1.2.1 Scripture

Scriptural depictions of God’s relationship to time are complex and cannot easily be sorted into a single clear model. Generally, however, God is depicted as being intimately involved in the unfolding of creation, interacting within history in a way that seems to show that he is a temporal being. Exactly what this means will be explored later, but a working definition of a temporal being is a being who has some or all of the following: temporal properties, temporal extension, temporal location, and an experience of temporal passage. In other words: a being who exists in, and experiences, time. Psalm 102:23–28, for example, says of God:

Long ago you laid the foundation of the earth, and the heavens are the work of your hands. They will perish, but you endure; they will all wear out like a garment. You change them like clothing, and they pass away; but you are the same, and your years have no end.

This passage describes God as creating the cosmos ‘long ago’, with each creative act involving change enacted by a changeless God. The temporality of God is difficult to unpack here – an immutable God is contrasted with a changing cosmos, but God does seem to be actively involved in the temporal cosmos as it changes (i.e. the phrase ‘you change them like clothing’). To gain a fuller picture, one must look to other scriptural passages.

The successive nature of creative acts is never clearer than in the Genesis narratives. In Genesis 1 God creates the universe in stages, with creation coming into being over the course of six creatively active epochs. First, God ‘separated the light from the darkness […] and there was evening and there was morning, the first day’ (Gen 1:4–5). In this passage God creates worldly time, and this time continues to structure the creation narratives and the divine action within them. Similarly, in Genesis 3, God converses with and walks alongside Adam and Eve, interacting with them in a temporal mode. Throughout the Hebrew Bible, God is shown to be active in the unfolding of human history. He commands (Exod 3–4), he punishes (Gen 7), he rewards (Job 42:10–17), and he enters into a covenant with his people (Gen 6:18; Isa 54:9; Num 25:10–13). In other words, he responds to events as they happen, engaging in a dynamic relationship with the world. Similarly, the New Testament tells of God taking on flesh, becoming human, and seeming to live as a temporal being (John 1:14). If God is triune, as Christianity claims, then according to the doctrine of homoousios the temporal status of one trinitarian person must be shared by the others. Each divine person must have the same divine nature. All of this seems to indicate that the God of the theologians is temporal.

Despite this, according to the aforementioned Psalm, God’s temporality is unlike that of humans; he is expected to outlive creation and remain unchanged throughout, possessing ‘years’ everlasting. Similarly, Ps 90:2 claims that God exists ‘from everlasting to everlasting’. The majority of Christian tradition has understood God as eternal, meaning God exists without beginning or end, and is not within the temporal dimension that frames creaturely existence. In order to see why, this article will now turn to some key voices in the Christian tradition. Whilst it is impossible to cover all the voices that comprise this corpus, it will survey some of the most notable figures. The contemporary literature will be discussed in section 3 and section 4.

1.2.2 Tradition

The Platonic idea of divine immutability had a significant impact on the development of theological reflection on God and time. Divine immutability, namely the idea that God cannot change, combines elements of Plato’s ontology of the Forms – which are perfect, immaterial, and unchanging – with perfect being theology. Plato argued in Republic (Republic 381b–c) that a perfect being cannot change because they are unable to improve, being already perfect, and they cannot deteriorate as this would mean they cease to be perfect. Following the Aristotelian commitment to unity of time and change, a being who cannot change was believed to be outside of time by necessity. Divine immutability reverberated throughout Christian tradition, its legacy lasting for centuries. It is arguably a leading reason why divine atemporality played such a significant role in Christianity’s intellectual history.

