Now, Maurer's book isn't a replacement for or a competitor to Marilyn Adams' William Ockham, which must be one of the most impressive books on mediaeval philosophy of the last fifty years. At almost 1,400 pages, Adams' book is more than twice the length of Maurer's; it's enormously detailed and enormously comprehensive; it treats a vast range of arguments in precise detail, not only Ockham's, but those of many of Ockham's interlocutors and influences, including Aquinas, Henry of Ghent, Scotus, Chatton, Aureol, etc. Anyone who wants a good introduction to post-Thomistic philosophy and doesn't need it gentle would do well to study Adams' book carefully, together with John Wippel's The Metaphysical Thought of Godfrey of Fontaines: A Study in Late Thirteenth-Century Philosophy. (By the way, as long as I'm throwing out generalized recommendations, if you'd like to round out your education, gentle reader, you should pair these books with John F. Quinn's massive The Historical Constitution of Bonaventure's Philosophy, which is however unfortunately very difficult to obtain. I don't have a copy, but I worked my way through it while writing the old dissertation.)
There are, however, problems with Adams' book. For one thing, did I mention that it's freakin' huge? It takes some real stamina. I'll admit that I didn't finish it. When I was taking Timothy Noone's course on Ockham in grad school I started reading it, but about two-thirds in to the book and the semester, I stopped. It's not just the size, but the size combined with the presentation. Adams writes the kind of anglo-analytic scholastic stuff that I've never found very palatable, medieval arguments presented with a heavy 20th century veneer: lists of numbered propositions and labelled arguments, variables with subscripts and superscripts, occasional modern notation, etc. This is not necessarily bad in principle: Scotus himself used some of these techniques (he and Ockham have good claims to be the first real anglo-analytic philosophers, if the term implies an English-speaking origin, preoccupation with logic, linguistic analysis, a highly compressed (for Scotus) or lucid (for Ockham) style as opposed to a florid or elaborate one (like Henry's or Bonaventure's)), apparently for his own convenience, since it does not make him easier to read. But Adams uses them, presumably, for the convenience of and to appeal to a mid-20th-century mainstream analytic audience. This limits the book in some ways, since for a broader audience, continentals or people like me who are actually more familiar with the scholastic tradition than the 20th-century one, understanding Ockham through Adams sometimes means having to mentally re-translate her modernizations back into something like what Ockham might have really said. It's a little like a Latin trying to read Aristotle as translated and commented on by the Arabs - much better than nothing, for sure, but of course you'd rather have it straight from the Greek. And it's a real question whether the mainstream analytic tradition, not used to thinking in medieval patterns, will care enough about any scholastic thinker to master a book like Adams'. I'm afraid the whole Adams-Stump-Kretzmann-Kenny etc. project of dragging medieval philosophy into the mid-20th-century has been more or less a failure, given the fact that contemporary philosophy has moved on without really assimilating their work, making their books targeted at an audience that is fast ceasing to exist and so dated in a way that many books by the likes of Gilson or Maritain or Yves Simon aren't.
In any case, I was talking about Maurer. His book on Ockham may be no substitute for Adams', but in many ways I'm liking it better. It's extremely well written, very clear and even enjoyable. There's a huge amount of erudition behind it - Maurer has clearly mastered the corpus of Ockham's writings and the secondary literature - but I find the presentation clean, uncluttered, and very intelligible. Maurer's writing in English but he presents Ockham as a medieval, not as a modern anglo-philosopher in disguise. He's light on his feet, which is a pleasing contrast to some other scholars whose projects are similar. I'm thinking for instance of Wippel, whom respect and filial piety (he was one of my teachers and on my dissertation committee) forbid me to criticize too harshly. His (fairly few) books are magisterial and indispensable. But The Metaphysical Thought of Thomas Aquinas: From Finite Being to Uncreated Being is not exactly fun to read.
