05 / 06
bird bird

God, Time, and Relativity

William Lane Craig at University of St. Andrews, Scotland

Time : 01:09:55

"God, Time, & Relativity: Exploring the Mutual Implications of Relativity Theory and Conceptions of Divine Eternity" at the PhysPhil Conference at the University of St. Andrews, Scotland.

Dr. Craig: "I presented a paper in which I argue that the Einstein's special theory of relativity did not, in fact, disprove Newton's concept of absolute time, which was rooted in Newton's theism, and that if we agree with Newton that God is in time, then we should interpret special relativity in a quite different way than Einstein did."

Includes open discussion at the end of Dr. Craig's presentation (43:48).


INTRODUCTION: He holds two PhD’s: one in philosophy and one in theology. His research interests are quite broad but for today we are going to focus on his research interests in the philosophy of time and theology – what is exactly God’s relationship to time? Over the years he published several volumes related to these issues. He has two different books, one on the tensed theory of time [1] and another on the tenseless theory of time [2] as well as two different volumes on God, time, and eternity [3] and a lay version called Time and Eternity [4] as well as a book on time and the metaphysics of relativity [5]. Craig holds a position that is not exactly traditional – he argues that God is temporal and not timeless yet he is not straight-up a temporalist. He holds that God is timeless sans creation and yet temporal with creation. Where relativity comes into play is that Craig holds to a tensed theory of time and it seems that relativity might cause a problem with this. Or relativity theory might entail that somehow God could be timeless if God does in fact exist. So these are some of the issues that Craig will address.

DR. CRAIG: Thank you very much. Well I, too, am very glad to be a participant in this conference and have enjoyed it so far. If Chris Hooley’s paper represented the best of all possible worlds because he had neither a presentation on PowerPoint nor a paper to be read then my paper must represent the worst of all possible worlds because I have got both.

“God,” declares the prophet Isaiah, “is the high and lofty One who inhabits eternity.” [6] But, being a prophet and not a philosophical theologian, Isaiah did not pause to reflect upon the nature of divine eternity. Minimally, to be eternal is to exist without beginning and end. To say that God is eternal means minimally that He never came into being and will never go out of being. To exist eternally is to exist permanently; for an entity is permanent if and only if it exists and has no first or last finite period of existence and there are no moments before or after it exists. There are, however, at least two ways in which something could exist eternally. One way would be to exist omni-temporally, throughout infinite time. In this case, God would have an immemorial and everlasting temporal duration. The other way in which a being could exist eternally would be by existing timelessly. In this case, God would completely transcend time, having neither temporal location nor temporal extension. He would simply exist in an undifferentiated timeless state. The question confronting the natural theologian in understanding God’s eternity concerns God’s relationship to time. Does God exist temporally or atemporally? God exists temporally if and only if He exists in time. That is to say, if and only if His duration has phases which are related to each other as earlier and later. In that case, as a personal being, God has experientially a past, a present, and a future. No matter what moment in time we pick, given God’s permanence, the assertion, “God exists now,” were we to make it, would be literally true. By contrast, God exists atemporally if and only if He is not temporal. This definition makes it evident that temporality and timelessness are contradictories. An entity must exist one way or the other and cannot exist both ways at once. If, then, God exists atemporally He has no past, present, and future. At any moment in time it would be true to assert “God exists” in the tenseless sense of exists, as when one says “the natural numbers exists” but not true to assert “God exists now.” [7]

Philosophical theologians have been sharply divided on the question of God’s relationship to time. One of the most important arguments motivating a doctrine of divine timelessness is based upon Albert Einstein’s Special Theory of Relativity, hereafter STR. In this paper I want to focus our attention on this particular argument.

According to Einstein’s special theory, there is no unique, universal time and so no unique, worldwide “now.” Each inertial frame has its own time and its own present moment, and there is no overarching, absolute time in which all these diverse times are integrated into one. So if God is in time, then, the obvious question raised by STR is: Whose time is He in?

The defender of divine timelessness maintains that there is no acceptable answer to this question. We cannot plausibly pick out some inertial frame and identify its time as God’s time because God is not a physical object in uniform motion, and so the choice of any such frame would be wholly arbitrary. Moreover, it is difficult to see how God, confined to the time of one inertial frame, could be causally sustaining events which are real relative to other inertial frames but are future or past relative to God’s frame. Similarly, God’s knowledge of what is happening now would be restricted to the temporal perspective of His frame, leaving Him ignorant of what is going on in other frames. In any case, were God to be associated with a particular inertial frame, then surely, as God’s time, the time of that frame would be privileged. It would be the equivalent of the privileged ether frame of classical physics. So long as we maintain, with Einstein, that no frame is privileged, then we cannot plausibility identify the time of any inertial frame as God’s time.

Neither can we say that God exists in the “now” associated with the time of every inertial frame, for this would obliterate the unity of God’s consciousness. In order to preserve God’s personal consciousness it must not be fragmented and scattered among the inertial frames in the universe. But, if God’s time cannot be identified with the time of a single frame or of a plurality of frames, then God must not be in time at all, that is to say, He exists timelessly.

We can summarize this reasoning as follows:

1. STR is correct in its characterization of time.

2. If STR is correct in its characterization of time, then if God is temporal, He exists in either the time associated with a single inertial frame or the times associated with a plurality of inertial frames.

3. Therefore, if God is temporal, He exists in either the time associated with a single inertial frame or the times associated with a plurality of inertial frames.

4. God does not exist in either the time associated with a single inertial frame or the times associated with a plurality of inertial frames.