The first theological voice to consider is St Augustine of Hippo (354–430), who reflected on time in the autobiographical Confessions. Augustine famously wrote that time is elusive and hard to define: ‘what, then, is time? If no one asks me, I know: if I wish to explain it to one that asks, I know not’ (Confessions XI; Augustine of Hippo 1999: Book XI). He makes a distinction, one that has been reached for many times since, between divine eternity and created temporality. The former is the (a)temporal mode that characterizes God’s eternal life, whilst the latter is imperfect and limited by the experiential context of creatureliness. Augustine seems to have believed that the creaturely experiential context leads us to encounter time as though it is dynamic and tensed, in that it flows and is fragmented into past, present, and future. For the perfect and immutable God, however, there is no distinction between tenses or times; instead, all moments are held together in eternity. Divine time is eternal (tenseless, unified) and stands over and above, and is ontologically superior to, created time. Whilst our senses ‘flutter between the motions of things past and things still to come’, God dwells in ‘the glory of everfixed eternity’ – these states are radically different in kind (Confessions XI; Augustine of Hippo 1999: Book XI).

Another notable writer whose contribution to this debate has been significant and enduring is Anicius Manlius Severinus Boethius (c. 475–c. 526). Boethius defined eternity in the following way:

Eternity, then, is the complete possession all at once of illimitable life. This becomes clearer by comparison with temporal things. For whatever lives in time proceeds as something present from the past into the future, and there is nothing placed in time that can embrace the whole extent of its life equally [...] it does not yet grasp tomorrow but yesterday it has already lost; and even in the life of today you live no more fully than in a mobile, transitory moment. [...] Therefore, whatever includes and possesses the whole fullness of illimitable life at once and is such that nothing future is absent from it and nothing past has flowed away, this is rightly judged to be eternal, and of this it is necessary both that being in full possession of itself it be always present to itself and that it have the infinity of mobile time present [to it]. (Title V.6; Boethius 1969, emphasis added)

From this definition, Eleonore Stump draws out four components: (1) anything eternal has a life, (2) the life of an eternal being cannot be limited by beginning or end, (3) eternity involves infinite duration, and (4) an eternal being possesses all its life at once, meaning it cannot be temporal (Stump 2003: 133–134).

Anselm of Canterbury (1033–1109) also reflected on the relation between divine eternity and creaturely temporality. In conjunction with much of the theological corpus, Anselm was committed to the doctrine of divine simplicity. According to this doctrine, God is a perfect metaphysical unity, his essence is equal to his attributes, and he is not comprised of parts (temporal or otherwise). Such a view has led many, Anselm included, to reject the idea that God’s experience could be split up into temporal parts, namely ‘what is’, ‘what has been’, and ‘what will be’. Rather, an omniscient, perfectly simple God would experience all of creation at once in a timeless unity. From divine simplicity follows atemporality. In his Proslogion, Anselm presented his famous definition of God as a being than which no greater can be conceived (which has since been developed into the ontological argument for God’s existence). If God is a perfect being, then he cannot change, because any change would necessarily be a form of degeneration. Thus, on the basis of these doctrines, Anselm concluded that God must be timelessly eternal.

St Thomas Aquinas (1225–1274), the medieval thinker whose writings have left the most significant impact on the development of Christian theology, can be read as having two distinct points of focus when it comes to the topic of God and time. First is his discussion of divine eternity, and second is his treatment of the relation between God and temporal creation. He argued that God has no beginning or end, and God does not experience succession, passage, or change. Along with most other medieval philosophers, Aquinas endorses both Boethius’ definition of eternity and the classical theological doctrines of divine simplicity and immutability, leading him to the same conclusions as Anselm. Echoing Boethius, Aquinas holds that all times are atemporally known by God at once. Aquinas illustrates this through the metaphor of standing at the summit of a mountain with an entire landscape before you:

God, however, is wholly outside the order of time, stationed as it were at the summit of eternity, which is wholly simultaneous, and to Him the whole course of time is subjected in one simple intuition. For this reason, He sees in one glance everything that is affected in the evolution of time, and each thing as it is in itself, and it is not future to Him in relation to His view as it is in the order of its causes alone (although He also sees the very order of the causes). (Commentary on Interpretation I.14.20)

One ought not to take the metaphor too literally, however. God does not perceive events in time like some eternal and external onlooker. For Aquinas, God atemporally knows all the facts about history by knowing their cause (i.e. himself). Since God predetermined all things, he knows all things before they exist. So God does not need to be within time to have knowledge of what happens within the temporal, created, sphere.

