By Andrew Brenner

Winner of the Gerritt and Edith Schipper Undergraduate Award for Outstanding Undergraduate Paper at the
55th Annual Meeting of the Florida Philosophical Association

Andrew Brenner, University of North Florida

In this essay I explore the thought of Thomas Aquinas as it relates to time, and specifically as it relates to the reality of tense and temporal becoming. In short, the question posed here is: did Aquinas advocate, intentionally or unintentionally, what we would now call an A-theory of time, or a B-theory of time?

The A-theory is no doubt the “common sense” view of time. The present is all that exists. The past did exist, the future will exist, but neither of them exist now. Alan Padgett writes that

for the [A-theory], the fundamental nature of things is dynamic, and undergoes changes in ontological status. The world is made up of three-dimensional objects which constantly change, come into being, and go out of being. Only the present episode of an object exists, period. There is no sense in which future episodes exist “tenselessly.” 1

Alternatively, advocates of the B-theory assert that the “flow of time” is illusory. Objects do exist tenselessly, and the only temporal relations between them are the relations of “before,” “after,” and “simultaneous with.” Thus all objects and events are on an ontological par, whether we think of them as past, future, or present. The “transiency of the now” (i.e., the “flow of time”) is a mental illusion.

The distinction between the A-theory of time and B-theory of time is generally recognized as an important part of the debate over the sense in which one should construe God’s eternality. William Lane Craig writes: “What is clear is that the doctrine of divine timelessness stands or falls with the [B-]theory of time. The [B-]theory of time is the metaphysical presupposition of divine timelessness.” 2 And Richard Creel summarizes the issue: “In brief, either a thing is changing or it is not. If God does not know it is changing but we know it is changing, then one of us is mistaken, and it surely is not God.” 3 In the B-theory of time, however, change really is an illusion, so there’s nothing in Creel’s statement to worry the proponent of divine timelessness within that theoretic

presupposition. While it would be interesting to explore in more detail the kind of argument offered here by Creel, I’m going to restrict myself to one question: Did Aquinas believe in the “transiency of the now”? In other words, for Aquinas, is the present the only thing that exists, or are all times on an equal ontological footing? To begin to answer this question it will be helpful to survey a representative sample of Aquinas’s views on the nature of time, as well as God’s relationship with time.

Aquinas writes:

  1. Now God knows all contingent things not only as they are in their causes, but also as each one of them is actually in itself. And although contingent things become actual successively, nevertheless God knows contingent things not successively, as they are in their own being, aswedo;butsimultaneously.Thereasonisbecausehisknowledgeismeasured by eternity, as is also His being; and eternity being simultaneously whole comprises all time, as said above [Q. 10, A.2]. Hence, all things that are in time are present to God from eternity, not only because He has the types of things present within him, as some say; but because His glance is carried from eternity over all things as they are in their presentiality. 4
  2. …God sees all things in His eternity, which, being simple, is present to all time, and embraces all time. 5
  3. With like certitude God knows, in His eternity, all that takes place throughout the whole course of time. For His eternity is in present contact with the whole course of time, and even passes beyond time. We may fancy that God knows the flight of time in His eternity, in the way that a person standing on top of a watchtower embraces in a single glance a whole caravan of passing travelers. 6
  4. Although a contingent does not exist as long as it is future, as soon as it is present it has … existence… 7

The most salient feature of these passages in regard to God’s relationship with time is that God’s eternity is not only beyond time, but somehow embraces all time as well. The ontological distinction between past, present, and future is nullified. All are present at once (metaphorically speaking) to God’s timeless gaze. Thus, God “knows the flight of time in His eternity, in the way that a person standing on top of a watchtower embraces in a single glance a whole caravan of passing travelers,” as was quoted above. It seems incomprehensible to suggest that, though God’s omniscient “single glance” and omnipotent power are present to all times, with no ontological distinction between them, yet only the presentis actual. And yet, Aquinas also seems to endorse temporal becoming in quotes 1 and 4 above. For example, part of quote 1 reads “although contingent things become actual successively, nevertheless God knows contingent things not successively … but simultaneously.” This apparent conceptual tension has been noted by some interpreters of Aquinas. Craig, in his aptly titled essay “Was Aquinas a B-Theorist?” writes:

