The problem and the Boethian solution

As traditionally conceived, the problem of divine foreknowledge and human freedom arises from an apparent incompatibility between God's essential omniscience, on the one hand, and a libertarian account of free will, on the other. Classical theism tells us not only that God knows everything that there is to know, but also that this property of omniscience is necessary to him; that is, that there is no possible world in which God is not omniscient. It is true, of course, that some contemporary theologians and philosophers of religion have questioned whether the classical conception of God – the God of the Philosophers, if you will – is compatible with the Judaeo-Christian God of the Bible. And though I am sympathetic with some aspects of this project – particularly when it comes to questioning such classical theistic properties as divine simplicity and impassibility – I will assume throughout this article that God's omniscience is unassailable: if God exists, then he must know everything that there is to know. Furthermore, I will assume that his knowledge includes propositions about the future free actions of human beings. So-called ‘open theists’ want to reject this assumption, and believe that they can do so without rejecting God's omniscience, by claiming that there are no such propositions to be known.Footnote ² On their view, since propositions about the future free actions of human beings do not exist, then God's not knowing them is still compatible with him knowing everything there is to know.

For my part, I find this approach to God's omniscience problematic for two reasons. First, if we are to reconcile our philosophical account of God's omniscience with biblical accounts (something that the open theists certainly take themselves to be doing), then we have to acknowledge that there are many instances in the Bible of God (and/or Christ) having knowledge of propositions about the future; and further, that some of these are specifically propositions about the actions of human beings (e.g. Christ's knowledge of Peter's future denials of himself). So in order to maintain the open theist conception of omniscience in light of the biblical evidence, we would have to claim that all such cases do not involve free actions, but determined ones. And while this claim may be plausible in certain cases (such as when God knows – seemingly on the basis of his intention to harden Pharaoh's heart – that Pharaoh will not let the Hebrews go), it would be a strained interpretation to see all such cases as ones of divine determination (especially in the context of reconciling omniscience and human freedom!).

Supposing, however, that we did accept such an interpretation. What, on this account, would God's knowledge of the future be like, and how would that knowledge allow for the providential role which he is meant to play in the lives of those who believe in him? The Apostle Paul tells us in Romans 8:28 that ‘all things work together for good to those who love God, to those who are the called according to His purpose’. Given the gappy foreknowledge that God would have to have if such knowledge was limited only to determined events and actions (again, assuming that most actions are not determined), it is not at all clear how Paul's encouraging statement could be true, nor how God could know it to be true. On the basis of these considerations, then, I will adhere to the classical conception of God's omniscience as including a complete knowledge of the future.

It follows from God's essential omniscience that he is also essentially infallible, that is, that his belief of any proposition p entails the truth of p.Footnote ³ Thus, if God believes at time t1 that an agent A will perform an action S at a later time t3, then A will perform S at t3. This is where the libertarian account of free will comes in. According to the libertarian, in order for an action to be free in her sense of the term, it must be possible, at the time of performing the action, that she refrain from performing the action. Thus, for an agent A to freely perform an action S at t3, she must be able to refrain from performing S at t3. And the worry, of course, is that God's believing that A will perform S at t3 entails that A is not able to refrain from performing S at t3. Again, there are those who will deny the libertarian account, and instead claim that all that is necessary for freedom of the will is the ability to perform the action, in accordance with one's desires, that one actually does perform. The theists who hold this compatibilist conception of free will are often referred to as Calvinists, after the sixteenth-century French theologian (though adherents of the compatibilist view go as far back as Augustine). The worry that libertarian theists have about Calvinism is the difficulty of reconciling God's justice with his condemnation of those who perform evil actions, when God is ultimately responsible for those actions, and thus seemingly responsible for the presence of evil in the world. There is also the further worry that human virtues such as love and creativity lose their value on a compatibilist conception of human freedom. As in the case of divine omniscience, I will assume the libertarian account of free will throughout this article.