As this snapshot shows, for a significant portion of Christian history God was understood as existing outside time. Divine eternity was thus interpreted as atemporal – existing always but not in a way structured by passage, duration, or temporal location. The alternative view understands divine eternity to mean everlasting existence – God exists for all time, experiences the passage of time as it unfolds, and has a mental life that is temporally structured. It is this view that has risen to prominence in recent years, led by scholars like William Lane Craig, Richard Swinburne, Nicholas Wolterstorff, and Ryan Mullins. This view will be discussed in section 3.

2.2.1 Special relativity

The Special Theory of Relativity, introduced by Albert Einstein in 1905, catalysed a revolution in our understanding of space and time (Einstein 1905; 2010, originally published 1920). Newtonian Mechanics, the scientific paradigm that previously dominated this intellectual space, held time to be absolute and wholly independent of objects or observers. In Philosophiae Naturalis Principia Mathematica, Newton argued that ‘absolute, true, and mathematical time, of itself, and from its own nature, flows equably without relation to anything external, and by another name is called duration’ (Newton 1934: 6–12, Scholium to Definition viii). Thus Newton was committed to the objective passage of time and the existence of an absolute present moment that structures that passage.

Special Relativity profoundly violated these postulates, sending shockwaves reverberating throughout the scientific community. Rather than space and time being absolute, Special Relativity (following Minkowski’s geometric formulation) indicated that each are distinct dimensions of four-dimensional Minkowski space-time, and one’s measurement of length and duration is, to some extent, observer dependent. In a paper published in 1908, Minkowski made his now famous proclamation that, as a result of Special Relativity, ‘space by itself, and time by itself, are doomed to fade away into mere shadows, and only a kind of union between the two will preserve an independent reality’ (Minkowski 1908). What this means in practice is that observers travelling at different speeds will disagree on the duration and distance between the same two events. This has been empirically confirmed many times over since Einstein introduced it in 1905 (Brown 2005: 82–87). Importantly, within Special Relativity there are no privileged observers, meaning no single observational perspective can take precedence over any other. What this leads to is the so-called relativity of simultaneity, namely the claim that objective simultaneity relations cannot be substantiated within the special theory. Because there will be variation in distance and duration between different frames of reference, and there is no observer-independent way to choose between these, the notion of an absolute simultaneity relation becomes untenable. That appears to lead to the conclusion that the special theory is incompatible with the existence of a universal present moment.

There is some dispute over both the correct interpretation of Special Relativity and its domain of application, however, and several interpretations of the content of the theory are available. The most widely accepted, at least within physics, is generally referred to as the space-time interpretation (or the Einstein-Minkowski interpretation). The space-time interpretation holds that Special Relativity ought to be taken at face value, and that we ought not to postulate the existence of further structures or processes than those contained within the bare bones of the theory. As such, the space-time interpretation is founded upon operationalist principles, a point of contention amongst critics.

The Operationalist defines scientific concepts in terms of the operations used to measure them, i.e. time is equivalent to whatever is measured by clocks (Einstein 2010: 22). In the context of Special Relativity, the Operationalist would state that if we are unable to measure absolute simultaneity then no such relation exists. As such, the space-time interpretation is committed to the following three claims:

1. Space and time are distinct dimensions of the more fundamental entity space-time.
2. One’s measurement of duration and length is determined by one’s frame of reference.
3. The reason absolute simultaneity relations cannot be reconciled with Special Relativity is because they do not exist.

