Eternalism and the B Theory of Time: Is the Future Real?
Eternalism is the view that past, present and future events are all equally real, so that the whole of history forms one four-dimensional "block" in which tomorrow exists as surely as yesterday. It usually travels with the B theory of time and stands against presentism, the view that only the present exists. Frame-Indexed Classical Theism holds that the eternalist is right about the block as God holds it, and wrong only when calling our experience of passage an illusion.
Key takeaways
- Eternalism says every time is equally real. The past has not vanished and the future is not nothing; both belong to one block universe.
- Relativity describes spacetime's geometry; it does not prove the block. Putnam's argument from physics is contested, and the reality of the future rests on more than physics.
- Each rival saves one thing and loses another. Presentism keeps the moving now and loses the past; the growing block keeps the past and loses the future.
- Frame-Indexed Classical Theism (FICT) keeps both. Where B-theory eternalism denies real passage and presentism denies the past and future, it holds the block real as God sustains it and passage real as we live it.
What is eternalism, and why does it matter?
Eternalism is a claim about what exists. As Wikipedia's article on eternalism puts it, eternalism "is an ontological view according to which all existence in time is equally real." Some forms treat time much as we treat space, with future events "already there" in the same sense other places are already there, and with "no objective flow of time." On this picture, the year 1000 and the year 3000 are no less real than this morning. They are simply located elsewhere along the fourth dimension, much as Jerusalem and Rome are located elsewhere along the other three.
Eternalism is a claim about existence, not about causes. It does not say that the past fixes the future in advance, only that the future is there. Whether a real future leaves room for freedom is a separate question, and the answer below takes it up directly.
The vocabulary of the debate comes from J. M. E. McTaggart's 1908 paper "The Unreality of Time." McTaggart distinguished two ways of ordering events. The A-series orders them as past, present and future, and those positions shift: the cross was once future, then present, and is now past. The B-series orders them as earlier than, simultaneous with and later than, and those relations never change. The a theory of time holds that the A-series describes something real, that there is an objective present and time really passes. The b theory of time holds that the B-series is the whole truth, and it is the natural partner of eternalism.
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Eternalism has three main rivals. According to the Stanford Encyclopedia of Philosophy, "According to presentism, only present objects exist." The growing block theory holds that "only objects that are either past or present exist," so reality grows at the leading edge of the present. The moving spotlight theory is "an eternalist A-theory," a complete block with an objective present sweeping along it.
These are not idle puzzles for the Christian. The faith rests on events: a crucifixion under Pontius Pilate, an empty tomb, a promised return. If the past is nothing, what makes it true that Christ rose? If the future already exists, in what sense are we free? And how does God know the end from the beginning? The last question belongs to the doctrine that God is omniscient, and to the long dispute over whether God knows the future.
Volume Three of the series takes up each of these questions.
The case for eternalism at its strongest
The strongest case for eternalism comes from physics. Einstein's special relativity shows that simultaneity is relative: two observers moving relative to each other will disagree about which distant events are happening "now." In 1966 C. W. Rietdijk published "A Rigorous Proof of Determinism Derived from the Special Theory of Relativity," and in 1967 Hilary Putnam published "Time and Physical Geometry." Their argument is simple in outline. What is real for me now includes what is simultaneous with me. What is simultaneous with a moving observer beside me includes events in my future. If reality is the same for both of us, my future is already real. Putnam concluded, in the words Wikipedia reports, that "any future event X is already real."
The Stanford Encyclopedia agrees that relativity "creates serious difficulty for the A-theory in general and for presentism in particular." If no universal now exists in physics, a theory that makes the now the boundary of all reality looks stranded.
The second argument is McTaggart's. Time requires change, he reasoned, and only the A-series changes, so time needs the A-series. Yet every event must be future, present and past, and these properties exclude one another. "McTaggart also argues that the A series is inherently contradictory," as the Stanford entry summarises. Add tenses to avoid the clash ("it was future, is present, will be past") and you appear to need a second time in which the first one moves, and then a third. Many B-theorists accept his attack on the A-series and reject only his conclusion that time is unreal. The block, they say, is all the time there is.
The third argument presses on presentism. "Caesar crossed the Rubicon" is true. Yet if only the present exists, there is no Caesar, no Rubicon and no crossing to make it true. The eternalist has an easy answer: the crossing is real, at its own location in the block.
