Rea has argued in “Presentism and Fatalism” that presentism + bivalence + libertarian free will form an inconsistent triad. (The paper can be found here.)

I’m trying to *understand* his argument. I’ll explain what I take to be the basic strategy behind the argument and why I don’t see how that strategy can succeed. I’ll then offer a hypothesis as to why Rea might have mistakenly thought his argument succeeds. All of this is designed to help you, the audience, understand the nature of my lack of understanding of Rea’s argument. The hope is that someone will straighten me out. (I hope this note isn’t too far removed from philosophy of religion… Rea’s argument does have implications for theological systems: e.g., a presentist might view it as a challenge to the free will defense.)

**The Argument**

Suppose for reductio that (i) Sally freely stands up, (ii) presentism is true, and (iii) bivalence is true.

Let P be the proposition that Sally stands up.

Given (i), it seems that Sally has (had or will have) a choice about the truth of P.

Rea’s argument is supposed to reveal that Sally does not have (never had and will never have) a choice about the truth of P if (ii) and (iii) are true. As I understand his argument, his overall strategy is to identify a proposition Q, such that if (i) and (ii) are true, then

(A) There was a time when Sally didn’t have a choice about the truth of Q,

And

(B) Q entails P.

Rea seems to think that (A) + (B) + plausible auxiliary premises entail that Sally does not have (never had and will never have) a choice about the truth of P.

For the sake of argument, I will grant that if there is a Q that satisfies (A) and (B), then Sally never freely stands up. What I do not see is what Q might be.

After reading Rea’s argument, I thought that perhaps Q is what Rea calls, ‘M2’, which I take to be the proposition that the proposition that Sally will stand in exactly 1,000 years hence was true at a time that obtained exactly 1,000 years ago.

M2 does seem to entail P. So, condition (B) is met. What about (A)? Was there a time when Sally didn’t have a choice about the truth of M2? Not obviously. Notice that M2 is true when and *only when* P is true: when P is false, it is not the case that 1,000 years ago it was true that in 1,000 years Sally will stand. So there are no times in the distant past, say, when M2 was true but Sally was not around to ground it’s true. M2 is only true when Sally is around and indeed is standing. Thus, I see no reason (in anything Rea says) to think that when Sally chooses the truth of P she doesn’t also choose the truth of M2.

But if M2 doesn’t play the role of Q, what does? I’m at a loss.

**Diagnosing the Problem**

I have a conjecture as to where Rea’s argument might go wrong. I begin by noticing that instead of P, Rea considers P*, the proposition that Sally stands *now*, where I’ll assume that P* is equivalent to the proposition that the present time, t, includes (entails) P. Now let M2* = the proposition that there is a time 1,000 years earlier than t which includes the proposition that P will be true in 1,000 years (maybe this is what Rea actually meant by M2). Interestingly, M2* satisfies conditions (A) and (B), with respect to P*: M2* entails P*, and since M2* was always true (including times before Sally was born), there were times when Sally didn’t have a choice about the truth of M2*. The conclusion, then, is that Sally does not have (never had and never will) a choice about the truth of P*. My conjecture is that *that* conclusion was in Rae’s mind when he concluded that Sally has no choice about the truth of P.

Confusing P* with P would be natural to do from an eternalist perspective, given that truths are typically time-indexed on eternalism (to avoid contradictions: e.g. there are dinosaurs and there are no dinosaurs are both true, but at different times). But if P is not a time-indexed proposition, then P and P* are *very* different. P* is a necessary truth: it is necessary that P is included in that maximal state of affairs, called t (recall, Rea is supposing the presentist framework according to which times are abstract, maximal states of affairs). By contrast, P is contingent. P was false before Sally was born, for example. P*, on the other hand, was true long before Sally was born. So, just because Sally doesn’t have a choice about the truth of P*, it does not follow that Sally doesn’t have a choice about the truth of P.

Well, that’s just a *conjecture* about where the argument goes wrong. To be honest, I don’t understand Rea’s argument: I don’t know what he means by various expressions in his premises (such that the premises are plausible and the argument valid). What I do understand is that even if presentism and bivalence are true, neither M2 nor M2*, nor any other proposition I know of, satisfies (A) and (B) with respect to the proposition that Sally stands. Thus, it’s presently not clear to me why combining presentism with bivalence should pose a problem for libertarian free will.