This must then be applied to the categories introduced in section 2. For an A-theory to be the correct description of time, there must be an objective, changing, universal now at which point potential future events come into being when they become present. Such a present moment must be sharp, clearly defined, and unambiguously separate the (unreal) future from the past. Although the Moving Spotlight view is committed to the existence of the future, it is the A-theory with the most structural problems and thus has the fewest proponents. A profound problem for both Presentism and the Growing Block is raised by Special Relativity’s denial of absolute simultaneity relations (and thus, an absolute present moment). The relativity of simultaneity is problematic for the existence of a universal now because, according to Special Relativity, some events (specifically, spacelike separated events) are future in one reference frame and present in another. This generates the contradictory conclusion that future events both exist and do not exist.

The first proponent of such an argument was the philosopher Hilary Putnam (1967: 242). Putnam pointed out that Presentism denies that the future exists, but Special Relativity shows that certain events in my future (i.e. events the Presentist says are unreal) are in your present (i.e. events the Presentists says are real). Thus, Presentism plus Special Relativity leads to the contradictory conclusion that some events both exist and do not exist. As contradictions cannot be part of reality, the space-time interpretation is incompatible with any A-theory of time that is committed to the unreality of the future. The Moving Spotlight is also ruled out due to its commitment to a universal present moment, i.e. an objective ‘now’, which is incompatible with the relativity of simultaneity. The space-time interpretation instead supports a four-dimensional space-time ontology which unites the three dimensions of space with the one dimension of time, namely a B-theory or C-theory.

A prominent alternative (though still a minority view in physics and metaphysics) is the neo-Lorentzian interpretation devised and defended by William Lane Craig. Craig is a presentist who has, for partly philosophical but primarily theological reasons, spent much of his career defending the A-theory of time against Special Relativity, the philosophy of temporal language, and McTaggart’s argument against the A-theory. His argument runs as follows:

1. God exists.
2. The A-theory of time is correct.
3. If an A-theory of time is correct, there are tensed facts and temporal becoming.
4. If God exists and there are tensed facts and temporal becoming, then God knows tensed facts and is the cause of things’ coming to be.
5. If God knows tensed facts and is the cause of things’ coming to be, then God is temporal.
6. There are tensed facts and temporal becoming (2, 3).
7. God exists and there are temporal facts and temporal becoming (1, 6).
8. God knows tensed facts and is the cause of things’ coming to be (4, 7).
9. God is temporal.
10. If God is temporal, then a privileged reference frame exists.
11. If a privileged reference frame exists, then a Lorentzian interpretation of SR is correct.
12. A privileged frame exists (9, 10).
13. A Lorentzian interpretation of SR is correct (11, 12) (Craig 2001: 165).

One can identify three primary claims that underly this argument. First, Craig is committed to the existence of some form of background structure which functions as a preferred frame of reference. Against this preferred frame of reference, the objective passage of time can be measured, and absolute simultaneity relations can be recovered within physics. Craig suggests a range of possibilities (2001: 165). Second, he invokes the distinction between metaphysical, divine time on the one hand, and relative, physical time on the other, reminiscent of a similar distinction made by Newton. In contrast to the space-time interpretation, Craig interprets time dilation and length contraction as consequences of relative, measured time and space and not absolute metaphysical time.

Rejecting Operationalism, Craig argues that our inability to empirically measure absolute time is no more than a consequence of our methodological limitations. An omniscient God would know which events are happening now according to the standard set by absolute metaphysical time, even if we creatures are unable to access this information. Craig therefore takes Special Relativity as describing physical processes only, leaving the metaphysical time (grounded in divine time) untouched. For this reason, he is still able to endorse Presentism. The third and final claim is theism. Craig argues that, for theological reasons which shall be discussed in section 4, God must be temporal, and a temporal God only makes sense in an A-theoretic universe. His position is often referred to as a 3+1 space-time ontology, as it is committed to a clear distinction between three-dimensional space and one-dimensional time. Which of these is preferable will depend on one’s prior commitments, one’s theological position, and the extent to which one believes theology ought to weigh in on matters of scientific interpretation. For a comprehensive assessment of the scientific viability of neo-Lorentzian relativity, see a review article by Yuri Balashov and Michel Janssen (2003). For another argument that presentism is compatible with Special Relativity, see Zimmerman 2011. A third option, the so-called inhomogeneous flowing time interpretation of Special Relativity, is offered by Robert John Russell (2012; 2022).