…I find it inconceivable that he consciously adhered to [the B-theory of time]. For him becoming was not mind-dependent, but real, and it was only because of God’s eternal being that all things were present to Him. Aquinas seemed to hold both to a dynamical view of time and to the actual existence of all temporal things for God in eternity. Despite this, however, I must admit that I can only make sense of Aquinas’s position on God’s foreknowledge and future contingents by interpreting him as proponent of the B-theory of time. 8

Should one concur with Craig on this point, that despite the apparent contradictions in Aquinas’s thought he should ultimately be read as a B-theorist? I find myself compelled to agree with this interpretation of Aquinas. The most sympathetic reading of the relevant texts, especially Aquinas’s commitment to God’s simultaneous presence to all times, forces me to see Aquinas as an inadvertent proponent of what is fundamentally a B-theoretic conception of time. To avoid contradiction Aquinas would probably most easily concede that temporal becoming and the apparent passage of time are merely how things appear to us, but that God in His eternity perceives the true nature of reality. Indeed, given the central place of divine simplicity, and thus immutability, in Aquinas’s thought, from which divine timelessness follows, I find it hard to imagine Aquinas resolving the apparent conceptual conflict in any other way, especially in a rejection of divine timelessness. On top of that Aquinas’s proposed solution to the problem of divine foreknowledge of future contingents makes exclusive appeal to the way he has formulated God’s relationship to time, from which the B-theory seems to follow.

Though this reading of the texts seems plausible enough several philosophers have tried to reconcile Aquinas’s account of God’s eternity with the A-theory of time. It is to these that I now turn. Unfortunately, I do not have space to give the detailed responses these philosophers’ proposals deserve. I will however, briefly describe what appears to me to be the flaw(s) in each of these proposals, in the hopes that the reader will at least think these brief rebuttals plausible.

William Hasker, for example, concedes that it would be contradictory to assert that God, being timeless, directly experiences temporal things. Presupposing the A-theory of time, Hasker argues that a timeless God could still have knowledge of temporal things if those temporal things only “exist in eternity as represented in the mind of God.” 9 Hasker believes this position is endorsed by Aquinas, but it does not seem clear to me that it is. For example, Aquinas writes that “all things that are in time are present to God from eternity, not only because He has the types of things present within him, as some say; but because His glance is carried from eternity over all things as they are in their presentiality.” 10  For Aquinas God’s timeless knowledge of temporal things is a direct knowledge of temporal things in their actuality, not just representations of them in God’s mind.

Brian Leftow appeals to the relativity of simultaneity posited by some interpretations of Einstein’s special theory of relativity to provide an analogy to the way he interprets Aquinas’s views on time. Just as in (Leftow’s interpretation of) the special theory of relativity something may be actual in one reference frame but not actual in another, we should, analogously, treat eternity and time as separate frames of reference. While the future may not be real in time it is realin eternity.

An event occurs in eternity simultaneously with all other events, but this does not entail that event occurs simultaneously with all other events in any other reference-frame. Rather, in eternity, all events occur at once, and they occur in sequence in temporal reference frames. Events are present and actual all at once in eternity, but present and actual in sequence in other reference frames. 11

Since, of course, Aquinas couldn’t have known about the special theory of relativity one must assume that Leftow uses the analogy to blunt the conceptual trauma of such a bifurcated view of reality, in which what is real for us is not what is real for God. But surely, echoing Richard Creel, whom I quoted earlier, what is real for God is real simpliciter. If change is real, in time at any rate, and God is unable to experience it, His omniscience is missing out, so to speak. In any case, the analogy Leftow appeals to, that of the special theory of relativity, admits of multiple arguably more plausible interpretations, some of which do not carry the implications he needs to make his case. Indeed, these other interpretations are generally thought to be more plausible precisely because they do not posit such a fragmented and subjective ontology. 12

