Facing the complex majesty of The Cloud of the Impossible, it is hard not to feel like some Moses-manqué before a literary Sinai. The prose is so finely wrought that any recapitulation risks flattening and collapsing what the text keeps folded and indeterminate. Sustaining a nuanced negotiation of ‘negative theology and planetary entanglement’, Keller's Cloud throws the reviewer back upon the classic apophatic dilemma of having to say something when the saying can only wreck what it says.

Catherine Keller is widely known as one of the most influential contemporary theologians. Her work spans a formidable range of disciplines, time periods, and locations, but it cycles back regularly – and always intensified – to the two pillars of her thinking: endings and beginnings. Twenty years ago, her Apocalypse Now and Then (1996) offered a feminist re-reading of the end-times forecast in the Book of Revelation, and subsequently exploited in service of variously disastrous political ends. Keller was attuned even then to the beginnings implicit in any possible or actual end; in the magisterial Face of the Deep (2003) she turned back to Genesis and a host of other myths, poems, practices, and sensibilities to unsettle the ‘dominological’ model of creation enshrined in the doctrine of creatio ex nihilo. Given its radical reimagining of ‘origins’ and its philo-poetic transformation of the whole genre, Face of the Deep is arguably the most significant work of theology to come along since Paul Tillich's Courage to Be.

While the years since Face of the Deep have seen Keller publish many books and edited volumes – most notably, the theo-political God and Power (2005); the meditative On the Mystery (2008); and the ground-breaking Polydoxy (2010) – it is clear that The Cloud of the Impossible is the next ‘big book’. Here, Keller moves from the figure of ‘the deep’ to the figure of ‘the cloud’, revealing a persistent folding-together – or entanglement – of creation and apocalypse, endings and beginnings, alpha and omega.

Throughout the book, Keller exhibits the qualities for which she has become best known: a steady interpretative generosity, an unrivalled ear for metaphor, and a tireless transdisciplinarity. In the Cloud (as in Face), ‘theology’ takes shape only as a complex interfolding of poetry, literary criticism, philosophy, physics, climate science, ethics, gender theory, sexuality studies, post-colonial critique, and critical race theory. This is theology faced with its limits and excesses – its vaulting historical failures; its phobias and anathemas; its constitutive relation to those ‘sciences’ of which it was once ‘queen’; its contemporary improbability; its over-proclaimed death and often awkward resurrections – and yet it is precisely at these limits and in these excesses that Keller finds the possibility of a transfigured, queerly chimerical discourse and practice, to which the Cloud gives the provisional name ‘apophatic entanglement’ (7).

This seemingly aporetic term is the book's central coinage; it is what the Cloud is ‘about’, and also what it does. ‘Apophatic entanglement’ is a way of thinking together two commonly opposed, even mutually exclusive, terms: the ‘apophatic’ all too often implying a mystical escape from the world, and the ‘relational’ usually resisting anything like secrecy or transcendence. The rift between the apophatic and the entangled can be seen in almost any corner of the theological, philosophical, or ethical playing-fields: those thinkers who get excited about negativity, uncertainty, and unsaying do not tend to remember issues like race, gender, and capitalism; while the authors most concerned with liberation and revolution tend to be suspicious of anything that looks like indeterminacy or unknowing. After all, the apophatic voyage as it tends to be recounted is one of progressive detachment: from material goods, political practices, family ties, sensual pleasures, intellectual aids, spiritual benefits, and finally one's own self, along with the ‘God’ for whom it conducted the journey in the first place. And so as the mystical not-I merges with the divine abyss, joining nothingness to nothingness, the ethically minded are compelled to ask, what kind of relation is this? And how could it possibly care about prison abolition, wind farms, or the minimum wage?