What am I missing?

Josh,

Here’s the gist of Rea’s argument, as I understand it. Assume presentism and TSB (truth supervenes on being). It follows that all truths (or at least all contingent truths) supervene on present reality. Now consider propositions about future contingents. What present reality could their truth supervene upon? Given presentism it appears that nothing is available as a supervenience base. One can’t ground their truth in future events because, given presentism, those events don’t exist. Nor can one ground them in present reality because, in so far as they concern future contingents, the present is indeterministic with respect to which outcome occurs. Rea concludes that presentists who accept future contingents must deny that any propositions about them are true. That he takes to imply a denial of bivalence.

That last part about implying a denial of bivalence is incorrect (as I argued in my 2006 F&P paper), but Rea’s point can be generalized. Say that the future is “alethically open” just in case there is no unique and complete true story of the future (i.e., one that correctly represents a unique sequence of events as “the” actual future). Otherwise, say that the future is alethically settled. In these terms, Rea’s argument is that the following four propositions form an inconsistent set:

1. Truth supervenes on being (TSB).

2. There are future contingents.

3. Presentism is correct.

4. The future is alethically settled.

In my view, this set is inconsistent. Hence, at least one them must be given up. In response, theological determinists reject 2. Most open theists reject 4. And most non-open free will theists (Molinists, etc.) deny either 1 or 3. Thus, Rea rejects 3 and Merricks rejects 1. Some, like Bills Craig and Hasker, ostensibly affirm all of 1-4, but I think they wind up paying lip service to TSB while implicitly denying it in favor of a deflationary account of truth, rather like Merricks.

Andrew,

If your interpretations are correct, then as you note, M2 doesn’t entail P. If P* is equivalent to P, then M2 doesn’t entail P*, either. But Rea thinks it is *trivial* that M2 entails P* (M7). This leads me to suspect your interpretations are not what Rea intends.

Presentism you say?

Maybe one should take a step back and focus on “Has Einstein proven presentism to be false?” There is quite large agreement among physicists and mathematicians that he did. Just like they agree that Leibniz and Newton solved the paradox that Zeno offered to disprove motion by giving us calculus.

So, isn’t discussing what presentism implies a rather fruitless exercise? Once you have seen the top of mount Olympus, it seems quite reasonable not to ask “When will be the next time Zeus turns into an animal to have a child with some innocent girl?” anymore.

Hi Pumbelo,

Most presentists have, as you put it, taken a step back and asked that question. There’s a lot of literature on this. There’re a number of articles in the book that Craig and Smith edited:

http://www.amazon.com/Relativity-Simultaneity-Routledge-Contemporary-Philosophy/dp/0415701740/ref=sr_1_1?ie=UTF8&s=books&qid=1245445671&sr=1-1

and Craig wrote a whole book on it:

http://www.amazon.com/Time-Metaphysics-Relativity-Philosophical-Studies/dp/0792366689/ref=sr_1_18?ie=UTF8&s=books&qid=1245445809&sr=1-18

There’s other philosophical literature out there on it as well. (To be honest, though, I don’t understand most of it. I just know that a lot of smart presentists have responded.)

There’s a lot of literature on that.

Hey Josh,

I think his M7 is ambiguous. So he writes,

M7) M2 entails Sally stands now (at t, one thousand years later than t).

This is ambiguous because it is unclear whether it is stating that M2 entails âSally stands nowâ or that M2 entails âSally stands at tâ. I think he should take the latter route.

However, now that I think about it, I’m not sure if that is trivial or not.

Anyway, I discuss this in footnote 7 of my paper. Also, the reason I asked if you got my paper was because my Yahoomail account is malfunctioning, and so I can’t see what I’ve sent.

Is what you question about my interpretation whether ‘t’ and ‘t*’ are used as proper names?

whoops, I repeated “there’s a lot of literature on it” three times in my response to Pumbelo. that was unintentional, and I wrote my comment fast.