Alternatively, Kevin Staley defends the compatibility of the A-theory with divine timelessness in Aquinas by appealing to the absolute simplicity of God’s eternity. He writes:

What is important about the eternal knower is not a privileged perspective on reality that we lack; rather, it is that His knowing is not itself divided by time. Because his knowing is simple and partless, real succession in the object known does not give rise to succession in God’s knowledge of the known. 13

Furthermore, God’s eternal knowledge, Staley explains,
…requires only that the privileged actuality of the present when it is present be present to the whole of God’s simple eternity. And this it cannot fail to do, for it is impossible to be present only to a part of that which is without parts. God’s eternal knowledge of the temporal remains paradoxical; it would appear that although the future is not present to God, when it is present to Him, it will never be and will never have been absent from Him. 14

Staley seems to concede here that there really is a privileged Now and real temporal becoming. But if this is true, and the future really is not present yet to God’s eternity, as Staley says, how could God properly be said to have knowledge of future contingent propositions? Indeed, given Stanley’s solution God’s omniscience appears to be compromised. Despite what Staley says, namely that “what is important about the eternal knower is not a privileged perspective on reality that we lack; rather, it is that His knowing is not itself divided by time,” I would contend that one of the most important implications of Aquinas’s theory of divine timelessness really is God’s privileged perspective on reality that allows Him to know things that we cannot, particularly future contingent events “as each one of them is actually in itself.” 15  Staley’s attempt to reconcile divine timelessness with the A-theory is incompatible with this implication.

Staley also proposes that the content of reality available to God’s eternity changes, “yet it would appear that although the future is not present to God, when it is present to Him, it will never be and will never have been absent from Him.” 16 This proposal, however, is explicitly rejected by Aquinas, when he writes:

If, however, anything existed which God did not previously know, and afterward knew, then his knowledge would be variable. But this cannot be; for whatever is, or can be in any period of time, it known by God in His eternity. Therefore from the fact that a thing exists in some period of time, it follows that it is known by God from eternity. 17

Appealing to divine simplicity at this juncture, as Staley does, seems abortive, as divine simplicity is what prevents change in God in the first place, not what makes it true of something that was not, but now is, present to God that “it will never be and will never have been absent from Him” after the fact, i.e., after the change.

These proposals, designed to reconcile Aquinas’s theory of divine timelessness with the A- theory, don’t seem as promising as one would hope (or at least, I have so argued). I would like to note though that reading Aquinas as a B-theorist, besides, it seems, remaining true to the implications of the relevant passages, resolves at least two major difficulties with Aquinas’s account of divine timelessness.

First, there are powerful objections to the compatibility of divine timelessness and the A- theory of time that stem from God’s sustaining relationship with the temporal world and his changing knowledge of temporal indexicals. If, for example, the A-theory of time is correct and God continually sustains all logically contingent things aside from Himself (an attribute theists have traditionally attributed to God), then God must, for some transiently existing object, sustain that object at some times and not sustain it at other times, in contradiction with his absolute immutability. 18 Also, the conjunction of the A-theory with God’s omniscience seems incompatible with divine timelessness. 19 On the A-theory of time “since tensed facts are in constant flux, so must be God’s beliefs or cognitive state, which entails that God is temporal.” 20

Second, if Aquinas is read as a B-theorist he can easily defuse another one of the most common objections to the classical conception of divine timelessness: the objection from the transitivity of simultaneity relations. Anthony Kenny, for example, writes that

the whole concept of a timeless eternity, the whole of which is simultaneous with every part of time, seems to be radically incoherent. For simultaneity as ordinarily understood is a transitive relation. If A happens at the same time as B, and B happens at the same time as C, then A happens at the same time as C. …But, on St. Thomas’ view, my typing of this paper is simultaneous with the whole of eternity. Again, on his view, the great fire of Rome is simultaneous with the whole of eternity. Therefore, while I type these very words, Nero fiddles heartlessly on. 21