Those are the general considerations that generate the dilemma between foreknowledge and freedom. Let's look now at a specific argument for theological fatalism, the form of which I take to be the most convincing. What makes it convincing is its reliance on the concept of the fixity of the past, a concept that is grounded in the intuition that the past is determinate, unalterable, and inexorable. So the argument grounds the fixity of the future in the fixed events of the past – namely, in God's past beliefs about the future. Thus, it is not merely present truth about the future that fixes the future, it is, rather, the occurrence of past events that fixes the future. This is what the argument looks like (assume the following: Susan goes to Anstruther at t3, t2 = the present, and t1 < t2 < t3):

1. (1) If Susan goes to Anstruther at t3, then God believed at t1 that Susan will go to Anstruther at t3. (from God's essential omniscience)

2. (2) God's believing p entails that p is true. (from God's essential infallibility)

3. (3) It is not within an agent's power to bring about a non-actual past state of affairs. (from the fixity of the past)

4. (4) Susan does not have it within her power to refrain from going to Anstruther at t3. (from (1), (2), and (3) )

   Therefore,

5. (5) Susan is not free with respect to going to Anstruther at t3. (from (4) )

The crucial premise here is (4), and it follows from the fixity and infallibility of God's past belief about Susan's future. In presenting the argument, I have chosen not to characterize the fixity of the past as a kind of necessity. This is because I don't think the argument requires such a characterization, and because I think that identifying fixity with the necessity operator of modal logic is fraught with problems.Footnote ⁴ It is sufficient to point out, as Nelson Pike does in his seminal article on this topic, the following ramifications of the fixity of God's past belief: In order for (4) (and therefore (5) ) to be false, Susan must have the power at t3 to either (i) make God's belief at t1 false, or (ii) make it the case that he didn't have the belief at t1, or (iii) make it the case that he didn't exist at t1 (see Pike (Reference Pike, Cahn and Shatz1982), 65–66). But given that t1 is in the past, Susan does not have any of these powers; for no-one has power over the past.

That, then, is the problem. The Boethian solution is to deny (1): God's beliefs are not in the past; rather, God and his beliefs are outside of time. So, technically, God does not foreknow anything, as there is nothing for him to foreknow. All the objects of God's knowledge are eternally existing, tenselessly true propositions, and so are not true at any time, but are true simpliciter. Thus, the Boethian can replace (1) with (1*):

Given that (1*) is not about the past, it is not fixed, and therefore is in Susan's power to make either true or false. This, of course, is not to claim that Susan can change the truth value of (1*); rather, the thought is that Susan makes it [tenseless] the case that she either goes to Anstruther at t3 or does not. So her action at t3 determines the eternal truth (or falsity) of the proposition. How can God know tenseless, eternally existing propositions about events in time? He can know them by observing all events in time as eternally present to himself. It is important to understand that God's eternal present is not a temporal one: it is not temporary and always changing. It is more like being ‘present to the mind’ rather than present tense. As Boethius states it, eternity is ‘the simultaneous and complete possession of infinite life’; and an eternal being ‘must be ever present in itself to control and aid itself, and also must keep present with itself the infinity of changing time’ (Boethius (Reference Boethius and Cooper1902), 160–161).

Stump and Kretzmann (Reference Stump and Kretzmann1981) have devised an ingenious model for making intelligible the idea that God sees all events in his own eternal present. They define a relation that they term ‘Eternal-Temporal (ET)-simultaneity’, and argue that this relation holds between God and the temporal world. The relation, more specifically, holds between eternal and temporal entities, where these are observed to be either ‘eternally present’ (in the Boethian sense) or ‘temporally present’ by an observer in either the eternal frame of reference, or an observer in one of the many temporal frames of reference. So when God, from the unique eternal reference frame, observes as present an event in one of the infinitely many temporal reference frames, his observation is ET-simultaneous with that event. Furthermore, the definition Stump and Kretzmann offer entails that all temporal events are ET-simultaneous with God's eternal reference frame (ibid., 439). In this way, God can eternally observe all events as present to himself; in which case, his beliefs about those events are never past, and therefore neither the events which such beliefs figure in, nor the events which they are about, are fixed.

Objections

There have been a whole host of objections raised against the Boethian solution and Stump and Kretzmann's refining of it. Generally speaking, these objections fall under three types: (i) those which have to do with the broader implications of the Boethian solution for divine eternity and the nature of time; (ii) those which claim the solution fails even on its own terms, quite apart from the implications of those terms; and (iii) those which object specifically to the coherence of the concept of ET-simultaneity, as well as to Stump and Kretzmann's employment of that concept in defending the Boethian solution. In this subsection I will consider objections falling under types (i) and (ii), but not those falling under type (iii). The reason for this omission is that the discussion of the other objections will lead me away from the perceptual model of the traditional Boethian solution, and towards a non-perceptual model in which the concept of ET-simultaneity has no application (though we will see that a concept analogous to that one will prove applicable).

