The concept of change is central to what is itself a central part of the Christian faith: salvation. Acceptance of Christ’s atoning work transforms us, as it is often expressed, from ‘Old Being’ to ‘New Being’. We are in effect new creations, and our relationship with God is restored. We can think of this in global terms, as a transformation of the entire human race or human natures, or in individual, personal terms, as something that happens to a person in their lifetime – or indeed both of these. It would perhaps be possible to conceive of the first as something that obtains outside time. But the second is surely a change taking place in time. Moreover, talk of ‘New Being’ or ‘New Creation’ implies a change in the fabric of reality itself, something becoming present that was not there before.

And yet, at the beginning of the twentieth century there was a sustained challenge to our ordinary notion of change, and indeed of time itself, from two quite independent sources. The first, in 1905, was Einstein’s paper introducing the Special Theory of Relativity. The second, in 1908, was McTaggart’s proof of the unreality of time. Though they appeal to wholly different considerations (respectively, the relativity of simultaneity, and the logical contradiction inherent in the idea of time’s passage), they point to the same conclusion: reality does not contain an objective distinction between past, present and future. Both led to the development of a conception of reality known as the ‘block universe’, where all times are equally real, there is no time that is uniquely and objectively present, nothing comes into existence, and nothing recedes into the past. Can our ordinary conception of time be accommodated within this picture? McTaggart argued that genuine change must involve temporal passage: the poker was hot but now is cold. As there is no such thing as passage, there is no such thing as change. And, since time entails change, there is no time either. Einstein, in contrast, did not set out to establish the unreality of time, but the relativity of simultaneity nevertheless appears to rule out the notion of an objective present, for if two events are really present, must they not be absolutely simultaneous?

So, we face a difficulty. Salvation requires (it seems) a genuine change in what is real, which itself requires objective becoming. Yet, there are compelling considerations from both physics and philosophy which argue that there is no such thing as objective becoming. What is the way out of this conundrum? Abandon or fundamentally revise this most central of Christian doctrines? Reject the science and logic behind the arguments against becoming? Or treat science and religion as non-communicating forms of discourse? The last of these does not seem compatible with a realist approach to both science and religion – that is, one that takes them as attempts to say something true about reality itself. This apparent inability of the block universe to accommodate salvation is the problem Emily Qureshi-Hurst tackles in Salvation in the Block Universe. Simply defining the problem, as she does, in sharp, explicit, and lucid terms, is a significant contribution in itself. But she also has a wholly original, far-reaching, and exciting solution to the problem, drawing on both the theology of Paul Tillich and contemporary metaphysics of time.

The book is divided into two parts. In Part I, the motivation for the block universe view is set out, starting with considerations from metaphysics. McTaggart’s distinction between the A-series (temporal passage), B-series (directed temporal order), and C-series (undirected non-temporal order) is introduced, and his argument that there is a contradiction in the notion of the A-series expounded. Various alternatives to the block universe view are considered, including the growing block (real past and present, unreal future) and presentism (unreal past, real present, unreal future). The discussion then turns to science, and in particular the Special and General Theories of Relativity. It is argued that the relativity of simultaneity and time dilation effects are not compatible with an objective present, and the cosmic time introduced by the General Theory does not provide a viable means of saving objective passage. The final chapter of Part I critically examines what is often regarded as the most compelling consideration in favour of objective passage: experience. Time just seems to pass! Yet, if reality is comprised of a block universe, either the experience as-of passage is illusory (a view known as illusionism), or many metaphysicians are mistaken in thinking we do have an experience as-of passage. Of these, Qureshi-Hurst argues that illusionism is the best option. The block universe theorist now has to offer an error theory of that experience. The success of such a theory thus undermines the argument from experience to passage. Qureshi-Hurst’s presentation of the case for the block universe is remarkably comprehensive, accessible, and up to date. A reader with no previous acquaintance with the debates would be very efficiently brought up to speed by this discussion alone.

If one aspect of the debate about passage gets relatively short shrift in this otherwise balanced discussion, it is presentism. What recommends it is that it provides an intuitive way of preserving passage from McTaggart’s attack. The main challenge it faces is to give an account of the truth of statements about the past, given that there is no real past to provide any truth-makers. Qureshi-Hurst takes this to be a decisive objection, although (not surprisingly) presentists have developed some quite sophisticated responses. But it would be unfair to offer this as a criticism, for without some selectivity on the author’s part the discussion of time would threaten to engulf the whole book.

Part II turns to theology, and in particular the theology of Paul Tillich, as set out in his Systematic Theology. As the author points out, Tillich tends to be relatively neglected in contemporary theology, and one of the aims of Salvation in the Block Universe is to encourage people to engage once again with this important twentieth-century writer. The relevance of Tillich to this discussion is threefold. First, the problem which is the focus of this book is here framed in terms of the ‘method of correlation’: the identification of a problem thrown up by contemporary culture and of a theological response to that problem. Tillich himself, writing in the 1950s, identified existentialism, and its associated feeling of anxiety, alienation, and absurdity, as the contemporary cultural challenge. It might be said, although Qureshi-Hurst does not pursue this, that the illusionism concerning ordinary experience that she argues is a consequence of the block universe view might itself contribute to feelings of alienation: the landscape revealed by contemporary science (a central part of our culture) is a very strange and unsettling one. The second aspect of Tillich’s relevance is his account of salvation, which is framed in psychological terms. Fallenness is conceived in terms of those very feelings of anxiety, alienation, and meaninglessness associated with existentialism, and salvation is relief from those feelings as a result of a realignment with reality. And the third aspect is Tillich’s view of time. Qureshi-Hurst is careful not to attribute an explicit metaphysics of time to Tillich, but two features of his writings on the subject are noteworthy: one is that he talks of time in tensed terms – in terms, that is, of a past, present, and future. The other is that he is influenced by Kant’s notion that some categories we attribute to the world, such as space, time, and causality, are in fact projected by us so as to make sense of experience. Putting these two features together suggests an interesting possibility that becomes particularly salient when Qureshi-Hurst presents her own response to the problem.