5. Therefore, God is not temporal.

How shall we assess this argument? Well, let’s look at premise (2) first. Premise (2) is at best misleading in that it fails to take into account the fact that STR is a restricted theory of relativity and therefore is correct only within prescribed limits. It is a theory which deals with uniform motion only. The analysis of non-uniform motion, such as acceleration and rotation, is provided by the General Theory of Relativity, hereafter GTR. STR cannot therefore be expected to give us the final word about the nature of time and space; indeed, within the context of GTR a new and important conception of time emerges. For GTR serves to introduce into Relativity Theory a cosmic perspective, enabling us to draft cosmological models of the universe governed by the gravitational field equations of GTR. [8] Within the context of such cosmological models, the issue of time resurfaces dramatically. All contemporary cosmological models derive from Russian mathematician Alexander Friedman’s 1922 model of an expanding, material universe characterized by ideal homogeneity and isotropy. Although GTR does not itself mandate any formula for how to slice spacetime into a temporally ordered foliation, nevertheless certain models of spacetime, like the Friedman model, have a dynamical, evolving spatial geometry whose natural symmetries guide the construction of a cosmic time; in order to ensure a smooth development of this geometry, it will be necessary to construct a time parameter based on a preferred slicing of spacetime. Now as a parameter independent of spatial coordinates, cosmic time measures the duration of the universe as a whole in an observer-independent way; that is to say, the lapse of cosmic time is the same for all observers. Nevertheless, cosmic time is related to the local times of a special group of observes called “fundamental observers.” These are hypothetical observers who are at rest with respect to the expansion of space itself. Cosmic time relates to these observers in that their local times all coincide with cosmic time in their vicinity. Because of their mutual recession, the class of fundamental observers does not serve to define a global inertial frame, technically speaking, even though all of them are at rest. But since each fundamental observer is at rest with respect to space, the events which he calculates to be simultaneous will coincide locally with the events which are simultaneous in cosmic time. What this implies is that, contrary to premise (2), it does not follow from the correctness of STR that if God is in time then He is in the time of one or more inertial frames. For if God exists in cosmic time there is no universal inertial frame with which He can be associated.

But let that pass. Although it may come as something of a shock to many, it seems to me that the most dubious premise in the forgoing argument is premise (1). In order to understand why I say this it will be helpful to take a backward glance at Isaac Newton’s classical doctrine of absolute time and space which was superseded by STR. The locus classicus of Newton’s exposition of his concepts of time and space is the scholium to his definitions in the Principia Mathematica. In order to overcome what he called common prejudices concerning such quantities as time, space, place, and motion, Newton draws a dichotomy with respect to these quantities between absolute and relative, true and apparent, mathematical and common. With respect to time he asserts, and I quote,

Absolute, true, and mathematical time, or itself, and from its own nature, flows equably without relation to anything external, and by another name is called duration: relative, apparent, and common time, is some sensible and external (whether accurate or unequable) measure of duration by the means of motion, which is commonly used instead of true time; such as an hour, as day, a month, a year. [9]

The most evident feature of this distinction is the independence of absolute time from the relative measures thereof. Absolute time, or simple duration, exists regardless of the sensible and external measurements which we try, more or less successfully, to make of it. [10] Newtonian time is thus first of all absolute in the sense that time itself is distinct from our measures of time.

But Newton also conceived of time as absolute in yet a more profound sense. Namely, he held that time exists independently of any physical objects whatsoever. Usually this is interpreted to mean that time would exist even if nothing else existed; that we can conceive of a logically possible world which is completely empty except for the container of absolute space and the flow of absolute time. But here we must be very careful. Modern secular scholars tend frequently to forget how ardent a theist Newton was, and how central this theism played in his metaphysical outlook. In fact, Newton makes quite clear in the General Scholium to The Principia, which he added in 1713, that absolute time and space are constituted by the divine attributes of eternity and omnipresence. He writes,

[God] is eternal and infinite . . .; that is, his duration reaches from eternity to eternity; his presence from infinity to infinity. . . . He is not eternity and infinity, but eternal and infinite; he is not duration or space, but he endures and is present. He endures forever, and is everywhere present; and, by existing always and everywhere, he constitutes duration and space. Since every particle of space is always, and every indivisible moment of duration is everywhere, certainty the Maker and Lord of all things cannot be never and nowhere[11]

Because God is eternal, there exists an everlasting duration, and because he is omnipresent, there exists an infinite space. Absolute time and space are therefore relational in that they are contingent upon the existence of God.

In Newton’s view, God’s “now” is thus the present moment of absolute time. Since God is not “a dwarf-god” located at a particular place in space, [12] but is omnipresent, there is a worldwide moment which is absolutely present. Newton’s temporal theism thus provides the foundation for absolute simultaneity. The absolute present and absolute simultaneity are features first and foremost of God’s time, absolute time, and derivatively of measured or relative time.

Thus, the classical, Newtonian concept of time is firmly rooted in a theistic worldview. What Newton did not realize, nor could he have suspected, is that physical time is not only relative, but also relativistic, that the approximation of physical time to absolute time depends on, not merely the regularity of one’s clock, but also upon its motion. Unless a clock was at absolute rest, it would not accurately register the passage of absolute time. Moving clocks run slowly. This truth, unknown to Newton, was finally grasped by physicists only with the advent of Relativity Theory. Where Newton fell short, then, was not in his analysis of absolute or metaphysical time – he had theological grounds for positing such a time – but in his incomplete understanding of relative or physical time. He assumed too readily that an ideal clock would give an accurate measure of time independently of its motion. If confronted with relativistic evidence, Newton would no doubt have welcomed this correction and seen therein no threat at all to his doctrine of absolute time. In short, relativity corrects Newton’s concept of physical time, not his concept of absolute time. [13]

What Einstein did, in effect, was simply to remove God from the picture and to substitute in His place a finite observer. According to historian of science Gerald Holton,

Thus the RT [Relativity Theory] merely shifted the focus of space-time from the sensorium of Newton’s God to the sensorium of Einstein’s abstract Gedanken experimenter – as it were, the final secularization of physics. [14]

By rejecting Newton’s absolute time and space, and along with them the ether, Relativity Theory left behind only their empirical measures. Since these are relativized to inertial frames, one ends up with the relativity of simultaneity and of length.