The first objection I will consider (falling under type (i) ) is that the Boethian solution implies eternalism, the doctrine that the past, present, and future eternally exist and are thus equally real. The concern is that if God can observe all events in time from his eternal perspective, and if his beliefs about those events are tenselessly true, then it would seem to follow that the events themselves must also exist eternally. Eternalism is one of the key tenets of the B-Theory of time, and so if the Boethian solution does imply eternalism, then embracing that solution might also involve endorsement of some kind of B-Theory.Footnote ⁶ Before considering whether the implication of eternalism by the Boethian solution constitutes an objection to that solution, we had better first consider whether the solution really does carry such an implication.

Does the Boethian solution imply temporal eternalism? Zagzebski is one philosopher who rejects the implication. She argues that the question of whether, for example, future events are real, does not even arise for an eternal being, since he sees them not as past, present, or future, but only as eternally present. So even if presentism – the version of the A-Theory that says only present events exist – is true, and future events are non-existent from the temporal observer's perspective, they can still be observed by God as existing from the eternal perspective. The plausibility of this claim rests upon Zagzebski's construal of the debate between the A- and B-theories. She says that ‘the A- and B-theories are competing theories about the status of events in some temporal observer's future’ (Zagzebski (Reference Zagzebski1991), 48). Thus, according to Zagzebski, philosophers of time are only interested in the nature of time from the temporal perspective (or, as she says elsewhere in this passage, the ‘temporal mode of existence’ (ibid.) ).

But is this really the proper construal of the A-Theory/B-Theory debate? It strikes me that it is not. Philosophers of time, as contemporary metaphysicians, take themselves to be arguing fundamental questions about the nature of the world and all that is in it – temporal or otherwise. An example of such a question is, ‘In the most unrestricted and general sense of the word “exist”, do future events exist?’ So the question is not whether the future exists from our perspective, as temporal beings; but whether it exists simpliciter. As a matter of fact, both presentists and eternalists are quite clear that the sense of ‘existence’ they are using in their arguments is existence simpliciter. There may, of course, be different modes of existence – temporal and eternal, spatial and non-spatial, abstract and concrete, for example – but it is normally agreed by those working on these questions that the existential quantifiers that feature in their claims are maximally unrestricted. On this approach to ontology, if God, angels, propositions, persons, and tables are all real, then they are all equally real; even though they may have different modes of existence. Not only is this the approach that those engaging in the A-Theory/B-Theory debate take, it is also, on my view, the correct approach.Footnote ⁷ Given that approach, I agree with those who believe that the Boethian solution implies eternalism, since if actual events that are future (future, that is, from the temporal perspective) exist at all, whether in the temporal or eternal mode, then they exist simpliciter. And on the Boethian solution, they must exist, since otherwise they could not be observed by God.

So the Boethian solution implies eternalism, and eternalism often goes hand in hand with the B-Theory, but does any of this count against the solution? Are there good reasons for the theist to reject eternalism and the B-Theory? Well, the B-Theory is based on the scientific conception of time as a four-dimensional block universe and stands in opposition to the A-Theory, which is often considered the ‘common sense’ view of time; so given that many theists tend to be more sympathetic to common sense than to what they might perceive as a scientistic approach to knowledge, many theists also tend to be A-Theorists (there are, of course, notable exceptions).Footnote ⁸ A further concern often cited by theists, particularly those of the libertarian stripe (recall that libertarianism is required to motivate the current debate), is that eternalism and the B-Theory cannot sufficiently ground a robust conception of freedom.Footnote ⁹ These, however, are both controversial objections to eternalism and the B-Theory, and I do not wish to get bogged down in such controversies in assessing the Boethian solution. The issue of whether there might be some version of the Boethian solution which is available to the A-Theorist, should, I hope, be one of interest to any party to the debate. So what I take from this particular objection is not that the Boethian solution fails, but that an endorsement of it by an A-Theorist calls for a modification of the traditional solution, in view of its eternalistic implications. It is the purpose of this article to provide such a modification.

Another objection to the Boethian solution, also falling under type (i), is to claim that a timeless God would be unable to know fundamentally tensed truths, such as the truth about what is happening now.Footnote ¹⁰ This worry is closely related to an objection that A-Theorists allege against B-Theorists, to the effect that sentences expressing tensed propositions cannot be translated into sentences expressing tenseless propositions – without loss of meaning. This aspect of the debate between A-Theorists and B-Theorists has to do with tensed language and whether there is anything in the world that corresponds to such language. The B-Theorist, inasmuch as she rejects the objective reality of distinctions between past, present, and future, claims that there is nothing in reality – apart from the subject's experience – that corresponds to tensed language. She must, therefore, be able to reduce tensed sentences to time-indexed tenseless ones; and the claim (the truth of which is now widely acknowledged by B-Theorists) is that she is unable to complete this reduction without losing some aspect of the meanings of the original tensed sentences.