That response is the subject of the final chapter, ‘Salvation and Transformation in the Block Universe’, and she names it ‘mind-dependent salvation’, a title and idea inspired by Adolf Grunbaum’s account of mind-dependent becoming. Grunbaum had argued that, although there is no objective becoming, there is a subjective or mind-dependent becoming, as a result of the mind’s changing temporal perspective on reality. We represent times as past, present and future because those times are inevitably experienced from our own perspective (cf ‘here’ and ‘there’, ‘I’ and ‘you’). But the facts which give rise to that perspective are entirely objective. The sense in which there is genuine change in the block universe is simply that different states of affairs obtain at different times. Apply this now to salvation, conceived in Tillichian terms. Objectively, it is true that at one stage the individual experiences anxiety and alienation and at a later time experiences a release from these feelings. But, from the individual’s perspective, this is experienced in tensed terns: the feelings of alienation become past, and release becomes present. For that individual, reality itself appears different: a new state of affairs is represented as coming into existence. The ordering of states is objective, but their being subject to passage is mind-dependent. All this is entirely consistent with the block universe view. But that view, it is conceded, does rule out the objective becoming of our saved state. We can express this in Kantian terms: becoming is something we (unwittingly, since it is by our very nature) impose on our experience so as to be able to interpret it.

This account of mind-dependent becoming and salvation is even compatible with a view some think is the inevitable consequence of the block universe: that we are four-dimensional ‘worms’ spread out in spacetime, and what we think of as the persistence of a single individual through time is in fact simply a sequence of numerically non-identical temporal parts. This in fact is part of the original challenge, for if this is the right account of persistence then it seems that the person who is fallen and the person who is saved, belonging as they do to different times, cannot be one and the same. But here again mind-dependent salvation comes to the rescue, for the individual experiences themselves as persisting as a single person through time and undergoing the salvific process.

The achievement of Salvation in the Block Universe is a very considerable one. It sets out a new and very serious challenge to Christian theology, and clearly displays the nature of the challenge by a detailed but accessible exposition of both temporal metaphysics and relativistic physics. But it also offers an exciting and original account of salvation which, while inspired by Tillich, is set in the context of a well-worked out scientific and psychological model of time, change, and freedom.

This review will conclude with a few questions, rather than criticisms, raised by the discussion.

One question is how much the initial problem is really one specifically of tense (the objectivity of the distinction between past present and future) or of existence. One way in which Qureshi-Hurst articulates the problem posed by the block universe is that, when an object changes from being in one state to being in another state there is no one consistent answer to the question ‘what state is the object really in?’, for both states are equally part of reality at all times. (This has become known as the ‘problem of temporary intrinsics’.) But this is true also of a version of a tensed view of time, that is one which allows objective passage, namely the growing block, where both past and present are real. So if this criterion is insisted on, it seems there are only two options; presentism, according to which only one of these states is presently real, or temporal part theory, in which the object that is in one state and the object that is in another state are different objects.

The second question is how much the central challenge is a peculiarly modern phenomenon. Granted, relativistic physics begins only with the twentieth century. But the conception of time to which it led has medieval antecedents in the conceptions of eternity found in Augustine and Aquinas. Book XI of the Confessions certainly identifies some conundrums to do with time’s passage and offers a view of Divine eternity which is tenseless. Augustine appears to be inviting us to contemplate a view of passage, and indeed change, as mind-dependent. What, then, sub specie aeternitatis, constitutes salvation?

A third question concerns direction. The only one of his three series McTaggart attributes reality to is the C-series: an ordered but undirected (and so non-temporal) series. Qureshi-Hurst takes mind-dependent salvation to be compatible with a view on which time and change constitute a C-series rather than a B-series. This more radical version of the block universe view has been championed in recent years by Huw Price. There may be an entropy gradient, he argues, but no direction from earlier to later times: direction is as perspectival as tense. At this point, the defender of the Christian doctrine of salvation, whether Tillichian or not, might be expected to dig their heels in. Even if experience is paramount, among the objective facts grounding our subjective experience of salvation, surely, must be the fact that we progress from a fallen state to a saved state. A mere ‘salvific gradient’ is not sufficient.

But this is just one illustration of the way in which this rich and provoking book opens up a new agenda (and, to be fair, Qureshi-Hurst mentions a causal grounding for the direction of salvation as one possible avenue for future exploration, along with other investigative lines, such as the theological implications of quantum mechanics). And the case it makes, through a striking example, for the viability and importance of genuine dialogue between science and religion is, to my mind, a virtually unassailable one.