Alan,

Thanks for that suggestion. I want to see if I can see how your 1-4 are inconsistent. You suggest that given presentism, a proposition about a future contingent cannot be grounded in present reality because the present is indeterministic with respect to which outcome occurs. So the idea, I take it, is that the following are incompatible:

1. The proposition P that x will happen is grounded in E.

2. E is indeterministic with respect to x’s happening.

I take (2) to say

2a. E does not entail that is true.

And not

2b. E does not entail that will be true.

But if 2 = 2a, then (1) and (2) are compatible. (Or at least, it’s not clear why they wouldn’t be.)

On the other hand if 2=2b, then (1) and (2) are not compatible. But why should someone who believes in future contingents (or in lib. free will) accept 2b?

This is all very interesting to me because I think I accept 1-4.

Pumbelo,

I’m familiar with Einstein’s paper and many of the subsequent experiments to support his STR and GTR. I wasn’t convinced by Einstein’s arguments, however, and the subsequent experiments are compatible with presentism. My wife is a scientist, and it’s become very evident to both she and I that the scientists often are unaware of the philosophical assumptions they make in their arguments. For a presentist metaphysical account consistent with the scientific data, see data http://www.twow.net/MclOtkCaLbStr.htm. (Part of the story wrt STR is to suppose that causal interactions slow down as collections of particles increase in velocity due to the greater distance “energy” must traverse to move from one member of the collection to the other…)

Andrew, you may be correct that he views ‘t’ and ‘t*’ as proper names. In that case, his M2 is what I called, ‘M2*’ (I think). But M* doesn’t entail P…

Alan,

Oops, I meant:

2a. The existence of E does not entail that [x happens] is true.

2a. The existence of E does not entail that [x happens] will be true.

*Here’s the gist of Rea’s argument, as I understand it. Assume presentism and TSB (truth supervenes on being). It follows that all truths (or at least all contingent truths) supervene on present reality.*

Does that include contingent truths about what occurred in the past?

1. There is a mistake in the original paper. M8 should read “Therefore, Sally has never had and never will have a choice about Ps.” Ps is the proposition that [Sally stands in 1000 years].

2. Mike explicitly formulates Ps so as not to be vulnerable to the following sort of worry: Ps is that [Sally stands at t]. But if Ps is true, then it’s necessarily true , since for a proposition to be true at a time is just for the time to include the proposition. But then of course Sally has a choice about whether t obtains. That is why Ps is [Sally stands 1000 years hence], and Mike doesn’t want it to be analyzed as [Now it’s t*, Sally stands at t, and t is 1000 years later than t*].

3. Pumbelo, most presentists have what they consider to be satisfactory responses to the argument from SR. I point you to Tom Crisp, Dean Zimmerman, Bill Craig, Ned Markosian, and Mark Hinchliff.

4. Tim, yes, it does. Things in the past don’t have being. So presentists who accept some kind of TSB or truthmaker want to pack the supervenience base into the present. Tom Crisp does this in his 2008 Nous paper “Presentism and the Grounding Objection” by using abstract times, and he’s got a new idea coming out. Alan Rhoda has argued in a recent PPQ paper that they’re in God’s mind.

*So presentists who accept some kind of TSB or truthmaker want to pack the supervenience base into the present. Tom Crisp does this in his 2008 Nous paper “Presentism and the Grounding Objection” by using abstract times, and he’s got a new idea coming out. Alan Rhoda has argued in a recent PPQ paper that they’re in God’s mind.*

OK, thanks. I’ll look into the Nous paper myself, but can you briefly explain how using abstract times would work?

I can see how, if you have a perfect deity, his present memories could serve as the truthmaker for statements about the past, and thus you avoid the unpalatable result that e.g., it used to be true that *Cain killed Abel in 3990 BC* but now it’s neither true nor false. But it still seems pretty implausible to me. It’s *that the event occurred as the statement says it did* that makes the statement true, not the present effects of that past event, e.g., it’s Cain’s killing of Abel in 3990 BC that makes the previous statement true, not the traces of that event in God’s memory.