What justification did Einstein have for so radical a move? How did he know that absolute time and space do not exist? The answer, in a word, is verificationism. Historians of science have demonstrated convincingly that at the philosophical roots of Einstein’s theory lies a verificationist epistemology, mediated to the young Einstein through the influence of Ernst Mach, which comes to expression in Einstein’s analysis of the concepts of time and space. [15]

In 1905, when Einstein published his paper on the electrodynamics of moving bodies, and for several years thereafter, he was a self-confessed epistemological pupil of Mach, and the epistemological analysis of space and time given in the opening sections of that paper clearly displays this influence. Mach’s positivism manifests itself most clearly in Einstein’s a priori rejection of absolute time and space and reliance of operational definitions of crucial concepts. Absolute time or a privileged frame is presumed not to exist because “to the concept of absolute rest there correspond no properties of the phenomena.” [16] It is taken for granted that, “all our judgments in which time plays a role” must have a “physical meaning.” [17] When it comes to judgments concerning the simultaneity of distant events, the concern is to find a “practical arrangement” to compare clock times. [18] In order to “define” a common time for spatially separated clocks, we assume that the time light takes to travel from A to B is equal to the time is takes to travel from B to A – a definition which presupposes that absolute space does not exist. Thus, time is reduced to physical time (clock readings) and space to physical space (readings of measuring rods) and both of these are relativized to local frames. Simultaneity is defined in terms of clock synchronization via light signals. All of this is done by mere stipulation. Through Einstein’s operational definitions of time and space, Mach’s positivism triumphs in the Special Theory of Relativity. Reality is reduced to what our measurements read; Newton’s metaphysical time and space, which transcend operational definitions, are implied to be mere figments of our imagination.

In Einstein’s other early papers on relativity, his verificationist theory of meaning comes even more explicitly to the fore. Concepts which cannot be given empirical content, and assertions which cannot be empirically verified in principle, are discarded as meaningless. In his article in the Jahrbuch der Radioaktivität und Elektronik of 1907, after giving his operational definitions for time and simultaneity, he asserts that to refer to the time of an event without reference to its inertial frame, has no sense (Sinn). [19] In his piece in the Physikalische Zeitschrift of 1909, he asserts that statements about the time of an event have no meaning (Bedeutung) unless one refers to clocks at rest in the relevant inertial system. [20] In his summary paper, Die Relativitäts-Theorie, published in 1911, Einstein expresses himself at greater length concerning the meaning of statements about time and space. [21] He says “in order to arrive at time specifications of a very precise sense” we use a prescription that relates to clocks which are relative to a certain coordinate system k. We have not gained simply a time, but a time relative to a coordinate system. “It is not said that time has an absolute . . . meaning. That is an arbitrary element which was contained in our kinematics.” [22] Einstein then proceeds to the second arbitrary element in kinematics: the absolute length of a body. “We now ask: how long is this rod? This question can only have the meaning: what experiments must we carry out in order to discern how long the rod is?” [23] Einstein then proceeds to describe the length measurement of a moving rod by means of synchronized clocks. By abandoning the presuppositions of absolute time and space and substituting in their stead operational definitions, Einstein reduces time and space to our measurements of them. He concludes, “Since we have in a precise way physically defined coordinates in time, every relation between spatial and temporal entities will have a very precise physical content.” [24] Statements about spatial or temporal relations which are metaphysical in character, that is, are independent of clocks, rods, and reference frames, are nonsense.

It is frequently asserted that as Einstein labored on the General Theory, he came to see the bankruptcy of Mach’s positivism. But this claim needs to be carefully qualified. What Einstein’s work on GTR in fact revealed to him was the inadequacy of Mach’s phenomenalism. Scientific theorizing is not the mere linking of observation statements, but involves a creative exercise of the mind, which is free to postulate theoretical entities not directly given in observation. Nevertheless, even after GTR he continued to regard such theoretical terms as meaningless unless they could somehow be linked to observation statements. In 1920, for example, he writes,

We thus require a definition of simultaneity such that this definition supplies us with the means by which, in the present case, he [the hypothetical observer] can decide by experiment whether both lightning strokes occurred simultaneously. As long as this requirement is not satisfied, I allow myself to be deceived as a physicist (and of course the same applies if I am not a physicist) when I imagine that I am able to attach a meaning to the statement of simultaneity. [25]

For physicist and non-physicist alike the statement that two events occur simultaneously is meaningless unless an operational definition can be given for that concept. Thus, he continued to cling to his rejection of metaphysical space and time. He says,

The only justification for our concepts and system of concepts is that they serve to represent the complex of our experiences; beyond this they have no legitimacy. I am convinced that the philosophers have had a harmful effect upon the progress of scientific thinking in removing certain fundamental concepts from the domain of empiricism, where they are under our control, to the intangible heights of the a priori. For even if it should appear that the universe of ideas cannot be deduced from experience by logical means, but is, in a sense, a creation of the human mind, without which no science is possible, nevertheless this universe of ideas is just as little independent of the nature of our experiences as clothes are of the form of the human body. This is particularly true of our concepts of time and space, which physicists have been obliged by the facts to bring down from the Olympus of the a priori in order to adjust them and put them in a serviceable condition. [26]