Eternalism also has a theological pull. Augustine taught that God is not in time and that time exists only within the created universe, a view the doctrine of creation from nothing makes natural. And Scripture presents God as the one who sees history whole:
"I make known the end from the beginning, from ancient times, what is still to come. I say: My purpose will stand, and I will do all that I please." (Isaiah 46:10, NIV)
The verse comes from God's challenge to the idols of Babylon, which cannot foretell or save. It is a claim about His knowledge and His purpose, not about physics. Many eternalists still find it at home in a block that God beholds entire.
Each of these arguments is weighed in the series, beginning with Volume One, which you can read free.
A theory vs B theory of time: the standard answers at their strongest
Four answers dominate the literature. Each has able defenders, and each sees something true.
B-theory eternalism
The B-theorist accepts the block and denies that any moment is objectively present. In the Stanford Encyclopedia's summary, "B-theorists think all change can be described in before-after terms." "Now" works like "here": it picks out where the speaker is, not a special place in reality.
The view's strengths are real. It fits the geometry of relativity without strain. It gives past and future truths something to be true of. Its strain is the one critics have long felt. If nothing objectively passes, then our experience of passage, of the present as alive and the future as not yet, is a feature of minds and not of the world. J. R. Lucas, quoted in the same Wikipedia article, put the complaint in one line: "The Block universe gives a deeply inadequate view of time."
Presentism
Presentism is the A-theorist's natural home. It honours what nearly everyone feels: the present is where we act, the past is gone and the future is not yet made. Among Christian philosophers, William Lane Craig is its most prominent defender, and he meets the relativity argument directly. Physics, he argues, is open to a neo-Lorentzian interpretation that "posits a 3+1 dimensional ontology featuring a privileged time and a privileged rest frame," and on his reading special relativity "does not support the tenseless theory of time but is fully compatible with the A-Theory." The two readings make the same predictions, so experiment cannot choose between them.
Presentism strains at two points. The past needs truthmakers that presentism has trouble supplying. And it needs a privileged present that physics cannot detect. Volume Six, Resolving Rest and Relativity, takes up what physics can and cannot say about an absolute frame.
The growing block
C. D. Broad and, later, Michael Tooley proposed a middle way. The past and present are real; the future is not. Reality grows as new moments come into being. The Internet Encyclopedia of Philosophy describes the view's future as "indeterminate or merely potential."
The growing block keeps the settled past that presentism loses and the open future that eternalism seems to close. It also matches ordinary experience closely: what has happened cannot be undone, and what has not happened is still to be decided. Its cost is the future itself. If tomorrow is nothing, there is nothing yet for God to know, and the view sits close to open theism. Relativity also offers it no universe-wide edge along which to grow, though that alone does not refute it.
The moving spotlight
Bradford Skow defends a bolder hybrid: the whole block exists, and a metaphysical spotlight of presentness moves along it. This keeps the completed block and an objective now together. The strain is McTaggart's. If presentness moves, it seems to move through a further time, and McTaggart's regress returns.
Each answer guards something true: the reality of the whole, the reality of the present, the settledness of the past, the openness of the future. And each assumes that "time" means one thing for every knower.
Volume One sets out the method behind the answer that follows, and it is free to download.
How Frame-Indexed Classical Theism answers the eternalism debate
Frame-Indexed Classical Theism (FICT) is a research program in analytic theology that dissolves classical theological dilemmas by diagnosing them as artifacts of a single error: one term carried across two frames as though it meant the same thing in each. On time, B-theory eternalism says the block is real and passage is not, while presentism says the present is real and the block is not. FICT keeps the block and the passage, because the two answers are about the one timeline taken in by two kinds of knower.
The question "Does time pass?" sounds as though it has one answer for every mind. It does not. God's nature and ours differ in kind, and a being's nature fixes how it takes in reality, as the series' opening chapters argue. God, who is eternal and simple, holds the whole of created history in one act of knowing and sustaining. From His frame, nothing about the timeline is still to come. The eternity of God is the subject of its own article; here it is enough that the block is what the created order is as God holds it.
"Before the mountains were born or you brought forth the whole world, from everlasting to everlasting you are God." (Psalm 90:2, NIV)
"For a thousand years in your sight are like a day that has just gone by, or like a watch in the night." (Psalm 90:4, NIV)
We are finite. We cannot take in the whole of history in one act, so we take it in one moment after another. For us the present is privileged, the past is fixed and the future is not yet reached. That succession is no illusion. It is the real way a finite creature exists, and Scripture addresses us inside it:
"Now listen, you who say, 'Today or tomorrow we will go to this or that city, spend a year there, carry on business and make money.' Why, you do not even know what will happen tomorrow. What is your life? You are a mist that appears for a little while and then vanishes. Instead, you ought to say, 'If it is the Lord's will, we will live and do this or that.'" (James 4:13-15, NIV)
James tells the merchants that tomorrow is not theirs to command. It is held by the Lord's will.