Tim,

There’re a number ways that presentists have dealt with the grounding objection. Here’s a sentence from a paper I wrote w/some bibliography, “Presentists have not been short of giving answers to this question: perhaps it was some presently existing contingent property of a segment of space [Lucretius 1994; Bigelow 1996: 44-6], a contingent property of the whole world [Bigelow 1996: 46-8], Sallyâs haecceity [Keller 2004], a time in an ersatz B-series of abstract times [Crisp 2006], a brute future [Kierland and Monton 2007], or perhaps nothing substantive at all [Merricks 2007].”

Lucretius Carus, Titus 1994. On the Nature of the Universe, translated by R. E. Latham, revised with an introduction and notes by John Godwin, London, New York, Victoria, Toronto, Auckland: Penguin Books.

Bigelow, John 1996. Presentism and Properties, Philosophical Perspectives 10: 35-52.

Keller, Simon 2004. Presentism and Truthmaking, in Oxford Studies of Metaphysics, 1, ed. Dean W. Zimmerman, Oxford: Oxford University Press: 83-104.

Crisp, Thomas 2006. Presentism and Grounding, Nous 41: 90-109.

Kierland and Monton (2007). Presentism and the Objection from Being Supervenience, Australasian Journal of Philosophy: 85: 485 â 497

*Josh: The idea, I take it, is that the following are incompatible:
1. The proposition P that x will happen is grounded in E.
2. E is indeterministic with respect to x’s happening.*

I would put things slightly differently. Where x is a future contingent event, it is now causally possible that x happen and causally possible that x not happen. Given presentism and TSB, all contingent truths are grounded in present reality. Let E be the totality of present reality. Then the proposition that x will happen, if true, is grounded in E. But given the future contingency of x, it doesn’t seem that the truth of [x will happen] could be grounded in E for, by hypothesis, E is indeterministic with respect to whether x happens and so does not suffice to make [x will happen] true. In other words, that E obtains is consistent with both [x will happen] and [x will not happen].

To avoid this result, the presentist has to either reject TSB or pack enough into E so that [E obtains] does entail [x will happen]. But then it’s not at all clear how x can still be a future contingent.

*Josh: I take (2) to say*

2a. That [E obtains] does not entail that [x happens] is true.

And not

2b. That [E obtains] does not entail that [x happens] will be true.

2a. That [E obtains] does not entail that [x happens] is true.

And not

2b. That [E obtains] does not entail that [x happens] will be true.

Strictly speaking, it’s not E (present reality) that does any entailing, but the proposition that E obtains. Hence, I’ve amended your 2a and 2b accordingly. That aside, I think you’re mistaken to read (2) as 2a and not 2b. After all, we’re supposed to be talking about a

*future*contingent, whereas 2a only talks about the present.

Suppose x is a recurring event (like a sea battle). And suppose that just such an event is occurring right now. Well then, that E obtains does entail that [x happens] is true. But a present occurrence of x isn’t a future contingent. So 2a is irrelevant. We need 2b to talk about

*future*contingent sea battles and, as explained above, it’s not at all clear how E could ground the present truth of [x will happen] or the future truth of [x happens] given that x is a future contingent.

*Josh: But why should someone who believes in future contingents (or in lib. free will) accept 2b?*

It’s precisely because one believes in future contingents that one should accept 2b. The only out that I can see, apart from denying presentism or TSB, is to pack enough into E such that [E obtains] entails for some future contingent x that [x will happen]. But one can’t do this by positing tendencies or causes sufficient to bring about x, for either those will be too weak for [E obtains] to entail [x will happen] or they will render x a deterministic consequence of E, and so not a future contingent. What Bill Craig and others ultimately do to get around this problem is to posit

*brute*presenting existing future-tensed facts like x’s going to happen (at such-and-such a time). That, however, strikes me as a paradigm case of metaphysical cheating because such facts are explanatorily vacuous–they make no specifiable difference to E other than the mere obtaining of the alleged future-tensed fact itself. (What is the world like such that x will obtain? Answer: It just is the case that x will obtain.) So why should anyone who is not already sold on 1-4 take such facts seriously?

