Pp. xvi, 408 , Cambridge University Press , 2005 , $35.00.

One of the difficulties for students of Scotus is the complexity surrounding his life and texts. We know relatively little about his tragically short life and the little we do know is shrouded in confusion and controversy at almost every point. Scotus' writings are amongst the most complex philosophical writings to be found in the medieval period and they require careful and sometimes patient analysis to get to grips with his thought. To make the matter of interpretation harder, Scotus seems to have been constantly revising his writings so that there are multiple versions of some of his texts and it is sometimes far from clear which represents his most mature thought on an issue. And, as if all this was not enough, potential students of Scotus need to bear in mind that some of his texts exist only in Latin, uncritical editions of the Latin at that, full of copyists mistakes and accidental additions to the texts.

With all of these barriers to understanding Scotus it is not surprising that he has been relatively neglected in comparison to writers such as Thomas Aquinas. This companion volume is therefore much to be welcomed as it provides some essential keys that start to unlock Scotus' thought and make him genuinely more accessible to English speaking students.

In the first place the volume provides a helpful introduction to Scotus' life and texts, providing a helpful chronology of the texts and flagging up the problems and uncertainties. A list of Scotus' writings which are available in English is provided, as is a broad 17 page bibliography on Scotus and his works. The twelve essays themselves provide a good balanced introduction to the breadth of Scotus' thought, written by leading figures in their fields they encompass: Metaphysics, Space & Time, Individuation, Modal Theory, Philosophy of Language, Natural Theology, Knowledge of God, Philosophy of Mind, Cognition, Natural Law, Metaethics and Virtue theory.

One of the limitations of studies of medieval thought is that sometimes writers will content themselves with merely summarising a text or argument. The more useful and more sophisticated studies set figures, and their texts, in their historical context, explaining both what they actually say and the significance of their views by showing how they differ from, and develop, the thought of previous writers.

Generally the essays in this volume are examples of the more sophisticated, and ultimately, more useful analysis. Dominik Perler's examination of Scotus' Philosphy of Language, for example, explains what Scotus says and then sets Scotus clearly in his historical context, showing how what he said differs from contempories and predecessors such as Boethius of Dacia, Siger of Brabant and Thomas Aquinas. This is helpful as the reader comes to appreciate not only what Scotus was saying but also why he felt that he needed to express himself as he does.

Less effective is the discussion of Space and Time by Neil Lewis, which mainly summarises Scotus' views and seeks to explain them. The few references to other medieval figures are largely triggered by Scotus' own comments and references. Scotus' views on time are definitely interesting but they are not necessarily the ‘radical modification of Aristotle's physical theory’ (89) which they are portrayed as, for they largely follow and build upon thoughts to be found in the writings of figures during the preceding 1/2 century.

Lewis begins his account of time with Scotus' discussion of the present instant and the paradox which Aristotle noted in his Physics. Aristotle sums up the problem tersely. We all think that time exists but the only element of time that ever seems to exist is the present instant. Now an instant has no extension and time does have extension, so it would seem that time actually never exists at all. Scotus struggles with this problem, as did generations of thinkers before him. In the later part of the twelfth century Albert the Great and Kilwardby had flirted with an explanation which identified the key element as the temporal relations which inhered in the present instant, thus giving a form of relational existence to time in the present instant. One of the problems in their accounts had been a tendency to confuse their philosophical language about temporal relations with a more figurative talk of the present instant ‘flowing.’ One of the questions to be probed in Scotus' account is whether he has managed to disengage the issues of relationality and flow so that he can move the discussion on. Lewis hints at insights and movement but because the discussion of Scotus is not set in its historical context it never gets to a clear conclusion about how he is differing from his immediate predecessors and why he is taking the approach that he is.

A key area in which Lewis identifies Scotus' radicalism is in the way Scotus is supposed to have undermined Aristotles' belief in the essential relationship between time and motion. It is true that linguistically he pushes at boundaries, but the key insights underlying the language belong to the previous generation of philosophers and theologians. Bonaventure, writing almost half a century earlier, had already pushed his Franciscan colleagues to imagine the relationship between time and the Primum Mobile (heavens) as contingent. The issue was clearly causing controversy at the time of the 1277 condemnation as one of the theses condemned was that there is no such thing as the aevum, a duration which measures the angels but which is not related to change or motion. The fact that theologians such as Robert Kilwardby were happy to talk of a changeless immutable God as existing ‘in’ time shows furthermore that the essential link between time and change was already being subtly questioned.

Lewis draws attention to Scotus' discussion of ‘potential time’ existing in the absence of motion, but again this is not as distinctive as it might at first seem. During the preceding fifty years thinkers such as Thomas Aquinas had already been exploring the idea of a matter and form of time, where time existing ‘materially’ was a kind of potential time, or a time with only some of its properties. What was unclear in the earlier discussions is whether the reason why time was thought to exist incompletely was because the absence of motion was taken as entailing the absence of a metric, or was the absence of motion thought to destroy the very topological structure of time. There are tantalising texts in several figures which suggest either or both interpretations. As twelfth century figures were largely unable to distinguish between the metric and topology of time they found it extremely difficult to address this question. One of the key questions which needs to be put to Scotus is where he stands in this debate. Is potential time to be thought of as potential because the absence of motion means that it has no metric or is it's status as potential arising because the absence of motion means that there is no substance in which the temporal relations can inhere and thus acquire their relational existence. Scotus has something to contribute to this debate but because he is not being set closely enough in the context of his period, the significance of his insights and comments tend to be somewhat blunted.

This Companion To Duns Scotus is nevertheless a useful and valuable tool for students of Scotus' thought. The complexity of the subject matter varies considerably between articles, meaning that although there are some articles which are accessible to undergraduates some of the material would find a more natural home with postgraduate students.