Einstein’s theory, far from disproving the existence of absolute space, actually presupposes its non-existence. All of this is done by mere stipulation. Reality is reduced to what our measurements read; Newton’s metaphysical time and space, which transcend operational definitions, are implied to be mere figments of our imagination. [27]

How, then, shall we asses the claim that STR has eliminated absolute time and space? Well, the first thing that needs to be said is that the verificationism which characterized Einstein’s original formulation of STR belongs essentially to the philosophical foundations of the theory. The whole theory rests upon Einstein’s redefinition of simultaneity in terms of clock synchronization by light signals. But that redefinition assumes necessarily that the time which light takes to travel between two relatively stationary observers A and B is the same from A to B as from B to A in a round-trip journey. That assumption presupposes that A and B are not both in absolute motion, though relatively stationary with respect to each other, or in other words that neither absolute space nor a privileged reference frame exists. The only justification for that assumption is that it is empirically impossible to distinguish uniform motion from rest relative to such a frame, and if absolute space and absolute motion or rest are undetectable empirically, therefore they do not exist (and may even be said to be meaningless).

But if verificationism belongs essentially to the foundations of STR, the next thing to be said is that verificationism is proved to be completely untenable and is now obsolete. The untenability of verificationism is so universally acknowledged that it will not be necessary to rehearse the objections against it here. [28] Verificationism provides no justification for thinking that Newton erred, for example, in holding that God exists in a time which exists independently of our physical measures of it and which may or may not be accurately registered by them. It matters not a wit whether we finite creatures know what time it is in God’s absolute time; God knows, and that is enough.

Now, I am not here endorsing Newton’s view on divine eternity; but I am saying that the natural theologian who, like Newton, believes God to be temporal need not be phased by STR, because STR’s claim that absolute time does not exist is founded essentially upon a defunct and untenable epistemology.

If we do suppose that God is in time, then how should we understand STR? Henri Poincaré, the great French mathematician and precursor of STR, helped to point the way. In a fascinating passage in his essay “The Measure of Time,” Poincaré briefly entertains the hypothesis of “an infinite intelligence” and considers the implications of such a hypothesis. Poincaré is reflecting upon the problem of how we can apply one and the same measure of time to spatially distant events. What does it mean, for example, to say that two thoughts in two people’s minds occur simultaneously? Or what does it mean to say that a supernova occurred before Columbus saw the New World? Like a good verificationist, Poincaré says, “All these affirmations have by themselves no meaning.” [29]Then he remarks, [30]

We should first ask ourselves how one could have had the idea of putting into the same frame so many worlds impenetrable to one another. We should like to represent to ourselves the external universe, and only by so doing could we feel that we understood it. We know that we could never attain this representation; our weakness is too great. But at least we desire the ability to conceive an infinite intelligence for which this representation could be possible, a sort of great consciousness which should see all, and which should classify all in its time, as we classify, in our time, the little we see.

This hypothesis is indeed crude and incomplete, because this supreme intelligence would be only a demigod; infinite in one sense, it would be limited in another, since it would have only an imperfect recollection of the past; it could have no other, since otherwise all recollections would be equally present to it and for it there would be no time. And yet when we speak of time, for all which happens outside of us, do we not unconsciously adopt this hypothesis; do we not put ourselves in the place of this imperfect God; and do not even the atheists put themselves in the place where God would be if he existed?

What I have just said shows us, perhaps, why we have tried to put all physical phenomena into the same frame. But that cannot pass for a definition of simultaneity, since this hypothetical intelligence, even if it existed, would be for us impenetrable. It is therefore necessary to seek something else. [31]

Poincaré here suggests that, in considering the notion of simultaneity, we instinctively put ourselves in the place of God and classify events as past, present, or future according to His time. Poincaré does not deny that from God’s perspective there would exist relations of absolute simultaneity. But he rejects the hypothesis as yielding a definition of simultaneity because we could not know such relations; such knowledge would remain the exclusive possession of God Himself.

Clearly, Poincaré’s misgivings are relevant to a definition of simultaneity only if one is presupposing some sort of verificationist theory of meaning, as he undoubtedly was. The fact remains that God knows the absolute simultaneity of events even if we grope in total darkness. Nor need we be concerned with Poincaré’s worry that such an infinite intelligence would be a mere demigod, since there is no reason to think that a temporal being cannot have a perfect recollection of the past. There is no conceptual difficulty in the idea of a being who knows all past tense truths. His knowledge would be constantly changing, as more and more events become past. But at each successive moment he could know every past tense truth that there is at that moment. Hence, it does not follow that if God is temporal, He cannot have perfect recollection of the past. Poincaré’s hypothesis suggests, therefore, that if God is temporal, His present is constitutive of relations of absolute simultaneity. Compare H. A. Lorentz’s illustration of a World Spirit in his letter to Einstein in January of 1915. In words regular to the General Scholium and Opticks of Newton, Lorentz broached considerations whereby he said, “I cross the borderland of physics.” He wrote,

A ‘World Spirit’ who, not being bound to a specific place, permeated the entire system under consideration or, ‘in whom’ this system existed and who could ‘feel’ immediately all events would naturally distinguish at once one of the systems U, U’, etc. above the others. [32]

Such a being, says Lorentz, could “directly verify simultaneity.” On this view, the philosopher J. N. Findlay was wrong when he said, “. . . the influence which harmonizes and connects all the world-lines is not God, not any featureless, inert, medium, but that living, active interchange called . . . Light, offspring of Heaven firstborn.” [33] On the contrary, the use of light signals to establish clock synchrony would be a convention which finite and ignorant creatures have been obliged to adopt. But the living and active God who knows all would not be so dependent. In God’s temporal experience there would be a moment which would be present in absolute time, whether or not it were registered by any clock time. [34] He would know without any dependence on clock synchronization procedures or any physical operations at all which events were simultaneously present in absolute time. He would know this simply in virtue of his knowing at every such moment the unique class of present tensed truths at that moment without any need of physical observation of the universe.