2.2.2 General relativity

Special Relativity is not the final word on matters spatial and temporal, however. In 1915 Einstein published his General Theory of Relativity. The general theory is less straightforward in its support of one temporal ontology over another. In contrast to the Newtonian understanding of gravity as a force acting between massive bodies, General Relativity reconceptualized gravity as the warping of four-dimensional space-time by massive bodies. A common metaphor for understanding what this means is that of a sheet held taut at each corner with a bowling ball at the centre. The mass of the bowling ball will stretch the sheet around the curvature of its surface, and the heavier the ball the greater this warping will be. If a smaller ball, say, a tennis ball, were rolled past it, its trajectory would be affected by the curvature of the sheet. The tennis ball may even begin spinning around the bowling ball in a facsimile of orbital motion. The effect on the two-dimensional surface of the sheet is not unlike the way celestial bodies like stars and planets warp the four-dimensional space-time in which they dwell.

The warping of space-time affects more than the motion of celestial bodies, it also affects observer’s measurements of temporal duration. This is because light always takes the shortest path between two points. In flat space-time, this is a straight line. If space-time is curved, however, then light will be travelling a greater distance along the curvature of space-time than it will where space-time is flatter. A ‘straight line’ in curved space-time is known as a geodesic. In General Relativity, light follows space-time geodesics, and the greater the curvature of space-time the greater the distance light must travel. Regardless of one’s observational perspective, one must always measure the speed of light as c, whether one is in a region where space-time is curved or flatter. Because speed = distance ÷ time, the fixity of the speed of light means that observers will disagree on distance or duration if they are in different locations relative to a given massive body. In other words, an astronaut could be on a massive planet for an hour in their time, but on returning to their spaceship much further out in the gravitational field they could find that their colleagues who remained on the ship had measured ten years between the astronaut leaving and returning.

Despite these divergences in duration between observational perspectives, some A-theorists have argued that their case is strengthened when moving on from Special Relativity to General Relativity. Both Richard Swinburne and William Lane Craig have argued that certain solutions of Einstein’s field equations, each of which corresponds to a possible world, can substantiate what they have called ‘cosmic time’. These solutions are known as the Friedman-Lemaître-Robertson-Walker (henceforth FLRW) cosmological solutions, and each of them maps the structure of a possible universe. FLRW universes possess the following properties: (1) homogeneity (the universe is the same at every point), (2) isotropy (there is no preferred direction in the universe), (3) expansion (the overall size of the universe evolves dynamically). Because of these symmetries, one can foliate space-time in such a way that globally extended instants, i.e. universal nows, emerge. Cosmic time acts as a universal measure of how much time has elapsed since the beginning of the universe, and thus, according to its proponents, can once again recover the notion of an absolute present moment within physics. This is because cosmic time gives an observer-independent and objective way of measuring the passage of time (Swinburne 2008: 224).

