Abelard in Four Dimensions is an excellent introduction to the study of Peter Abelard. The "four dimensions" in the title refer to future, past, and present--Abelard's and our own. The book begins with Abelard's present: Chapter 1 is a very helpful discussion of the current scholarly controversies on the chronology of his works, in the face of Peter King's suggestion that the chronology is "largely obscure." Marenbon's conclusions are summarized in the section of his bibliography that lists editions of Abelard's works. Though listed alphabetically, not chronologically, the reader will find the dates Marenbon suggests in parentheses after the title of each work for which a date is indicated.
The main part of the book is unified by its focus on a characteristic and controversial argument which concludes that God cannot do otherwise than he does, abbreviated NAG: no alternatives for God. Accordingly, Part I, Chapter 2 presents this argument and its reception by Abelard’s contemporaries, and a defense of its sophisticated reply to objections such as the claim that his view entails that God cannot saved the damned--that is, since God is just, he cannot save the damned, seemingly a restriction on God's power. Marenbon tells us that it is not true that Abelard holds that the damned cannot be saved, given the distinction between the possibility of the antecedent used referentially to pick out the damned and the possibility of the consequent. Put in simpler terms, Abelard affirms that a sinner can be saved, in that she can lead a life worthy of salvation, but if she chooses not to do so, God will damn her. God cannot but choose the best course of action. But human consent is free, and if it is exercised for the good, humans can and will receive justice from God if that is acting for the best.
The second part of the book is devoted to Abelard's past and future: Chapter 3 asks about Anselm's influence. As Marenbon points out there is evidence that Abelard knew Anselm including verbal parallels between Anselm's Monologion and Abelard's Dialogus. Marenbon also shows that both men agree about the famous case in which a person lies or kills in order to escape their own imminent death. Verbally, they disagree, since Anselm affirms that the person wills the action, while Abelard holds she does not; more properly she suffers it. Nonetheless, Abelard agrees with Anselm that the person is culpable since she consents to act, albeit unwillingly. Marenbon says in conclusion that Abelard knew Anselm but was not concerned "to gain an accurate and full knowledge" of his ideas.
Chapter 4 is devoted to the many philosopher-theologians who failed to appreciate or simply misunderstood Abelard's NAG thesis, from Peter Lombard to Leibnez. Thomas Aquinas figures in this narrative as the one philosopher-theologian who took the central claim of NAG seriously. But fittingly Lombard gets the most space, since his treatment is the most influential. Moreover, though Lombard does not present the strongest arguments for the position, he is right to say that, understood as most Christians would understand it, the claim that God only acts justly for the good does not entail NAG. Importantly, Marenbon notes that Lombard is not defending a voluntarist account of God and that much of his disagreement with Abelard is based on the different versions of the principle of sufficient reason they assume. For Lombard, we need not affirm that God performs only actions that are better than, but only that his acts are never worse than, any alternative.
The last part of the book (Chapters 5 and 6) considers Abelard in the context of contemporary theories of meaning and metaphysics. Chapter 5 considers Peter King's 1982 thesis that Abelard anticipated the views states by Hilary Putnam and Saul Kripke, in that Abelard "holds a theory of direct reference, in which the extension of a term is not a function of its sense," and hence persons imposing a term need not be aware of its "proper conceptual content" in order to name something properly. However, unlike Putnam and Kripke, Abelard assumes that our sense perceptions are accurate, and mental representation of the natural kinds of things we have experienced are reliable.
Chapter 6 considers the relation between Abelard's metaphysics and Trope Theory as espoused by D. C. Williams in 1953. Here Marenbon himself has made a major contribution to the debate, claiming that Abelardian forms are in some way like tropes. But Marenbon concludes that much of contemporary discussion misses the point of Abelard's thinking. As Marenbon points out, though Abelard affirms that fatherhood is not other than someone's being a father, he also holds that "fatherhood cannot simply be collapsed into the father."
In his conclusion Marenbon reflects intelligently on how best to bring medieval thinkers into the contemporary discussion: not by distortion, forcing medieval ideas into "a conceptual framework where they do not belong," but by asking ourselves not only how they resemble modern positions, but also how the problems addressed differ from those today's philosophers pose.
Myself, I found the book harder to read than necessary because its abbreviations are awkwardly sandwiched between the text and the notes, which appear not where they belong with the corresponding text, but at the back of the book. Nonetheless the author's research and reflections are richly rewarding.