This point relates to God and his alleged timelessness because a timeless being has nothing in its own existence which corresponds with a temporally dynamic world – and thus with the distinctions of past, present, and future. So if God were timeless, the tenseless propositions that he knows would fail to capture fully the meanings of the tensed propositions that we know; and thus he would lack knowledge of a fundamental feature of reality. This, of course, assumes that tense is a fundamental feature of reality, something that the B-Theorist denies. So the proponent of a timeless God is presented with a dilemma: either God's knowledge is lacking, or the A-Theory is false. Suppose, however, that one were to endorse the B-Theory on the basis of God's timelessness and in order to preserve his omniscience. This response still fails to address the concern that our experience of the world, whether veridical or not, is dynamic, and the language we use to talk about our experience is tensed; so even on a B-Theoretic view, there would be facts about us, as subjects of temporal experience, that God would be unable to know.Footnote ¹¹ If, however, God is – in some sense – a temporal being, then there is no additional mystery about his knowledge of, and interaction with, the created temporal world.Footnote ¹² Thus, it is my goal to provide a modified Boethian solution which not only coheres with an A-Theory of time, but which also entails that God is everlasting, rather than timeless.

The final objection to the Boethian solution that I wish to consider falls under type (ii), and so it argues that the so-called ‘solution’ simply does not work. The objection I have in mind is due to Zagzebski, and is dubbed the ‘Timeless Knowledge Dilemma’ by her. According to Zagzebski (Reference Zagzebski1991, 61–63), even if we claim that God's beliefs are eternal and therefore never past tense, we can still construct a parallel argument to the type of argument I presented earlier, resulting in the same fatalistic conclusion. This is because we have every reason to suppose that the fixity which would pervade God's past beliefs if he were in time would also pervade his eternal beliefs if he were timeless. Thus, if we replace

with

then we should also replace

with

Zagzebski calls this the Timeless Knowledge Dilemma (TKD), the thought being that God's eternal beliefs would be just as fixed as would his past-tense beliefs.

Is Zagzebski correct in making this claim? This, I think, depends on the metaphysics underlying the relationship between God's beliefs about future human actions and those actions themselves. Recall the first desideratum for a solution to the dilemma, which I specified in the Introduction: a successful solution must provide the metaphysical framework for a positive account of why truth about the future, and, specifically, God's knowledge of that truth, does not fix the future. Implicit in this desideratum is the following point: though we all wish to say that it is the ontology (in this case, future human actions) that determines or conditions the truth (i.e. truth depends upon being in a way that being does not depend upon truth), we cannot simply assert this seemingly obvious truth in this context. To do so is to beg the question against the fatalist, since this is precisely the claim that the fatalistic argument is meant to call into question. In the case of theological fatalism, the underlying metaphysics which is supposed to explain the counter-intuitive dependence of ontology upon truth is that God's beliefs are grounded in himself, rather than in the events which they are about. That is to say, God knows what we will do in the future because he is the author of what we will do. Thus, in this context, if we are going to assert the one-way dependence of truth upon events, then we have to offer a plausible alternative metaphysical picture that makes this dependence possible.Footnote ¹³

God's eternal beliefs being formed on the basis of his observation of our future (from our perspective) actions is one such alternative picture. Thus, according to the Boethian solution, it is not merely the case that God's beliefs are not past tense, but also that those beliefs are grounded in the events which they are about. Given, then, that the ontological ground of God's eternal knowledge is the event which is the object of his knowledge, rather than himself, I find no justification for the claim that his eternal knowledge is fixed. It is important to realize that this metaphysical picture is not available if God's beliefs are past tense, given that there is no plausible metaphysical picture which allows God's past beliefs to be grounded in future events.Footnote ¹⁴ Of course, in claiming that the Boethian metaphysical picture avoids Zagzebski's TKD, I am assuming that the Boethian solution implies eternalism (a claim for which I argued above). If, however, we allow that God might observe events from the eternal realm which do not exist in the temporal realm (as Zagzebski urges), then it is less clear how God's beliefs could actually be grounded in those non-existent events rather than in God himself. If the latter is the case, then the TKD does indeed threaten. I conclude, therefore, that the TKD is only a concern if one rejects the eternalistic implications of the Boethian solution, and I have already argued against that rejection. Nonetheless, given that I will be presenting a Boethian solution that is modified in order to accommodate divine temporality and the A-theory of time, we will need to bear in mind the TKD and ensure that the modified solution does not fall foul of it.