It is possible to critique this approach from a number of different angles, each of which is explored in greater detail by Read and Qureshi-Hurst (2021). One possible route is to argue that focusing on cosmological solutions of General Relativity changes the theory under consideration, abandoning the appropriate object of focus. Another option is to argue that FLRW solutions depict universes with perfect homogeneity, isotropy, and expansion, meaning that they are not descriptions of the actual world which does not exhibit these perfect symmetries. We should, according to this critique, only care about whether the A-theory is compatible with our actual world, not some abstract idealization. A third response is to argue that using cosmic simultaneity as a vehicle for grounding an objective past/present/future distinction is inappropriately motivated. A primary motivation for endorsing an A-theory is to recover our experience of temporal passage. Yet our experience is shaped by local time, not cosmic time. In fact, the latter is radically disconnected from our experience, so it cannot establish the kind of temporal passage the A-theorist requires. Finally, one might follow Gödel in presenting a modal argument to the effect that whether a universe manifests primitive tensed properties cannot be a contingent affair. Since (for technical reasons) it would have to be a contingent affair in General Relativity, there can exist no such objective tensed properties. Despite these criticisms, the A-theory invariably fares better in General Relativity than in Special Relativity. Whether it does enough to save the A-theory remains an open question.

2.2.3 Quantum mechanics

The two most successful physical theories are, at present, incompatible. General Relativity, a theory concerning gravity, describes the large-scale behaviour of cosmic objects and their interaction with curved space-time. Quantum mechanics, on the other hand, is concerned with the smallest scale of physical reality: subatomic particles. Whilst General Relativity describes space-time as continuous, namely infinitely divisible, quantum mechanics introduces granularity into myriad properties at the subatomic level, such as energy and length. These properties can only have certain values, functions of Plank’s constant, meaning that there is a minimum value below which they cannot go. This may turn out to be the case for space-time (and thus for the temporal dimension) if a Quantum Theory of Gravity is ever developed. At present, physicists do not agree about whether space and time are continuous or particulate.

Absolute simultaneity plays an important role in quantum mechanics despite it being incompatible with Special Relativity (and, perhaps, General Relativity as well). There are many interpretations of non-relativistic quantum mechanics, but in each an absolute space-time structure is taken for granted and Newtonian-style absolute time is used to mark the evolution of a quantum system. For example, interactions between entangled quantum particles great distances apart are faster than the speed of light, seeming to require instantaneous (thus absolutely simultaneous) spooky-action-at-a-distance of the kind forbidden by relativity.

All this goes to show that whilst physics can help illuminate the path toward answers about the nature of temporal reality, it does not hold all the answers. Whilst physicists’ empirical findings cannot be ignored in both the practices of temporal metaphysics and God and time discourse, nor can they be the sole participant in the discussion. Now that both objects of study, namely ‘God’ and ‘time’, have been set out, we are able to turn to their conjunction.

5.2.1 Salvation

The final areas of Christian thought that are relevant to time are the interrelated doctrines of salvation and eschatology. Christian theological accounts tend to envisage salvation as involving a process of chronological transformation. For example, Augustine’s idea of Christ as a physician who both causes and superintends the healing process in a patient. However, a salvation-transformation, at least the kind of personal transformation that an individual might undergo in their lifetime, looks rather different depending on whether you endorse an A-theory like Presentism or a B/C-theory like eternalism. Salvation requires change, and this change is generally thought to be a total, ontological transformation, of the kind that brings the individual into a new state of being and a far deeper relationship with the divine.

Ben Page examines such ontological transformation, particularly as discussed in St Paul’s second letter to the Corinthians: ‘if anyone is in Christ, there is a new creation: everything old has passed away; see, everything has become new’ (2 Cor 5:17). Page notes that a key feature of an ontological transformation is that it affects the physical, mental, and spiritual dimensions of an individual’s personhood (Page 2018: 526). Such a transformation may take place via ‘mixing’, in which an individual’s ontology becomes combined with either created grace or the Holy Spirit, or ‘radical replacement’, in which the individual is ontologically transformed through the replacement of some of their temporal parts from sinful parts to saved parts.

An A-theory of time can easily accommodate this latter kind of transformation. If time passes, and humans are comprised of temporal parts (as in a perdurantist theory of identity), then an individual’s temporal parts are continuously replaced at every new moment of time. An A-theory allows God to create the individual anew with saved parts, replacing the old fallen parts, and thus the individual has undergone a complete ontological transformation with respect to those parts. The sinful parts are truly gone. Andrew Hollingsworth makes a similar point, arguing that the only temporal ontology compatible with the true elimination of sin from both humanity and creation is Presentism, because, on any theory committed to the concrete existence of past moments, ‘past evils and sins would “still” exist (for God at least) and would not be truly eliminated’ (Hollingsworth 2024: 2).