So what would become of STR if God is in time? From what has been said, God’s existence in time would imply that H. A. Lorentz, rather than Einstein, had the correct physical interpretation of the mathematical core of Relativity Theory. That is to say, Einstein’s clock synchronization procedure would be valid only in the preferred (or absolute) reference frame, and measuring rods would contract and clocks slow down in the customary special relativistic way when in motion relative to the preferred frame. Such an interpretation would be implied by divine temporality, for God in the “now” of absolute time would know which events in the universe are now being created by Him and are therefore absolutely simultaneous with each other and with His “now.” This startling conclusion shows that Newton’s theistic hypothesis is not some idle speculation but has some important implications for our understanding of how the world is and for the assessment of rival scientific theories.

Lorentzian relativity is admitted on all sides to be at least empirically equivalent to Einsteinian relativity, and there are even indications on the cutting edge of physics today that a Lorentzian view may be preferable in light of recent discoveries. In fact, due to developments in quantum physics there has been what one participant in the debate has called a “sea change” in the attitude of the physics community toward Lorentzian relativity. [35]

Again, none of this proves that Newton was right in thinking that God is in time, but it does undercut the claim that STR has proven Newton to be wrong. The defender of divine temporality can plausibly reject the first premise of the argument for divine timelessness based on the Special Theory of Relativity.

In conclusion, Relativity Theory does not provide good grounds for thinking that God is timeless. The Einsteinian interpretation of STR is based essentially upon an untenable and obsolete verificationist epistemology and so cannot force abandonment of the classical concept of absolute time which is constituted by God’s durations. Moreover, GTR in its cosmological application furnishes us with a cosmic time parameter which may be plausibly interpreted as the appropriate measure of God’s time since the moment of creation.

QUESTION: I was wondering, however, on your insistence on the role of verification – that is essential to the picture that you want to bring out. We no longer believe in verificationism, so we know that what is empirically meaningless is not necessarily meaningless, period. But it is still the case that an omniscient, good God in the natural world, if absolute space and time are empirically meaningless, then, assuming Special Relativity and a model of the natural world, then absolute space and time don’t play any role in the nature world. [36] So one can still take Special Relativity at face value as showing that within the natural world there is no absolute space and time which implies saying that it is perfectly meaningful to talk about absolute space and time and leave them in the theological realm.

DR. CRAIG: I think it is clearly meaningful to talk about notions of absolute simultaneity and absolute length, even if these are not empirically verifiable, but I would disagree when you said that therefore they play no role in physical theory because, if they do exist, then there is structure to spacetime or to space that doesn’t exist according to the Einsteinian interpretation of STR. The Lorentzian interpretation, the physical interpretation of the Lorentz transformation equations which are at the heart of the theory, is a different interpretation than both the Einsteinian interpretation in the 1905 paper as well as Minkowski’s 1908 reformulation of it in terms of a four-dimensional geometry. These differences between the physical interpretations of the theory were glossed over by the positivists because so long as they were empirically equivalent, they could be regarded as the same theory. But with the collapse of verificationism and positivism, what we have here are different ontological structures. And so it is not a matter of indifference; it does make an ontological difference whether or not we’re talking about Lorentzian relativity versus Einsteinian or Minkowskian relativity. Now, whether or not this is detectable, as I say, that is right now a very controverted question on the cutting edge of physics, to which earlier speakers have already alluded (in the violation of the Bell inequalities by Aspect’s experiments and what implications this may have for establishing absolute simultaneity). But we can leave that all aside; I think the more fundamental pints is, once you get rid of verificationism, these are not the same theories, these are different ontologies.

QUESTION: In that same vein, I want to talk a little bit about your interpretation of (inaudible). I wish that Brian Higgs were here to give this talk because I think that he would be speaking of Einstein’s difference between theories of explanation versus theories of construction, and I that is what he is doing in these statements. He is not giving an ontological interpretation in terms of verification of what is going on in space and time in STR; he is talking about the way these things proceed in his theorizing in “The Electrodynamics of Moving Bodies” by saying, look, Lorentz and Poincaré are not getting anywhere by thinking about what the smallest bits of the theory are and trying to construct something out of that. Instead, I am going to approach the whole problem by thinking about “What have we actually measured? What principles do we already have?” We have the speed of light (we know that is a limitation), we also know that frames are invariant, and the laws of physics are very invariant. And so starting from those two things we can derive all this other stuff. So, when he is explaining STR he is not saying something ontological about space and time based on the fact that he started in his paper from principles of what we’ve actually measured, he is not saying because we have these things empirically that is it, there is no meaning to anything else. It was just the way he approached the problem.

DR. CRAIG: I think you are quite right in distinguishing between theories of explanation and theories of principle, and that this is a theory of principle, as you say. The Special Theory, as Einstein developed it, is explanatorily vacuous. The three-dimensional objects that undergo these deformations as they are in uniform motion relative to each other are real physical deformations. These rods actually contract up, the clocks actually slow down, this is not mere appearance. And there is no explanation for this at all, as you say, in the original paper; they are simply deductions from the two postulates. But what is critical to see, and here is where I think you are overlooking something, is that those two postulates are not themselves empirically established. [37]The postulate of the sameness of all physical laws in every reference frame is based upon the assumption that absolute space does not exist. Otherwise, the two postulates of the theories are in contradiction to each other, the two postulates cannot both be true, unless you presuppose that absolute space does not exist. So, that is why I said the theory doesn’t really disprove absolute space and time, it actually presupposes it. And those twin postulates cannot be established empirically; they are, as you say, just postulates, just principles that one accepts based upon the assumption that absolute space does not exist. And that assumption is rooted in this epistemology of verificationism that says if you cannot detect it, then it isn’t real. And Lorentz in his correspondence with Einstein came back to this over and over again. He would say just because you can’t detect something empirically doesn’t mean it is not real. And so the great predecessors of STR, like Poincaré and Lorentz, were never convinced that Einstein’s interpretation was right because they did not accept the postulates.