Maurer is not writing a really comprehensive survey, but as his title indicates, is seeking to understand the various facets of Ockham's thought as reflected in his few basic principles. The first part of the book treats these principles in themselves, with two long chapters on "Logic and Reality" and "Philosophy and Theology" which provide a very good summation of the central stances of Ockhamism. The second and third parts are about the application of these principles to God and Creatures respectively. Maurer presents Ockham without espousing Ockhamism, as he indicates in his introduction, but extremely fairly and straightforwardly, with only the very occasional criticism or caveat.
I'll post a longish excerpt soon, but right now I want to notice something Maurer says in the prefatory blurb right at the beginning of the book:
Martin Heidegger once declared, "Every thinker thinks but one single thought." The original and focal point of Ockham's thought is the singular or individual thing (res singularis), as common nature (natura communis) is the central conception of Scotism and the act of existing (esse) is of Thomism. With Ockham the traditional conjugations of being come to signify the thing itself in its ineluctable unity.
With all due respect to Heidegger, I'm not so sure about this. No doubt some thinkers can be reduced to one single central thought, but I have my doubts about both Aquinas and Scotus. Certainly some modern Thomists have acted as though all of Thomism depended on his doctrine of esse, but there's a lot more to Thomas himself than that. In fact when I think of Thomas what primarily strikes me is a certain kind of order which sets him apart from his competitors (recall his remarks about order in the first chapter of Summa contra gentiles). St Bonaventure is another extremely orderly thinker, but Bonaventure's sense of order is artistic and graceful, where Thomas' is schematic and pedagogical. Not for nothing is Thomas the patron of teachers. He excels at being able to talk intelligently about everything, and above all to produce the sense that everything fits. This is why Thomism gets compared to a Gothic cathedral. It's huge, it's varied, the variety is subordinated to a single great design. On the other hand the range of issues that Scotus or Bonaventure deal with is more restricted. Bonaventureanism is less like a cathedral and more like a fantastically illuminated manuscript.
It's more fair, however, to say that esse is an "original and focal point" for Thomas than it is to say that the common nature is for Scotus. That just strikes me as wrong. Scotus' mind does not evince either Bonaventurean or Thomistic order: opening his books frequently produces the sensation of falling into a profound but chaotic abyss of insight. His method is not systematic and his thought is not easily systematizable. Vos' book The Philosophy of John Duns Scotus tries to reduce it to some semblance of order by orienting his achievement around some central conceptual accomplishments, like synchronic contingency, but with in my opinion very limited success. The common nature is, of course, very important for Scotus, but the notion of the irreducible individual is no less so - in fact the Scotist insistence on the primacy of the individual is in my opinion one of its great strengths over Thomism. Haecceities, the formal distinction, intrinsic modes, essentially ordered causes, and many other distinctively Scotist ideas work together in a complex and delicate balance in which no one of them takes priority over the others and all are fitted into a more general Aristotelean substrate from which they only emerge as needed in the particular instance. There are certain basic Thomistic notions which Aquinas deploys over and over again in a hundred contexts with almost monotonous regularity - esse, the real distinction of being and essence, immateriality or separability from matter, etc. - in a way that Scotus doesn't. If Thomas' thought is like a cathedral, Scotus' is like a piece of enormously complex polyphony sung over a drone of Aristotelianism and a cantus firmus of revelation. You can't grasp it all at once because it's essentially developmental and progressive. You can't reduce it to a leitmotif because the various melodic themes arise when needed by the music as a whole in one or another voice, and the importance is less in any particular voice or theme than in their fugal interplay. What's happening now depends on what happened in the debate a moment ago more than on the demands of some architectonic conceptual structure.
All this rhapsodizing is, of course, taking us away from Ockham again. For Ockham I do think it's fair to say, as our own Ockham said the other day, "It seems Ockham took a handful [of] basic and already established principles then applied them relentlessly and consistently in places they had never been applied before." But if Ockham's strength is to show what happens when you join genius and fearless persistence to such a technique, damn the consequences, it would be a mistake to assume that other thinkers are trying less successfully to do the same thing.
As I noted, in a while I'll post a lengthy excerpt from Maurer's book. I may also say something soon about the other book I bought at the same time and am reading simultaneously with it, Sokolowski's Phenomenology of the Human Person, which I'm enjoying very much.