As such, the Eternalist Block Universe view has a harder time accommodating a salvation-transformation. According to M.O. Fiocco, ‘an entity changes if and only if it in itself is one way at one moment and an incompatible way at a distinct moment’ (Fiocco 2014: 89, original emphasis). Similarly, D. H. Mellor writes: ‘changes are things having, at different times, incompatible properties, i.e. properties that no one thing could have at the same time’ (Mellor 2012: 169). In the static temporal ontology of the Block Universe this is evidently troubling, as all objects (including human persons) always exist, extended throughout space-time like a four-dimensional worm. Thus, each iteration of that object at each moment of its life always exists. In what sense, then, can we say an individual can undergo the type of transformation required for salvation? A salvation-transformation requires the kind of change in which the same entity possesses different properties at objectively different times. This type of change requires a kind of newness that seems incompatible with the metaphysics of the block universe. Entities change when they possess new properties that they did not possess before. I have undergone a salvation-transformation because I was fallen at some past time, and I am now saved in the present. This does not seem compatible with the Block Universe, or indeed any temporal ontology committed to the existence of the past. A solution to this problem has been offered by Emily Qureshi-Hurst which involves reconceptualizing the salvation transformation as a subjective rather than an objective, robust, ontological change (2022a; 2022b).

5.2.2 Eschatology

According to Christian eschatology, at the end times, (maybe a select few, maybe all) persons are raised from the dead and redeemed, reaching the eschatological goal of creation by being transformed into a ‘new creation’ characterized by eternal life and unity with God. This resurrection is believed to echo Christ’s resurrection insofar as it involves the physical body and not just an immaterial soul. Your body will ‘be raised imperishable, and […] will be changed’ (1 Cor 15:52). The same is believed to be the case for the rest of creation. Rom 8:18–30, for example, speaks of the groaning of creation and the promise of eschatological redemption for the entire physical universe. Thus eschatology traditionally requires (1) that physical creation persist in such a way that it can be transformed into a new creation, and (2) that the physical bodies of human beings can be raised to spend eternity with God.

The problem is, if Presentism is true, as many theists claim, then the physical body vanishes into the non-existent past after death and decay has set in. Even more troubling is that General Relativity predicts that the entire universe will end in one of two options: freeze or fry. Freeze refers to the heat death of the universe and predicts that over many billions of years the universe will reach maximum entropy whose temperature tends toward absolute zero, leaving a freezing and definitely uninhabitable soup of black holes and radiation. The latter, fry, is essentially the reverse of the Big Bang, namely a cosmic contraction in which galaxies rush toward each other leading to the eventual implosion of the entire universe into an extremely hot, infinitely dense and definitely uninhabitable singularity. Robert John Russell puts the problem this poses for Christian eschatology as follows:

For those who defend the bodily resurrection […] the challenge is obvious and severe: if the predictions of contemporary scientific cosmology come to pass (‘freeze’ or ‘fry’) then it would seem that the universe will never be transformed into a new creation, that there will never be a general resurrection, and this, in turn, means that Christ has not been raised from the dead, and our hope for resurrection and eternal life is in vain. (Russell 2002b: 267)

Fortunately for the theist, several solutions to this problem have been sketched out. These typically lean upon the resurrection of Jesus as the sign of what a new creation might be like and how a physical body might be resurrected, despite the possibility of a freeze or fry ending to the universe (Polkinghorne 2002; Ward 2002; Russell 2002a; 2002b; Wilkinson 2010). Each of these is discussed in detail by Qureshi-Hurst 2022b.