QUESTION: Thanks very much. This is just a question of clarification of terminology, really. So, as I’m sure your familiar, the word absolute, when its used with respect to space and time can be used to mean a number of different things, and one of the things that ‘the absolute’ often gets confused with is this idea that there is a preferred frame of reference. So, as you said a minute ago, the real difference between these two interpretations is an issue of what we take to have to be a part of the structural foundations of the world, a structural foundation of spacetime, it is a structural issue. Maybe the idea that there is a preferred frame of reference is the idea that spacetime has more structure or less symmetry than under any other interpretation. So, how much does any of this really hinge upon whether or not space or time or spacetime exist as entities and how much of an issue of what kind of a structure do those things have? So, I guess the questions is, could I be a relationalist, not believe in substantival spacetime, and still take your side on this?

DR. CRAIG: Absolutely, yes, I think so. And, in my book on this I list and explain six different meanings of the word absolute that are in the literature: absolute vs. relational; absolute vs. frame dependent; the word is used in about six different ways, I’ve used two of them in the paper today. And, any of these theories can be given a spacetime formulation in terms of this four-dimensional geometry. But if you hold to a tensed view of time, according to which temporal becoming is real, then I think you should reject the Minkowskian four-dimensionalist spacetime realist view according to which the future is just as real as the present is as real as the past. And if you do that then, if Minkowski is out, then what you’re left with is either Lorentz or the original Einsteinian interpretation in the 1905 paper. And, as I said, that 1905 paper is explanatorily vacuous; it posits these mysterious deformations of three-dimensional objects without any sort of explanation at all for why it occurs, and the Minkowskian also sees this as a deficit of the relativity interpretation and instead wants to postulate a four-dimensional geometry. But if you hold to the objectivity of temporal becoming and tensed time then you are going to throw out that spacetime realism and, I think, have a tensed theory that is more plausibly Lorentzian than Einsteinian.

FOLLOWUP: Sure, and if I could, just to clarify, then it is an issue of what kind of structural properties the material world has. I mean, you could even say that time, spacetime, whatever, does not actually exist, but your perspective would then translate into a claim about what kind of structural properties the material world has?

DR. CRAIG: My only hesitation is when you say “material world,” because, you see, as a theist like Newton, I want to root this absolute simultaneity and absolute now or the present in God’s time, which isn’t material. I would see the material realm as being derivative from God’s metaphysical time. [38] In fact, when you think about it, it seems to me that the universe is a clock, the universe is God’s clock. It measures the duration of God’s absolute time from the moment of creation forward in cosmic time. So, I’d hesitate with respect to saying, “of the material world,” but yes to what you said about postulating this structure of a sort of hyper-surface of simultaneity on which present events exist and with respect to which temporal becoming is an objective feature of reality.

QUESTION: So, if I understood correctly, all these problems started with the problem of a frame, of a special kind of frame. But we actually do have an absolute frame, which is the speed of light. So given that the Bible identifies God with light, it appears to me that God does not live in time, but first time with reality and then acts also as a reference for time.

DR. CRAIG: Now, the speed of light, being the same in all reference frames, does not serve to define a unique frame in the Special Theory. But, with respect to God, I haven’t given any arguments here for thinking that God is temporal, but I do that in my other work. I would argue that, given a tensed view of time, that God’s omniscience (knowing the truth of all tensed truths) and his causal connection to a world of temporal becoming necessitates that God is in time. So I give independent arguments for thinking that if God exists, He is temporal, in view of his omniscience and causal connection to the world. And critical here will be your theory of time. I am arguing for a tensed theory of time.

QUESTION: You stated, if I understood correctly, that there is this absolute reference frame and if when I’m moving at a velocity with respect to this absolute reference frame that the meter stick changes size and the clock slows down, wouldn’t that give an empirical way of finding out the reference frame because you would just look for the one with the longest meter stick and the shortest second?

DR. CRAIG: No, because for observers in motion relative to the absolute frame there is not any way to empirically detect that you’re not the one at rest, and that the other frame is the one that’s moving. So, unless these recent experiments with respect to Bell’s theorem and the violation of Bell inequalities suggest that these two photons have relations of absolute simultaneity between them, either when the point of collapse occurs or they are correlated in some way, that would be the best way of establishing relations of absolute simultaneity. So people like J. S. Bell, for example, advocated going back to Lorentz in order to best explain the violation of Bell inequalities. Otherwise, what you get are causal influences going backwards in time relative to some frame, but if you have relations of absolute simultaneity then you won’t have that, so that would be, I think, the best bet empirically of establishing this preferred frame.

QUESTION: Thanks for your talk. There is something I came across recently in a book by Lee Smolin called, The Trouble with Physics. [inaudible]. He points out something which many physics graduates [inaudible], he said that there is at least one absolute distance length in physics which is called Planck length which doesn’t scale up or scale down; so, it’s a little fact that often gets missed when you talk about being able to transform any length into any other length depending on the reference frame, but the Planck length doesn’t. I know there are some variation of Special Relativity and something I think they call doubly Special Relativity [inaudible] but they do involve absolute distance lengths.

DR. CRAIG: I am not familiar with that nor have a read Smolin’s book so I can’t comment. Thank you.