Modified Boethian solution

In spite of the objections to the Boethian solution, given the nature of the problem under consideration, inasmuch as it depends on premises like

it strikes me that some kind of Boethian solution must be right. That is, a successful solution must allow for a denial of (1). My goal in this section will be to devise a solution that allows for that denial, but in such a way that does not imply eternalism and a timeless God.

Fortunately, there is just such a solution to hand, but it rests on some prima facie counter-intuitive claims. Nonetheless, I hope to show that any impropriety in these claims is due to conventional prejudice, and can be satisfactorily dispelled by a consideration of the unconventional relation between time and eternity.

The challenge, then, is to be able to affirm consistently that

without thereby implying either

or

I think the only way to avoid (8), and thereby deny premise (1) of the theological fatalist's argument, is to adopt the same strategy that the Boethian does; that is, by replacing (1) with

I said that my solution was a modified Boethian solution, and this is the sense in which it is still Boethian. It claims that God's knowledge of the future free actions of agents is constituted by knowledge of tenseless propositions about those actions. Thus we now have (7) and

Now, what modification would I propose to avoid the implication of (9) by (7) and (8*)? Given my view of time, the future does not exist, and therefore the following obtains:

And given my earlier arguments, a non-existent (simpliciter) future cannot be observed from any vantage point, so (9) is effectively ruled out by (10). But now it becomes clear that, on my modified Boethian solution, the challenge is to explain how (8*) is compossible with (10). How can there be tenseless truths about dynamic events that have not yet come into existence? The right way to answer this question is to claim that though temporal reality is fundamentally dynamic, truth is not. Thus, there are eternally existing, tenseless propositions, with determinate truth values; but these propositions are made true by events that come into existence, and are not, themselves, eternal. So God's knowledge of the future is not perceptual, it is eternal, propositional, and purely conceptual; and it does not constrain our freedom because the truthmakers for the propositions that constitute God's knowledge of the future are those propositions' corresponding events, which come into existence as time passes. Furthermore, on this conception of divine eternity, though God has conceptual knowledge of tenseless propositions, he himself is everlasting (i.e. always existing), and therefore not timeless.

It is important to stress on this solution, however, that although God is temporal, he transcends our time. If this were not the case, then even though the proposition expressed by ‘Susan goes to Anstruther at t3′ is tenseless, God's act of believing that tenseless proposition would exist in our past; and thus the fatalist worry would remain. If we assert, however, that God's time, though related to ours, is not governed by the same metric (nor, indeed, any metric), then this worry does not arise, since God's beliefs would not be in our past. It is helpful in this context to refer to Padgett's (Reference Padgett1989) distinction between measured, empirical time, which is governed by the laws of nature and in which God need not exist; and the transcendent time of God, which has no metric and does not subject God to the negative aspects associated with the passage of measured time. This distinction allows that God can experience duration and succession in his being, without that experience depending upon the contingent existence of measured time, and without it being bound by the limitations of physical laws which determine the measure of time as we know it. On this plausible conception of divine temporality, divine time is not governed by any metric, so there is no sense in which God's acts of believing such propositions as ‘Susan goes to Anstruther at t3′ are in our past.

Problems

The problems with the solution outlined above will not require a great deal of introduction. They will be readily apparent to any philosopher trained to respect two venerable principles of contemporary analytic philosophy: (1) the claim that truth supervenes on being; and (2) Quine's dictum that ‘to be, is to be the value of a bound variable’. The first of these principles concerns correspondence between truth bearers and the world, and the second concerns the ontological commitments that are either explicit or implicit in one's theory. However, in the context of my modified Boethian solution, they are really two sides of the same problem. My solution apparently violates the conventional wisdom regarding both of these aspects of ontology, the first by suggesting that propositions can be true without any corresponding ontology, the second by suggesting that we can allow quantification over non-existent events. So the first problem arises from a scepticism about the truths, given the ontology (or lack thereof); the second arises from a scepticism about the ontology, given the truths. Thus, although the two problems are merely different sides of the same problem, I believe they deserve individual treatment. I will start with the problem from the supervenience of truth on being.

Does my solution force me to deny that truth supervenes on being? Making such a denial is one way to defend truth about a non-existent future. One can simply claim that such truths are brute, ‘free floating’, and not grounded in ontology in any substantive way.Footnote ¹⁶ This explanation, however, would be inconsistent with my statement of the solution, since I am claiming that propositions about future events are tenselessly true in virtue of those events coming into existence. And, in any case, I do not wish to deny that truth does, indeed, supervene on being; my claim is simply that it does so in an unconventional manner.