Here’s a thought about Rea’s article (I’ve had a correspondence with him about it, but I don’t remember all the details now, and so I should note that he had good responses to make to me). Take Rea’s argument. Replace every occurrence of the future tense by an occurrence of the past tense, and vice versa. Move every future event to the past, and vice versa. What is interesting is that all the premises of the argument remain equally plausible as they were, because all the controversial premises are neutral with regard to tense. And we now have an argument for the conclusion that the presentism + past-bivalence + libertarian free will are an inconsistent triad, where past-bivalence is bivalence about past-tensed propositions.

Let me be a little more explicit about the transformed argument. I am exactly paralleling the argument on pages 11 and 12 of the online PDF. Suppose that t* is a thousand years AFTER Sally’s standing up. For simplicity, assume that Sally doesn’t exist at t* (if one thinks it’s a necessary truth that agents exist forever, the argument will need some tweaks).

M1) Presentism is true. (Assumption)

M2*) PS will be true at t*. (Assumption.)

M3*) If presentism is true and if PS will be true at t*, then the truth of PS at t* will not be even partly grounded in the occurrence of any event involving Sally or in any exercising of her agent-causal power. (Premise)

M4*) Therefore: The truth of PS at t* will not be even partly grounded in the occurrence of any event involving Sally, or in any exercising of her agent-causal power. (From M1, M2*, M3*)

M5*) If the truth of a proposition p at a future time tn will not be even partly grounded in the occurrence of any event involving S, or in the agent causal activity of S, then S has never had and will never have a choice about whether p will be true at tn. (Premise)

M6) Therefore: Sally has never had and will never have a choice about whether M2 is true. (From M2*, M4*, M5*)

M7*) M2* entails that Sally stands now (at t, one thousand years earlier than t*). (Trivial)

beta3) If p and if x never had and never will have a choice about p, and if p entails q, then x never had and never will have a choice about q. (Premise)

M8) Therefore: Sally has never had and will never have a choice about PS (corrected from P2). (From M2*, M6, M7*, beta3.)

I asterisked those premises where I had to make a change. Interestingly, beta3 did not require any changes. M2* is simply stipulated as a consequence of past-bivalence, just as M2 was stipulated as a consequence of future-bivalence. M7* is trivial in the same way that M7 was. Therefore, the only significant changes in my argument were to change M3 to M3* and M5 to M5*. Moreover, Rae’s support for M5 on pp. 12-13 is independent of the tense in M5 (while M5 talks of a “past” time tn, the considerations adduced for M5 do not make any use of the assumption that tn is past), and hence establishes M5* just much as it establishes M5. Furthermore, Rae’s argument for M3 is independent of the tense, and hence establishes M3* just as much.

Therefore, anybody who found Rae’s argument as a whole (including the support he gives for M3 and M5) persuasive, should find my modified version persuasive as well.

But here is something that on most people’s metaphysics–though not mine!–will count as a counterexample to M5*. Suppose that today Sally starts a forest fire. As a result, two years from now, at a location x where there now is old growth, there are a bunch of saplings. Let p be the proposition that there are saplings at x. Let tn be two years in the future. Then, p is true at tn. In two years, it seems that the truth of p will be grounded solely in the saplings’ presence at x. It surely seems like p will not be grounded in the occurrence of any event involving Sally, or her causal activity. Of course, the saplings’ presence is remotely *caused* by Sally’s activity, but a remote cause of an event, even if essentiality of origins is true, on the most common metaphysical views is not a part of the *grounding* of the proposition reporting the event. (I actually am inclined to deny this metaphysical thesis, on the basis of controversial Thomistic metaphysics–see the Thomistic argument for the CP in my PSR book.)

So, on the most common metaphysical views, the antecedent of M5* is in fact satisfied in the forest fire and saplings case, whether presentism or eternalism is true. Hence, if M5* is true, its consequent is true, and Sally never had and will never have a choice about whether there are saplings at x, and this conclusion follows independently of one’s view of time. But of course she does have a choice about it! So, the consequent is false, the antecedent is true on the most common metaphysical views, and hence on those views, M5* is false.