QUESTION: You said that in absolute time the universe is, or is like, God’s clock. How does that work? How could there be a single clock in the universe that we know? [39]

DR. CRAIG: As the universe expands there is a kind of natural geometry in which the universe is homogeneous and isotropic, and you can then establish a cosmic time parameter that will measure the proper time of the duration of the universe back to its beginning. And it’s important to understand this is not a coordinate time, time is a parameter here that is independent of spatial coordinates. So it is not part of the spacetime coordinates of events; this is a parameter which is independent of spatial coordinates and gives you how long the universe has existed. So when people say the universe is 13.7 billion years old, they are not talking about earth time, they are talking about comic time and this is the same for every observer in the universe regardless of his state of motion. The universe in cosmic time is about 13.7 billion years old and my suggestion is that that would be the natural measure of how long it’s been since God created the world. So what could be clearer than that? For God, it was 13.7 billion years ago that he created the world and that the universe is, in effect, a clock measuring how long it’s been.

FOLLOWUP: Where do we get these units in years?

DR. CRAIG: Those would be arbitrary, obviously; that is a convention but we get it from the earth’s orbital motion around the sun. The interesting thing is that the earth is very nearly at rest with respect to the microwave background radiation which seems to coincide with this cosmic time. So we actually have a pretty good idea of what time it is in cosmic time. The earth is slowly moving in the direction of the constellation Leo (by, I think, 360 kilometers per second or something like that) so that we actually have a pretty good measure of cosmic time by using our clocks here on this planet. It is quite remarkable.

QUESTION: On your view that there is a preferred frame which God is sensitive to but which we cannot identify, is that not itself somewhat surprising? Why should it be hidden from us in this way?

DR. CRAIG: Well, I don’t see any reason to think that if there is this sort of preferred frame that it would need to disclose itself to us. In fact, these deformations are necessary in order to maintain the equilibrium of systems in motion, so that they are not destroyed. So the hiddenness of the preferred frame, in a sense, could be an indication of the providential care of God. It is due to these sorts of deformations that physical objects are able to maintain their internal equilibrium. But, in cosmic time, there I do think that this preferred time is revealed. Because of the expansion of the universe we are able to detect what time it really is. It is remarkable how the old classical ether has come back into modern physics under new guises; for example, I’ve already mentioned the microwave background radiation which is the microwave equivalent of the luminous ether of the 19th century and we can actually detect the ether wind of our motion through the microwave background radiation. The quantum mechanical vacuum is also like a modern ether that coincides with this, and the preferred frame of expanding space. So there are quite a number of these sorts of ether-frame-equivalent notions in modern physics that do give us a good idea of what time it really is. So I don’t think that nature is conspiring to conceal this from us.

QUESTION: What happens to God and time when one encounters a black hole, and approaches a singularity? [40]

DR. CRAIG: Right. The deviations from cosmic time that occur are due to either local gravitational effects or the type of motion that comes into view in the Special Theory of Relativity. So cosmic time would define a kind of worldwide parameter that would measure the proper time of the universe; but locally, as in black holes, this will become distorted because of gravitational effects. So Wheeler, Thorn, and Misner in their book on gravitation describe cosmic time as many-fingered. When you get into these black hole areas it is like fingers, so to speak, in cosmic time so that at the end of a black hole that is the end of the universe there – it is the end of time. So I am talking about these broad hyper-surfaces globally that represent cosmic time. But you’re quite right in saying that with black holes and other local phenomena you would not have cosmic time registering this sort of global parameter. The deviations from cosmic time would be due to just local phenomena so relativity is reducible to local phenomena, not a global one.

QUESTION: I would like to press you on this idea that the universe could be God’s clock. Now, of course, if you go back towards the time when the microwave background radiation was created then you can actually measure the passage of years; in our civilization they measure the passage of time by the oscillations of cesium atoms. What do you do when the universe is the size of a cesium atom? Ultimately, all your clocks are going down with you into the singularity, so, how do you solve this?

DR. CRAIG: Well, ultimately this will break down, as you say, when you get back before the Planck time. Then you are not going to have any sort of physical mechanism that is going to operate but I don’t think that means that time itself ceases to exist. It just means that you won’t have a clock at that point; I think you’re quite right about that.

QUESTION: I have a good feel now for your reasons for preferring Lorentz’s approach to spacetime than Einstein’s from 1905. If you were to compare the approaches to spacetime we get from Minkowski in 1908 and 1909, I don’t have a complete understanding as to why you prefer the old Lorentzian approach other than the fact that it is more compatible with the view that you presented on God’s relation to time. Do you have any other reasons for preferring a Lorentzian approach?

DR. CRAIG: Well, my main reason is because I am just so deeply committed to a so-called A-theory of time, a tensed theory of time. In fact, I think that what really carries the water in this argument isn’t so much God, as the tensed theory of time. Because if temporal becoming is an objective feature of the universe that is mind independent then it is simply not true that all events in spacetime are equally real, or on an ontological par. And there are all sorts of other deleterious consequences to spacetime realism. I think it implies, for example, perdurantism with respect to personal identity over time. I am literally not the same person that walked into this room this morning; I am a later temporal stage of a four-dimensional worm but not the same as the earlier stage. And this has all kinds of crazy consequences for personal identity, moral responsibility, and so forth. So, in my book, again, I lay out my best case against the tenseless theory of time and hence this Minkowskian spacetime realism which presupposes it, as well as thinking there is no good reason to adopt such a breathtaking metaphysic of the world as to think that our experience of temporal becoming is an illusion and that all events, whether past, present, or future, are equally real. It seems to me that that is a gratuitous reification of a diagram in which space and time are plotted together on a piece of paper but there is no reason to invest that diagram with actual reality. [41]

  • [1]

    William Lane Craig, The Tensed Theory of Time: A Critical Examination, Synthese Library 293 (Dordrecht: Kluwer Academic Publishers, 2000).

