapter 3.

Aquinas was well aware of the fact that there are some people who prefer to sow discord rather than to accept as Aquinas did (following the Stoics and Cicero) that all human beings are friends of each other. At the root of this is an attitude which refuses conformity of wills, an unwillingness to join with others which is identified with superbia, arrogance or unreasonable pride (69). Aquinas's condemnation of schism and sedition derives from his appreciation of the positive good of the unity of any community. For this community to survive, agreement is necessary; people must choose to will what others will. Some people, however, refuse to do so by simply choosing to disagree. Aquinas is not, of course, condemning originality, conscience, or the intrinsic worth of each human individual. What he does condemn is an irrational attitude which refuses to agree with others, either out of an exaggerated sense of one's own worth or due to self-delusion. He also points to the fact that some people will sow discord and divide one person from another in order to achieve long-term goals of their own. It is not just a matter of selfishness; it also involves the delusion that one can satisfy ones own needs by deceiving others.

Pride is a barrier to friendship because it runs counter to the injunction of the Delphic oracle that we must ‘know ourselves’. The proud person does not know who she or he really is. Schwartz is to be praised for demonstrating how Aquinas's ethical theory can be sophisticated and comprehensive while at the same being direct and commonsensical. One is struck by how good a guide Aquinas is as regards how to live well, in the truth and in the absence of self-delusion. Friendship, which many consider to be some kind of exclusive relationship between two individuals (and to the exclusion of all others), here becomes the prerequisite for any community. It is the key to understanding how people can come together and live and work together; it is also the key to analysing what may go wrong in a society and how a solution may be found. Concord, the decision to will what others will, to have a correct assessment of ones own strengths and weaknesses, to accept guidance from others when necessary, in other words, all that friendship teaches, is the prerequisite for a social bond and a solution to social disintegration. The importance of Aquinas for the history of thought is that he places friendship within the context of the totality of social relationships and thereby avoids the notion that friendship is exclusive.

Aquinas is optimistic that we can learn from our mistakes, that we can turn away from self-delusion, that discord in a community can turn to agreement. The problem remains that some people can persist in thinking that they are self-sufficient, that they do not need friendship with their fellow man or with God. Schwartz gives a crucial quotation on 92:

In other words, experience will ultimately show a human being that his self-assessment of his own self-sufficiency is false.

Aquinas was certainly no naïve idealist where human relations were concerned but neither was he unduly pessimistic or cynical about the possibility that we can, in fact, be good. In chapter 5, the problem of the possibility of trust in human relations is examined. Trust is based upon the confidence that we know something or someone, yet do we ever really know what lies at the heart of another human being? Despite the uncertainly which one may have about the present or future intentions of another person, Aquinas argues that ‘the good is to be presumed of everyone until the contrary is proved’. This, of course, is not unconditional but involves prudence and the avoidance of credulity. On 105, we have a very sharp phenomenological description by Aquinas of the person who thinks ill of others.

The saintly Jeremy Taylor, in the course of his response to the redoubtable Katherine Philips, is regarded by many as the first to admit that there can be true friendship between a man and a woman. Previous theories of friendship had ruled out the possibility because of the inequality in station between the two sexes, or indeed because of sex itself. Thus, Aquinas's treatment of matrimony as a form of friendship (98) is especially interesting. For Aquinas, marriage is a unique form of friendship in three respects: (a) it is for procreation, the education of offspring and the setting up of a domestic life, (b) it is a lasting bond, and (c) unlike other friendships, it is a sacrament, that is, a way of becoming holy (98n.).

The role of hope in friendship is perhaps often passed over but it is regarded by Aquinas as a prerequisite for all social relations (108). It enables us to face the difficulty of working together with people through not despairing of its impossibility. No individual or collective enterprise will be engaged upon without hope and social cohesion cannot be sustained in the face of despair. Without hope we do not extend friendship to others nor think that we can co-operate with someone else.

Chapter 6 again brings us into somewhat unusual territory for friendship theory: should friends bring their disputes before a third party and, in particular, before a judge? The origin of the problem was the experience of the early Church. For its members the Church is a community based on friendship. This, however, does not exclude the possibility that disputes can arise, and so one must face the problem as to how these are to be dealt with. Some disputes are so serious that they cannot be resolved amicably and one has to have recourse to the courts. Friendship must be based on justice as well as truth. One cannot forsake justice simply to keep the peace, a peace which may, in fact, be a false one. As Schwartz comments (140), this tension between a concern for peace and the pursuit of legitimate rights remains problematic for Christians, from the supporters of liberation theology in Latin America to the role of the churches in the conflict in Northern Ireland.

Chapter 7 deals with how to re-establish the bonds of friendship and the roles of reconciliation and reparation. Much of what Aquinas writes on the topic has to deal with soteriology and the sacrament of penance. Some general principles emerge which can be applied to human relationships as well. Reconciliation involves not just the admission of wrongdoing but the attempt to restore the honour or dignity to the victim by the wrongdoer. Public repentance is important (and medieval society was rich in rituals of penitence) because if unlawful acts are allowed to be perpetrated against an individual or a class of individuals (one thinks of attacks on the elderly), then the perception will arise that such persons are not owed respect. As Schwartz comments (151), offenders must acknowledge the dignity of their victims so as to restore their honour and status within the community.

In the final chapter 8, ‘Concluding remarks’, the author makes some brief statements regarding his central thesis: that Aquinas has broadened Aristotle's notion of friendship. It is the shortest of all of the chapters (barely three pages) and one which needs to be expanded further. It sketches out what I hope the author will go on to develop in subsequent writings. He comments (163) that Aquinas's treatment is versatile enough to accommodate the friendship relationships which Aristotle's theory could not, and is able to analyse and work out solutions for conflicts and misunderstandings. The author has succeeded in showing this in the course of the book, but here was surely the place to bring the fruits of this research together. I remain puzzled as to why the author thought it necessary to finish with an appendix on ‘The duality of the rational volition in Christ's human nature and friendship with God’. Some gentle advice regarding this and the conclusion could and perhaps should have been offered to the author.

The book contains a useful bibliography of both primary and secondary sources. There are three indices: an index locorum, index of subjects, and an index of names and places.