So the B theory is the true description of the created order as God holds it, and the A theory is the true description of that same order as we live it. The contradiction appears only when one description is stripped of its frame and used to deny the other. Book Three uses a homely image: one road is "uphill" to the climber and "downhill" to the one descending, and we do not call the road contradictory.
Two cautions apply. First, physics does not prove the block. Relativity describes the metric structure of spacetime; the reality of the future rests on God's sustaining of the whole, the ground of being for every moment. Second, this is not relativism. There is one timeline and one truth about it, taken in two ways, and the difference between the ways follows from the difference between Creator and creature. The statement of FICT sets out the position in one place.
The whole argument is the central chapter of Resolving Time and Eternity.
Five tested objections to this account of eternalism
We have run thousands of simulated attacks against Frame-Indexed Classical Theism, drawn from academic and peer-reviewed sources. Five of them bear directly on eternalism, pressed from the positions of B-theory eternalists, presentists and growing block theorists.
Doesn't relativity prove eternalism by itself?
Here's one of those attacks and how the Many Beings framework would address it.
Rietdijk and Putnam supply this attack. FICT says the reality of the future rests on God's sustaining. But why bring God in? Relativity of simultaneity, together with the plain principle that what is real for one observer is real for any observer beside him, already entails that future events are real. Eternalism follows from physics alone, and the theological ground is idle.
Physics leaves the question open, and the record shows it. The argument needs the premise that "real for me" is fixed by a relativistic simultaneity slice. Philosophers of physics such as Howard Stein and Steven Savitt reply that "the present is a local concept that cannot be extended to global hyperplanes," and Wikipedia's own summary calls the Rietdijk-Putnam reading "not universally accepted." Craig's neo-Lorentzian interpretation predicts every measurement Einstein's does while keeping a privileged present. When two readings of the same equations agree on every experiment and disagree about whether the future exists, the equations have not settled that question.
FICT does not adopt Craig's privileged physical frame. It cites his reading only to show that relativity underdetermines the metaphysics. Relativity describes the four-dimensional metric structure of the created order, and FICT accepts that description without reservation. The further claim that the unexperienced future is no less real than the past is not something a clock can register. It is grounded in God's eternal sustaining of the whole. Putnam and Craig stand in a genuine standoff, and FICT's claim is scoped to say exactly what physics can and cannot carry.
Isn't the A-series simply contradictory?
Here's one of those attacks and how the Many Beings framework would address it.
McTaggart's charge, which B-theorists such as Mellor accept and presentists such as Craig reject, runs this way when an analytic theologian presses it. FICT says the a theory of time is the true description of time as we live it. But McTaggart showed that the A-series is internally contradictory: every event must be past, present and future, which is impossible. A contradiction is a contradiction in every frame, so assigning the A theory to the creature's frame does not dissolve it. It imports it.
McTaggart's contradiction depends on treating tense as a one-place property that an event carries in itself, the same way in every frame at once. Only then must the crucifixion be past, present and future together. That is a picture of the event surveyed from nowhere in particular, all at once. Within our finite frame, no event is ever past, present and future together. It is future, then present, then past, each tense tied to the knower and the moment. Indexed that way, "the crucifixion is future" (said by David) and "the crucifixion is past" (said by us) no more conflict than a town that lies "north" of one traveller and "south" of another.
What FICT assigns to the creature, then, is a tensed way of apprehending a real timeline, not a set of tense-properties that events carry in isolation. The law of non-contradiction holds in full; its condition, "in the same sense," is never met. McTaggart's paradox turns out to be an argument against unindexed time, not against time.
Isn't frame-relative presentness just the B theory in disguise?
Here's one of those attacks and how the Many Beings framework would address it.
Craig himself presses this one. In The Tensed Theory of Time, he argues that the A-theorist's defining commitment is presentness as a real, non-relational property. If presentness is merely relative to an observer, that is exactly the B-theorist's analysis of "now." So a view that makes presentness relative to a frame has already conceded the B theory and abandoned the A theory it claims to keep.
Craig's dilemma assumes a single frame. It demands that presentness be either absolute for everyone or merely relative for everyone. FICT says neither. Within the creature's frame, presentness is genuinely and objectively privileged: it is the real frontier where our potential becomes actual and where we act. That is not a token-reflexive reduction; for us it is the deepest fact about our existence in time. Within God's frame, there is no moving present at all, because every moment is immediately before Him.