  • [2]

    William Lane Craig, The Tenseless Theory of Time: A Critical Examination, Synthese Library 294 (Dordrecht: Kluwer Academic Publishers, 2000).

  • [3]

    William Lane Craig, God, Time and Eternity (Dordrecht: Kluwer Academic Publishers, 2001).

  • [4]

    William Lane Craig, Time and Eternity: Exploring God’s Relationship to Time (Wheaton, IL: Crossway, 2001).

  • [5]

    William Lane Craig, Time and the Metaphysics of Relativity, Philosophical Studies Series 84 (Dordrecht: Kluwer Academic Publishers, 2001).

  • [6]

    Isaiah 57:15 (RSV).

  • [7]


  • [8]


  • [9]

    Isaac Newton, Sir Isaac Newton’s ‘Mathematical Principles of Natural Philosophy’ and his ‘System of the World,’ trans. Andrew Motte, revised with an Introduction by Florian Cajori (Los Angeles, CA: University of California Press, 1966). vol. 1, p. 6.

  • [10]


  • [11]

    Ibid., vol. 2, p. 545.

  • [12]

    J. E. McGuire, “Newton on Place, Time, and God: An Unpublished Source,” British Journal for the History of Science, 11 (1978): p. 123.

  • [13]


  • [14]

    Gerald Holton, “On the Origins of the Special Theory of Relativity,” in Thematic Origins of Scientific Thought: Kepler to Einstein (Cambridge, MA: Harvard University Press, 1973), p. 171.

  • [15]

    See esp. the writings of Gerald Holton, in particular “Mach, Einstein, and the Search for Reality,” in Ernst Mach: Physicist and Philosopher, ed. Robert S. Cohen and Raymond J Seeger, Boston Studies in the Philosophy of Science 6 (Dordrecht: D. Reidel, 1970), pp. 165-99; “Where is Reality? The Answers of Einstein,” in Science and Synthesis, ed. UNESCO (Berlin: Springer-Verlag, 1971), pp. 45-69; and the essays collected in Thematic Origins of Scientific Thought: Kepler to Einstein (Cambridge: Harvard University Press, 1973).

  • [16]

    Einstein, “On the Electrodynamics of Moving Bodies,” tr. Arthur I. Miller, appendix to Arthur I. Miller, Albert Einstein’s Special Theory of Relativity (Reading: Addison-Wesley, 1981), p. 392.

  • [17]

    Ibid., p. 393 (my italics).

  • [18]


  • [19]

    Einstein, Über das Relativitätsprinzip [1907], p. 417.

  • [20]

    Einstein, Über die Entwicklung unserer Anschauungen [1909], p. 819.

  • [21]


  • [22]

    Einstein, Relativitäts-Theorie [1911], p. 9 (my translation).

  • [23]


  • [24]

    Ibid., p. 11.

  • [25]

    Albert Einstein, Relativity, the Special and the General Theory, trans. Robert W. Lauren (London: Methuen, 1920), p. 26.

  • [26]

    Albert Einstein, The Meaning of Relativity, 6th ed. (1922; rep. ed.: London: Chapman and Hall, 1967), p. 2. Cf. his “Fundamental Ideas and Problems of the Theory of Relativity,” [1923], in Nobel Lectures, Physics: 1901-1921 (New York: Elsevier, 1967), pp. 479-490, where he lays down a postulate called “the stipulation of meaning,” which requires that concepts and distinctions are only admissible to the extent that observable facts can be assigned to them without ambiguity. He considers this postulate to be of “fundamental importance” epistemologically.

  • [27]


  • [28]

    See the excellent survey in Frederick Suppe, “The Search for Philosophical Understanding of Scientific Theories,” in The Structure of Scientific Theories, 2nd ed., ed. F. Suppe (Urbana, IL: University of Illinois Press, 1977), pp. 3-118. Verificationism was far too restrictive a theory of meaning to be plausible, for it would force us to dismiss as meaningless vast tracts of human discourse, including not just metaphysical and theological statements but also aesthetic and ethical statements, as well as many scientific statements (e.g., the postulate of the constancy of the one-way velocity of light, an unprovable assumption which lies at the heart of STR). Worse, verificationism turned out to be self-refuting. For the statement “Only sentences which can in principle be empirically verified are meaningful” is itself not an empirically verifiable sentence and so is by its own standard meaningless!

  • [29]

    Henri Poincaré, “The Measure of Time,” in The Value of Science, 1905, trans. G. B. Halstead, in The Foundations of Science (Science Press, 1913; rep. ed.: Washington, D.C.: University Press of America, 1982), p. 228.

  • [30]


  • [31]

    Ibid., pp. 228-9.

  • [32]

    H. A. Lorentz to A. Einstein, January, 1915, Boerhaave Museum, cited in Jozsef Illy, “Einstein Teaches Lorentz, Lorentz Teaches Einstein. Their Collaboration in General Relativity, 1913-1920,” Archive for History of Exact Sciences 39 (1989), p. 274.

  • [33]

    J. N. Findlay, “Time and Eternity,” Review of Metaphysics 32 (1978-79), pp. 6-7.

  • [34]


  • [35]

    John Kennedy in a paper delivered to the American Philosophical Association, Central Division Meeting, Pittsburgh, PA, April 23-26, 1997. Compare the passing remark of Balashov, “the idea of restoring absolute simultaneity no longer has a distinctively pseudo-scientific flavor it has had until very recently” (Yuri Balashov, “Enduring and Perduring Objects in Minkowski Space-Time,” Philosophical Studies 99 (2000), p. 159).

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