If so, then only someone who holds to a very controversial thesis that even a remote cause of an event is a part of the truth-grounding of the proposition reporting the event can affirm M5*. But the argument for M5 also implied M5*. Hence, unless one accepts this controversial thesis, one should reject Rae’s argument for M5. Therefore, the presentist should reject M5 as not soundly supported, unless the presentist accepts the controversial metaphysics.

Now, there is a way of fixing up Rae’s argument, which he may have intended. Stipulate that instead of “p is grounded in E” meaning something like “E is a truth-ground for p”, it means “E is explanatorily prior to the truth of p” (Rae says something somewhat along these lines at the bottom of p. 12). Then, in that stipulative sense of “grounded”, Sally’s starting the forest fire really does ground the presence of saplings at x two years later. With this stipulation, M5* is immune to my counterexample, and pretty plausible.

However, now M3* becomes implausible at least to the TSB presentist (while M5* is probably going to be implausible to the non-TSB presentist). Why? Because now M3* says: “If presentism is true and if PS will be true at t*, then the truth of PS at t* will not be even partly explained by the occurrence of any event involving Sally or in any exercising of her agent-causal power.” But why not? Consider the case of the saplings. At t* we have saplings, let us say. Their existence is partly explained by Sally’s having started a forest fire two years earlier, an “event” (or at least state of affairs–but that should be good enough) existing at t*, and one that in some sense involves Sally, even though Sally no longer exists. And if one understands “involves” in such a way that an event cannot “involve” a pastly existing person, then the presentist will have good reason to deny M5* as question-begging.

Now, if we deny M3* we have to say that the argument is unsound. But the argument for M3 was the same as the argument for M3*. Hence, the TSB presentist has good reason to say that the argument for M3 is unsound, since it leads to the false conclusion M3*.

There is, however, an intuitive sense in which M3 is more plausible than M3*. One might find it more plausible that an earlier event could be explanatorily prior to a later event than that a later event could be explanatorily prior to an earlier one. If so, then one might accept M3 while rejecting M3*. But I think that this difference is based on a no-backwards-causation intuition which Rae, if memory serves, says is not behind his argument. Besides, this is only plausible for causal priority, while for acausal priority, M3* seems on par with M3.

Alex-

That’s really interesting. In a response to Mike, I also made a parallel argument, replacing the distance measure between times (years) with a distance measure on worlds (“zears”), and ended up with an argument that the conjunction of libertarianism+bivalence+actualism is inconsistent. I think it’s slightly less compelling initially than your parallel argument, but it’s hard to see where it goes wrong. But, certainly it does! So, then, I think Mike’s does too, though I can’t say exactly why.

Tim-

I’ll let Alan explain his position. Andrew briefly outlined Tom’s. In a bit more detail, the idea is that times, like worlds, are maximal propositions. So, each time includes all the true propositions about the present, past and future. The times are related by B-relations. Tom says the relations hold contingently, and I think what he means is that it’s contingent that any of them become actual/true. Then the truth of past propositions are grounded in that they’re included in the conjunction of the abstract time that is presently true.

The many suggestions here (and papers e-mailed to me) have been quite helpful to me. Thank you, all.

Hi Josh,

Did you get my paper?

There are some parts of what you wrote that I was unclear on. You take ‘M2’ to denote the proposition that the proposition that Sally will stand in exactly 1,000 years hence was true at a time that obtained exactly 1,000 years ago.

But M2 is, to quote Rea, the proposition that “Ps was true at t*”, where Ps is the tensed proposition

that Sally will stand exactly one thousand years hence, and I believe that he uses ‘t*’ as a proper name to designate a specific time one thousand years ago. So I don’t think your M2 is equivalent to Rea’s M2. For example, while your M2 entails P, Rea’s M2 does not entail P.Secondly, I think that your P and P* are equivalent. So I think that the proposition

that Sally stands upand the propositionthat Sally stands up noware equivalent. This is because I think that P* is also not a time-indexed proposition. The addition of “now” is just the addition of anindexical, and so it will refer to whatever time happens to obtain at that time.Unfortunately, there’re a lot of nitpicky things that need to get cleared up before discussion moves on. I think that a coherent way of understanding Rea’s argument is found in my paper. Let me know what you think of that.