Perhaps, then, my view is that there is some kind of retrocausation taking place between an agent's actions and God's knowledge of those actions? This is another solution to the problem of theological fatalism that is sometimes proffered.Footnote ¹⁷ The thought would be that God's past knowledge of Susan's going to Anstruther in the future is caused by Susan's going to Anstruther – when she does so. Thus Susan's free actions cause God to always have known (or believed) that she would go to Anstruther at t3. No. In my view, such an example of retrocausation is as metaphysically suspect as is the existence of brute truths. What is true depends upon what exists, and the occurrence of future events cannot cause knowledge of past truths (nor cause past propositions to change their truth values). Furthermore, this solution is also inconsistent with mine, since I am denying that the relevant truths are ‘past’ in any sense: they are tenselessly true, and God's knowledge of them is eternal and unchanging.

So what conception of the relation between truth and being does my solution imply, and how is such a conception possible? Here is the idea. First, let's adopt the following general account of the principle that truth supervenes on being (TSB):

But I think everyone would acknowledge that we can identify at least two, more specific versions of TSB, depending on whether one takes language and time to be fundamentally tensed and dynamic or not. Thus we have:

In the case of E-TSB, the eternalist, tenseless theorist claims that there is nothing corresponding to the concepts of truth and existence at (or as of) a time. Tenseless propositions are true or false simpliciter, irrespective of the time at which they are considered. This is not to deny, of course, that such propositions are time-indexed – they certainly are. It is just to claim that time-indexed propositions, if true, are tenselessly true. Similarly, these propositions correspond to events that exist simpliciter. They are not true in virtue of events coming into existence at a time: all events exist eternally (again, even though located at times). Thus, according to E-TSB, it makes no sense to claim that there might be an eternal, tenseless truth about an event in time, without the corresponding event actually existing simpliciter. In contrast to E-TSB, the tensed, dynamic theorist claims that T-TSB is the proper version of TSB: propositions change in truth value depending on the time at which they are considered; and this is because existence is time dependent. The latter claim can be cashed out in various ways by the dynamic A-Theorist, but invariably what grounds time-dependent existence is the constantly changing objective present. And, from the perspective of T-TSB, it would make no sense to claim, for example, that a proposition about an event in time might be true now, without that event existing now.

So, given that when one asserts TSB, one normally has in mind one of these two versions of the thesis, it is understandable why my solution might be accused of violating TSB: I am claiming that there are eternal, tenselessly true propositions about events that have not yet come into existence. Clearly, then, what my solution requires in order to avoid violating TSB is a third version of the thesis. Here is my suggestion:

Now, one question about ET-TSB is whether it is even coherent; another is whether my modified Boethian solution is able to avoid violating it. I will take these questions in reverse order. First, as a general principle, TSB is often used to detect ontological ‘cheats’; that is, those whose theories postulate a certain set of truths, but do not postulate any corresponding ontology. Thus TSB (specifically, T-TSB) is used as an objection to the dynamic theory of time known as presentism. Presentism says that the only things (objects, events, times) that exist are present things. But presentism also says that there are truths at least about the past, if not also the future. Consider, therefore, the claim that ‘The Battle of Waterloo occurred in 1815′. This claim, according to the presentist, is true. So now the question is, given what exists (presently – since that is the only kind of existence according to presentism), could the claim ‘The Battle of Waterloo occurred in 1815′ possibly fail to be true? And, unfortunately for the presentist, it could indeed fail to be true, since there is nothing that exists that requires it to be true. It is for this reason that some presentists, such as Merricks (Reference Merricks2007), claim that truth need not involve any substantive dependence relation between truth bearers and what exists.

How, then, does my modified Boethian solution fare with respect to ET-TSB? Well, take any hypothetical future event (e.g. a manned mission to Mars), assume that it is actual as of 2050, and assume some tenseless truth about it. Given what exists now, of course, that truth could possibly fail to be true. But given what exists as of some other time, say, the year 2100, it is highly plausible that given what exists as of that time, the assumed truth about the hypothetical mission to Mars could not possibly fail to be true. So my solution is not in violation of ET-TSB.Footnote ²¹

What about the coherence of ET-TSB? The thought is that truth simpliciter can supervene on temporally dynamic being, and that it can do so in virtue of there being a correspondence between all the tenseless, contingent truths, on the one hand, and the totality of every event that exists as of some time t or other, on the other hand.Footnote ²² On this non-perceptual model, we conceive of God's eternal knowledge as that aspect of his mental life which includes the abstract objects of his purely conceptual knowledge (i.e. propositions, sets, numbers, etc.). Among these are all propositions about every possible event and human action, and among these are all of the true ones which correspond to the actual, temporal world. But that world is not eternal. It is dynamic in the sense that future events come into existence as time continues, and then remain in existence thereafter.