What Kenny fails to make clear here is his A-theoretic presuppositions. Given the A-theory of time’s commitment to the privileged Now, Kenny’s criticism is powerful. But given a commitment to a B-theory of time all temporal moments are ontologically concomitant, so there is nothing incoherent going on when Aquinas asserts that “God’s one glance is cast over all things which happen in all time as present before Him.” 22

So reading Aquinas as a B-theorist not only seems to be a rather inescapable implication of the relevant texts, but also undermines several otherwise powerful objections to divine timelessness. But this problem remains: any problems one finds with the B-theory will pass over into Aquinas’s treatment of time, particularly his treatment of God’s eternity. But God’s eternality (His timelessness) follows from His immutability, and His immutability follows from His simplicity. Divine simplicity in turn is the centerpiece of Aquinas’s conception of God, and consequently much of his philosophy of religion. Therefore, any intractable difficulties one finds in the B-theory could be fatal to many of Aquinas’s other philosophical and theological views.



  1. Alan G. Padgett, God, Eternity and the Nature ofTime (New York: St.Martin’s P, 1992) 5
  2. William L. Craig, God, Time, and Eternity (Dordrecht: Kluwer Academic, 2001) 137
  3. Richard A. Creel, Divine Impassibility (Cambridge: Cambridge UP, 1986) 96.
  4. Thomas Aquinas, Summa Theologica, Vol. 1, trans. Fathers of the English Dominican Province New York: Cosimo Classics, 2007) Q.14, A.13.
  5. Aquinas, Summa, Q.57, A.3.
  6. Thomas Aquinas, Compendium Theologiae, trans. Cyril Vollert (St. Louis: B. Herder Book Co., 1947) Chapter 133.
  7. Thomas Aquinas, De Veritate 2, 12 ad 9. Quoted in Brian Leftow, “Aquinas on Time and Eternity,” American Catholic Philosophical Quarterly 64 (1990): 388
  8. Reprinted in William L. Craig, The Problem of Divine Foreknowledge and Future Contingents from Aristotle to Suarez(London: E. J. Brill, 1988) 118
  9. William Hasker, God, Time, and Knowledge (Ithaca: Cornell UP, 1989) 168; original italics
  10. Aquinas, Summa, Q.14, A.13; italics added
  11. Leftow 392
  12. Obviously I do not have room in this essay to give detailed arguments in support of this claim. For an excellent exposition of the philosophical issues surrounding the proper interpretation of special relativity from a theistic perspective see William L. Craig, Time and the Metaphysics of Relativity (Dordrecht: Kluwer Academic, 2001). Craig 2001b and William L. Craig, “The Metaphysics of Special Relativity: Three Views,” in Einstein, Relativity, and Absolute Simultaneity, eds. William L. Craig and Quentin Smith (London: Routledge, 2008) 11-49
  13. Kevin M. Staley, “Omniscience, Time, and Eternity: Is Aquinas Inconsistent?” The Saint Anselm Journal 3 (2006): 26
  14. Staley 26
  15. Aquinas, Summa, Q.14, A.13.
  16. Staley 26.
  17. Aquinas, Summa, Q.14, A.15.
  18. See Padgett 74-81 and Craig, God, Time, and Eternity, Chapter 3.
  19. See Norman Kretzmann, “Omniscience and Immutability,” Journal of Philosophy 63 (1966): 409-21; Craig, God, Time, and Eternity, Chapter 4.
  20. Craig, God, Time, and Eternity, 112.
  21. Anthony Kenny, “Divine Foreknowledge and Human Freedom,” Aquinas: A Collection of Critical Essays, ed. Anthony Kenny (Garden City: Anchor Books, 1969) 264. This criticism is repeated in Anthony Kenny, The God of the Philosophers (Oxford: Oxford UP, 1979) 38-39. Richard Swinburne gives a very similar objection in The Coherence ofTheism (Oxford: Clarendon P, 1977) 220-21
  22. Aquinas, Summa, Q.57, A.3

Andrew Brenner