Such apophatic anti-relationality might in some sources be called politically useless. In others, it is politically disastrous. As Clement of Alexandria reminds us, Moses has to separate himself from the crowd in order to climb the mountain; there can be no illumination for the dark multitudes (Keller, 57). The works of Pseudo-Dionysius are similarly riddled with warnings that none of his teachings come within earshot of ‘the uninitiated’ or ‘the hoi polloi’. Such ochlophobia finds its crescendo in the Ecclesiastical Hierarchy, which charges deacons with the task of purging the church of those who are possessed, uninitiated, incompletely initiated, previously-initiated-but-now-degenerate, intemperate, intemperate-yet-resolved-not-to-be-intemperate, and finally, ‘those who . . . are neither completely unblemished nor completely unstained’ (3.3.7.436a–b). The masses must be expelled from the Mass, lest they profane the holy mysteries, clouding the ascent of the adept. What Keller intuits, however, is that such light-privilege and crowd-hatred are not inherent to the apophatic; more radically, they sabotage the unknowing they so regularly attend by foreclosing darkness and uncertainty. For Keller, such failures of negativity are the product not merely of ‘elitism’ or ‘ontotheology’, but of the whole world-view supporting the alleged escape from the world. In short, she suggests, classical apophatics has a cosmology problem.

According to the Aristotelian cosmology that structures most apophatic discourse, the earth occupies the heart of the universe, with concentric rings of water, air, fire, and sometimes aether around it. Divinity lies beyond this cosmic nesting-doll, binding its finitude with infinite power, benevolence, and cognition. The way to God, then, follows a straight line out of the universe: from material things (earth and water) to conceptual things (air, fire, and aether), to the no-thing that creates and eludes them all. Hence the strict ordering of naming and unnaming in Pseudo-Dionysius: the affirmations proceed from the godliest things (goodness, wisdom) to the ungodliest things (drunkard, stone), while the negations make their way back up and out of the world. Classical apophaticism does not, therefore, ignore relation so much as it instrumentalizes it, ordering earthly things into a static hierarchy in order to transcend the whole mess. Relation is necessary but penultimate, leading the soul into non-relational identity with the Great Neither-This-Nor-That. Nevertheless, as Derrida kept suggesting and un-suggesting, something about the via negativa threatens to unsettle the staid structure of the via; something about the cloud seems like it ought to entangle us with the crowd. And it is here that Keller's diagnostic powers are so acute: the problem, she suggests, is cosmic. Get rid of the nesting-dolls and the apophatic will actually be able to do the work of unworking, unknowing, disrupting, and remaking we keep wanting from it.

In so far as her ‘apophatic entanglement’ will require nothing short of a cosmological revolution, Keller signals that ‘the chiasmus of crowd and cloud will depend upon a Cusan crossing’ (48). It was Nicholas of Cusa, she reminds us, who first and most radically shattered the antique universe, taking the earth out of the centre well before Copernicus and replacing it with nothing – or anything, depending on your perspective. The Cusan universe is the concrete unfolding of God, and as such, ‘an infinite sphere, whose center is everywhere, whose circumference is nowhere’ (Cusa in Keller, 117). With nothing unperspectivally situated, no element or creature is closer to divinity than any other. Rather, God suffuses the cosmos at equal intensities everywhere, inhering as much in vegetality as in animality, as much in minerality as in intelligence. Thus we witness in Cusa what Keller calls ‘the breaking up of the face of God across an endless cosmic surface of faces’ (113). With faces pan-carnationally distributed, there is no static order of creation – no Great Chain of Being – which is to say no single path beyond the world to God.

Already, then, Keller's Cusa makes two radical departures from Neoplatonic negativity: first, it follows not one but an endless number of indeterminate paths, and second, these paths lead to a God within the world rather than a God outside it. Of course, God also exceeds the created order – as Keller points out, Cusa evades even the stingiest charges of pantheism (94) – but here divine transcendence is inseparable from cosmic enfolding and unfolding. In other words, it is a transcendence that secures relation, without capitulating to Thomist analogy and its tireless relinkings of the old Great Chain. It is a transcendence, moreover, that unsettles relation's tiresome verticality, fragmenting it out across all imaginable vectors. As Keller so deftly explicates, if God is in all things and all things are in God, then we can only conclude that ‘all are in all and each is in each’ (Cusa in Keller, 114). Or in Kellerian terms, incarnation is pan-carnation and pan-carnation is inter-carnation (118, 308). Here, then, Keller unveils the coincidentia of the apophatic and the relational, of the cloud and the crowd, of the beyond and the between.