So there is a link between the eternal realm of God's abstract knowledge, on the one hand, and the concrete temporal world of events, on the other, and this link obtains at the ‘leading edge’ (so to speak – the language here is metaphorical) of temporal existence. On this model, every tenselessly true proposition has a corresponding event, but the correspondence depends upon the relevant event's having come into existence at some time t. If we abstract from any particular time, and consider the totality of contingent existence that is composed of every event that exists as of some time t or other, then we can see how this correspondence relation is possible. It is possible, because the totality of existence as of some time t or other gives us the concept of existence simpliciter (and thus can ground truth simpliciter, i.e. tenseless truth) but is also intimately linked with the concept of existence at a time (thus allowing that future events come into existence as time passes).

Let's unpack these last two claims. In order to do so, it is important first to understand the concept of a totality of contingent existence, since that is the concept that yields existence simpliciter, thus linking truth simpliciter with existence as of a time (i.e. the two constituent concepts of ET-TSB). First, we will consider the concept independently of truth simpliciter. Imagine, for example, a timeline with times t1–t5, and consider time t4. The totality of existence as of t4 is a mereological whole having as proper parts that which exists as of t1, that which exists as of t2, and that which exists as of t3. Thus, the totality of contingent existence as of any time t is composed of the sums of existence as of all times earlier than t. But that elucidation of the concept will not help us to make sense of truth simpliciter (and truth simpliciter is what we require for ET-TSB to be coherent), since propositions that are true simpliciter are true irrespective of a particular time, such as t4. This is why, in the preceding paragraph, I did not quantify over a particular time in characterizing the totality that is the supervenience base of truth simpliciter, but instead quantified over the totality of existence as of ‘some time t or other’. It is this general, disjunctive characterization of the totality of contingent existence which gives us the concept of existence simpliciter (and therefore truth simpliciter). That is to say, existence simpliciter is identical with the sum total of existence as of some time t or other. This is not to claim that existence simpliciter is, itself, time indexed. That, indeed, would be incoherent. It is, rather, to claim that on a view of time according to which events come into existence as time passes, anything that exists as of a particular time t will be a part of existence simpliciter, and, further, that the mereological whole of all that exists as of some time t or other just is existence simpliciter. And once we have the concept of existence simpliciter, it is a straightforward move to the supervening concept of truth simpliciter. Thus we are able to link the concept of existence as of a time with the concept of truth simpliciter, and to do so without threatening incoherence. On this view, every event that has come into existence in time is a proper part of existence simpliciter, but existence simpliciter is not, itself, temporally indexed.Footnote ²³

To sum up, the coherence of ET-TSB requires a mechanism whereby truth simpliciter can plausibly be said to supervene on existence as of some time t or other. Given the conventional view that truth simpliciter very plausibly supervenes on existence simpliciter (as in E-TSB, above), the mechanism for the job consists in the metaphysical relationship between existence simpliciter and the totality of contingent existence as of some time t or other. On a view of time according to which events come into existence in the present and then remain in existence, the totality of contingent existence as of some time t or other just is existence simpliciter. So truth simpliciter supervenes on existence simpliciter, which in turn is identical to the totality of contingent existence as of some time t or other, thus truth simpliciter supervenes on existence as of some time t or other. And, finally, given the coherence of ET-TSB, and the fact that the totality of contingent existence as of some time t or other has as a part the totality of existence as of any particular time t, we are able to affirm that there are tenseless truths about particular events that have not yet come into existence.

Now let's consider a concrete example of how all this metaphysical machinery is supposed to help with the foreknowledge and freedom dilemma. Take the proposition expressed by

(where t2 is the present), and assume that it is true. It is not correct to say that the proposition expressed by (11) is true now, nor at any time, nor even true to say that it is true at all times; it is tenselessly true, and God knows it as such. Nevertheless, it corresponds to Susan's going to Anstruther at t3; that is, the coming into existence of an event that does not yet exist (call this event E). This is possible because all of the eternal, contingent propositions about events in time correspond to, and supervene upon, the totality of what exists as of some time t or other. So although E does not exist presently as of t2, the totality of contingent existence as of some time t or other, upon which the truth of (11) supervenes, includes as proper parts both that which exists as of t2, and that which exists as of t3; and it is this eternal-temporal supervenience that explains how God can know (11) without that knowledge fixing E. Instead, E is fixed in virtue of its occurrence at t3, and it is Susan's free action at t3 that is (at least partially) responsible for that occurrence.

