^[1] What we might call the ‘philosophical theology’ of Gregory of Nyssa is a subject increasingly engaging the minds of theologians, philosophers, and historians of ideas. A number of recent studies and monographs have confirmed the tremendous insights that can be gained by reading Gregory of Nyssa with an eye to Classical philosophical traditions, and even to more theoretical philosophical concepts in general. What emerges is a Gregory far removed from the somewhat simplistic thinker formerly castigated by historians for his philosophical ineptitude. Turcescu’s book makes an important contribution to this new portrait of Gregory as a philosophically sophisticated and original theologian who developed new metaphysical ideas in the service of a fully Biblical theology. Published studies thus far have tended to focus on the notions of nature, substance, and universal in Gregory; Turcescu’s is the first to take the notion of person (correlative to those of nature, substance, and universal) as the main centre of attention. It is Turcescu’s contention that Gregory’s notion of person is original and far in advance of notions held by Gregory’s predecessors, whether theological or (more importantly) philosophical. To make this point, Turcescu’s first two chapters (around a third of the whole book) focus on relevant philosophical ideas in thinkers prior to Gregory, including not merely the whole philosophical tradition, but also theologians as close to him as his brother Basil of Caesarea. In order to get clear about just what exactly he wishes to speak, Turcescu starts with what he takes to be a good working definition of ‘person’ as ‘an indivisible, unique and therefore non-replicable unity in human existence’ (p. 7). The first two chapters then deal with a cluster of issues in ancient writers – individuality, the soul, the will, the possession of consciousness – in order to show that the accounts of all of these are relatively underdeveloped compared to the understanding of persons offered by Gregory of Nyssa. The remaining chapters deal separately with various relevant works of Gregory, focusing mainly on the standard technical ones, but also drawing briefly on Gregory’s writings on gender and on spirituality.

^[2] Unfortunately for all Turcescu’s attempt at clarity, it never becomes entirely clear just what question is being asked. For, as Turcescu’s discussion makes clear, the ancients have various notions more or less connected with that of person as defined by Turcescu. Thus Turcescu presents material not only on the individual (as composites of matter and particular form; as composites of matter and universal form; as collections of material properties unified by the presence of a soul), but also on the will and decision-making in general (including the necessary self-willing of the One in Plotinus), and on consciousness. As it turns out, not all of these are relevant to the discussion. Turcescu evidently sees the notions of the individual (as a collection of properties) and the will as somehow significant in Gregory’s development of the notion of the person. Neither discussion is developed very satisfactorily. Let me focus on the notion of the individual as a collection of properties.

^[3] Gregory, as is well-known, sees persons as collections of properties – thus positioning himself amongst the array of philosophical options open in antiquity. As Turcescu sees it, what Gregory adds to this, what makes Father, Son, and Spirit, persons as opposed to ‘mere’ collections of properties is the revolutionary notion of communion:

^[4] But there is a fundamental confusion here. For the question that Turcescu seems to deal with in chapter 2 is that of the explanation for the unity of a person. Collections might be no more than aggregates, and the unity of a person must surely be greater than that of (for example) a heap of stones, or of the aggregate that is me and the planet Jupiter. Appealing to the soul in this context (an appeal made by Plotinus) is a way of explaining how it is that a body is more than just a collection of properties: the body is a substantial unity, as it were, because the soul is a principle of unity constituting the body in such a way. Communion, as understood by Turcescu, seems to be a way of securing divine unity: that is to say, the unity between the different persons that constitutes them as one God. (Gregory, it seems to me, might think of communion as a necessary condition for divine unity, though I would be surprised if he thought of it as sufficient.) But this is a different question, and Turcescu, in making his claims for Gregory’s originality at this point, is not quite comparing like with like. Indeed, it might be thought that Plotinus has a firmer grasp (than either Gregory himself or Turcescu) of the philosophical requirements here, and a stronger sense of what is needed to supply substantial unity to a collection of properties. And substantial unity is exactly the sort of thing that a sophisticated and developed account of personhood requires.

^[5] In fact, it seems to me that the whole notion of individuality needs a far more refined treatment, both in the Classical philosophical tradition and in Gregory, than that which is provided here. For Classical philosophical notions of the individual are opposed to notions of division (diairesis): the individual is something that is a divided ‘part’ of a whole, and the point is that it is not itself divisible in whatever way the whole is divisible. Gregory rejects this notion, and it is in any case hard to see what role it could play in his thought, since for Gregory the divine nature (and for that matter any creaturely nature) is indivisible, and the persons not divided parts of it – points that Gregory makes very clearly in Ad Ablabium. There are other less technical philosophical notions that Gregory uses in place of the notion of the individual – to kath’hekaston, for example. Except for a couple of brief passages in Ad Graecos Gregory does not use more technical terms for the individual (for example, merike ousia – partial substance or particular substance). As it happens, in Ad Graecos Gregory argues from ‘notions common’ to contemporary philosophers, and it seems to me that he makes fleeting and reluctant use of a philosophical notion fundamentally alien to his own thought patterns. Turcescu notices the oddity of Gregory’s usage here (see his discussion on p. 70), though does not, I think, alight on the correct diagnosis – namely, that the whole notion of divisibility is alien to Gregory’s theory of common natures or universals. Turcescu never sorts any of this out, and so it remains fundamentally unclear which classical notions he sees Gregory as improving on. It also means that a considerable portion of Turcescu’s discussion of the classical background turns out to be irrelevant, for whichever classical notion Gregory’s understanding of person draws on, it is not that of the individual, at least if understood in the technical metaphysical sense just outlined. For what it is worth, it seems to me that Gregory’s notion of the universal is of an indivisible but immanent shared property, and that the correlative notion of the person is of something that is made up of various such universal properties. What the principle of unity within any given person is remains somewhat mysterious; Gregory’s innovation lies in the stipulation of immanent universals, not in any explanation for the numerical unity of any such person.

^[6] None of this belittles the huge philosophical originality of Gregory himself. But it is to suggest that for all the interest of Turcescu’s book, it cannot constitute anything like the final word on its subject. If I were to suggest one of a number of possible fruitful ways forward, it might be to focus on the notion of activity in Gregory (unified in the divine persons; distinct in non-divine persons). After all, the notion of agency is central to many modern accounts of person. Discerning ways in which hypostases do not have to be distinct agents might go a long way towards clarifying the ways in which Gregory understands the notion of hypostasis/person.