Having sketched this logic so convincingly in Cusa, Keller tracks it backward and forward from the Ur-scene at Sinai through a crowd of medieval mystics through the puzzling revelations of quantum mechanics through Whitehead, Whitman, Butler, Glissant, Deleuze, global capital, and climate science – before heading back once more to the beginnings and ends of scripture. ‘The cloud surrounding whatever we try to say about “God” here enfolds the entire crowd of our relations’ (5), Keller writes, insisting throughout this book's multi-disciplinary adventure that the unknowability inherent to our human, animal, vegetal, and quantum interactions secures the possibility of relation to begin with – and of transformation to re-begin with.

In addition to the daring and, I would suggest, now-authoritative reading of Cusa, the Cloud’s most significant contributions include a stunning waltz with a cosmo-queer Whitman, some new life breathed into the stodgy Cappadocians, an ecological intermingling of Whitehead and Deleuze, and perhaps most impressively, a central chapter on quantum entanglement. Calling upon Bohm, Bohr, and Barad, Keller traces the development of Bell's Theorem – along with Einstein's strenuous resistances thereto and contemporary extensions thereof – finding in it a particulate confirmation of Jeanette Winterson's neo-Cusan intuition that ‘the separateness of our lives is a sham’ (Winterson in Keller, 127). Offering a light-handed and clear-headed exposition of entanglement's ‘spooky action at a distance’ (Einstein in Keller, 128), Keller holds this phenomenon in tension with quantum uncertainty (or indeterminacy, depending on whether one sides with Heisenberg or Bohr), finding in this duality an uncanny recapitulation of the relational on the one hand and the apophatic on the other.

Here, then, we witness the constitutive collision of physics with metaphysics, the quantum with the theological. Nevertheless, Keller is careful to assure us she is not seeking in this disciplinary entanglement some scientific confirmation of, say, the God-hypothesis. As she explains it, ‘a theology of apophatic entanglement would not be able to insert its God into this particular quantum opening even if it wanted to. What kind of congealed God-entity plugs gaps anyway? Only an idol steps in as the explanation of the inexplicable and the determiner of the indeterminate’ (145). Rather than chasing the endorsement of ‘science’, Keller reverses our critical gaze, uncovering in the history and philosophy of physics a surprisingly theological cover-up. Just as the orthodox philo-theological tradition has managed to plug its apophatic holes with ‘God’ as ‘substance’, she suggests, physics has tended to over-write even quantum indeterminacy with the dictum, ‘shut up and calculate’ (128). Certain segments of modern physics, just like certain segments of theology and philosophy, have tended to try not to know what they know, imposing upon themselves a ‘willful ignorance’ that might productively be countered by something like a ‘learned ignorance’ (21), an apophatic exposure of our most intimate relations.

It is Keller's hope, of course, that such apophatic exposure might compel us to imagine our relations otherwise. And here it seems important to note that entanglement for Keller is neither good nor bad, if one can even speak this way. Rather, entanglement is, and as such can be either respected or abused, mindfully engaged or mindlessly ignored. For example, one could see in the escalating, ecocidal racism of the ever-globalizing West a ‘stranglehold of capitalist entanglement’ (255) from which there can be no material or mystical escape. The ethical response to such deathly relationality is not, however, disengagement – after all, it is precisely disengagement that sustains the inane illusions of endless progress, individual ‘responsibility’, and trickle-down development. Rather, Keller explains, the antidote to capitalist entanglement is ‘planetary entanglement’ (255), specifically, a recognition of the economic devastation, toxic neighbourhoods, infectious diseases, uninhabitable homelands, and endless warfare that overdevelopment rains upon its constitutive ‘elsewheres’. Against capitalism's willed ignorance, then, Keller calls us to a learned ignorance, whose constant effort to know collides with unknowing precisely in the forms of its manifold entanglements. And from the luminous darkness of this cloud-crowd, perhaps we might engender a different sort of relation – a creatio ex profundis, ex multitudine, ex nube – right here in the mess of things, where ‘hope . . . remains clouded, not canceled, by tragic knowledge and manifold uncertainty’ (312).