I hope it is clear that this working out of ET-TSB does not fall foul of Zagzebski's Timeless Knowledge Dilemma (TKD). I argued above that the TKD would only be a concern for the traditional Boethian solution if we attempted to marry that solution with a metaphysics of time according to which the future does not exist, since, on that metaphysics, it is implausible that God's knowledge of non-existent future – from our perspective – events could be grounded in such events. In the case of the modified Boethian solution presented here, however, God's knowledge of events that are yet future is not based on his observation of those events from a non-temporal perspective; rather, his knowledge is based on the supervenience relation that obtains between eternally existing, tenseless propositions, on the one hand, and events that come into existence as time passes, on the other. So the TKD is not a dilemma for ET-TSB and the modified Boethian solution.

Another objection to my working out of ET-TSB might be to claim that if the totality of contingent existence as of some time t or other has parts that are the supervenience bases for truth simpliciter, then surely those parts must exist simpliciter; in which case, those parts do not exist as of a time (in spite of my claims above). This, however, would be to misconstrue the supervenience base: it is not the parts of the totality of existence as of some time t or other that truth simpliciter supervenes upon, but the mereological whole itself (i.e. existence simpliciter), and this totality, by definition, does not exist as of a particular time. It is true that that totality is composed of parts that exist as of particular times, but, again, these parts are not the supervenience bases of truth simpliciter.

Thus, it is crucial to my account that we do not view the relationship between truth and ontology on the model of either E-TSB or T-TSB. One must free oneself from the prejudice of these two versions of TSB, and not demand that tenseless truth require tenseless existence, nor that tensed existence require tensed truth, but allow that tenseless truth can supervene upon that which comes into existence. Why, after all, must truth be isomorphic with existence in order for the former to supervene upon the latter? On the present view, truth is abstract and eternal, while contingent existence is concrete and dynamic, so although the one supervenes upon the other, the two are of a very different character. So the violation here is not against coherence, but merely convention; and as the arguments above show, there is a systematic way to be both coherent and unconventional in this regard.

Thus, ET-TSB provides a satisfactory answer to the TSB problem associated with the modified Boethian solution. Next we will consider the problem of ontological commitment. As I stated above, the ontological commitment problem challenges me to explain how I can allow for quantification over future events, while not admitting them into my ontology.

In response, first let me state that nothing I say, think, or believe commits me to the existence of future events. When I quantify over future events, the mode of certainty is radically different from that in other controversial cases of ontological commitment; such as those involving sets, numbers, propositions, possibilities, and even fictional entities. These all involve quantification over, and commitment to, certain types of entities; and that is where the controversy lies – whether those types of entities actually exist, and whether quantification over them can be avoided. The controversy does not lie in uncertainty about the token judgements falling under one of these types. Thus, in the case of numbers, we all believe that 7 + 5=12, but the controversy is whether that belief commits us to the existence of numbers. In the case of future events, however, the token judgements cannot be known by us with any degree of certainty, so the question of ontological commitment is not nearly as pressing for us (i.e. for human beings). Suppose, for example, that the following is true:

My solution requires that (12) express an eternally existing, tenselessly true proposition, even though there is not now anything in reality that corresponds to it. Does this statement of my solution violate Quine's dictum, ‘to be, is to be the value of a bound variable’? Why should it? For all I know, (12) is completely false. I have had to assume its truth just to simulate what is known from God's perspective, and so to represent the objects of his knowledge. But this process of assuming, simulating, and representing as if falls far short of asserting or believing the truth of (12). And it strikes me that I only incur an ontological commitment if I assert or believe some existential proposition.

So, in stating my solution to the problem of divine foreknowledge and human freedom, I certainly do not quantify over future events in any way that would commit me to their existence. On this view, when we, as human beings, posit truth about the future, we are positing a purely semantic thesis. We have no access to singular terms for non-existent future individuals and entities. Only God has access to these, and so only God's thoughts, beliefs, assertions, about future events commit him to their existence. Well then, what should we say about God's ontological commitment to future events? The answer to that question was provided in the previous discussion regarding TSB. God's beliefs about future events do commit him to their existence, but his beliefs are eternal, and the events which they are about come into existence contingently. So he is not committed to the existence of future events now, he is eternally committed to their coming into existence as of the times they do.