So the A-theorist is right about the creature and the B-theorist is right about the Creator's grasp of the created order. Presentness is described as frame-relative only when one stands outside both frames and asks how the two descriptions relate. Craig's charge removes that index, and with it the distinction FICT draws.
If God holds the whole block, isn't passage an illusion?
Here's one of those attacks and how the Many Beings framework would address it.
The attack draws on Kit Fine's fragmentalism and D. H. Mellor's tenseless theory. If God's complete grasp of the whole block is the privileged, maximal description of reality, then the maximal description contains no now. Passage becomes a perspective the absolute description lacks. That is either Fine's picture of reality as a set of fragments with theology added, or Mellor's view that tense lives only in minds. Either way, eternalism has made our experience of passage unreal at the top level.
The defense is that God's frame is not one fragment among equals, and it is not a rival perspective competing with ours. It is the ground of ours. God does not merely observe the timeline from outside; He sustains the creature as it moves through it. Passage is therefore real because it is sustained: a real but bounded way of being in time that God upholds, not an appearance produced by a mind looking at a static picture. The objection predicates "real" in one sense across both frames and then infers that what is absent from God's way of knowing must be absent from reality.
God's providence works the same way. God's eternal decree does not make our choices unreal, because He sustains them as ours. In the same way, the block does not make passage unreal, because He sustains our passage as ours.
If the future already exists, how can it be open?
Here's one of those attacks and how the Many Beings framework would address it.
This attack sets eternalism against C. D. Broad's growing block. The whole reason Broad and Tooley made the future nothing was to keep it open. Eternalism says future events exist simpliciter. FICT also says the future is an open, branching path for the creature. Those are two answers to one question, "Does the future exist?", and no frame-indexing can make one manifold both complete and still branching.
The answer is that the future is real and settled for the Creator, and genuinely open for the creature. Volume One argues at length for genuine, indeterministic finite freedom, and Scripture addresses us as choosers before real alternatives:
"This day I call the heavens and the earth as witnesses against you that I have set before you life and death, blessings and curses. Now choose life, so that you and your children may live." (Deuteronomy 30:19, NIV)
Moses puts a real choice before Israel and commands it. Reducing that openness to mere ignorance would be the mistake, because it would collapse real possibility into necessity.
The classical distinction between the necessity of the consequence and the necessity of the consequent does the work. Given that God eternally knows a choice, the choice is certain. It is not thereby necessary in itself, within the chooser's own frame, and the agent keeps the power to choose otherwise. Had he chosen otherwise, God's eternal knowledge would always have been of that. The full case against fatalism is in the article on theological fatalism, and the freedom it protects is libertarian free will.
The series carries the same testing into immutability, infinity and physics.
Frequently asked questions about eternalism
What is eternalism in simple terms?
Eternalism is the view that the past, the present and the future are all equally real. History is like a landscape laid out in time: yesterday has not disappeared and tomorrow is not nothing. Each moment simply sits at its own location in what philosophers call the block universe, and "now" marks where we happen to be within it.
What is the difference between eternalism and presentism?
Presentism holds that only the present exists; the past is gone and the future is not yet. Eternalism holds that all times exist equally. Presentism keeps the felt reality of the now but struggles to say what makes truths about the past true. Eternalism grounds those truths easily but must explain why the present seems special.
Is eternalism the same as the B theory of time?
Not quite. The B theory of time says that events are ordered only by earlier and later, with no objective present. Eternalism is a claim about existence: all times are real. Most B-theorists are eternalists, but the moving spotlight theory combines eternalism with an objective, moving present, so the two can come apart.
Does eternalism mean free will is an illusion?
Not necessarily. The future's being real does not by itself make any choice compelled. Presentism and the growing block deny that the future exists partly to keep it open. Frame-Indexed Classical Theism holds that the future is settled as God knows it and genuinely open as we face it, and that God's certain knowledge of a free choice does not make the choice necessary in itself. The choice is known because it is freely made.
Is eternalism compatible with Christianity?
Many Christian thinkers have held something close to it, since Augustine taught that time is created along with the world. The real question is what makes the future real. Physics alone does not settle it. On the classical view, God sustains every moment of history in one eternal act, and Augustine's question about what God was doing before creation shows how early the tradition saw time as a creature.
Where this leaves the block
The eternalist looks at history and sees a finished whole. The A-theorist looks at the same history and sees a river still running. Both are looking at one creation, and each is seeing something that is really there. The whole is real because God holds it, and the river is real because He carries us along it, and neither picture needs to be torn down to save the other.
Volume One sets out the method from first premises, and it is yours free.
