Saturday, June 16, 2012

Changing Truthmakers

I've posted a new paper, 'Changing Truthmakers'.  It's a reply to a paper by Jonathan Tallant and David Ingram, which is in turn a reply to my 'Truthmaking for Presentists'.

It's about how we can stop truthmakers for tensed truths changing, so as to ensure the validity of theorems of tense logic like 'If it's now the case that p, it always will be the case that it was the case that p'.  And I get to talk a bit about hypertime, which is always cool!

Sunday, June 10, 2012

The Time-Travelling Trinitarian God

After having too much caffeine I started thinking about the metaphysics of the Trinity, for no immediately obvious reason.  The following is crazy, but maybe kinda fun too?  Well, here goes nothing . . .

It’s time t0: the very first instant there is.  At this instant, there exists God the Father and God the Son.  One event occurs at this instant: God the Son is begotten of God the Father.

What is the relationship between God the Father and God the Son?  Well, we already have part of the story: the latter is begotten of the former.  Is there anything else we can say at this point?  One might be tempted to conclude that we know also that they are numerically distinct, since nothing is begotten of itself.

Certainly, this claim of distinctness seems to fit well with some of the things God the Son goes on to say.  He says, after all, that God the Father is greater than he is: and surely nothing is greater than itself!  Other things he says seem to at least conversationally imply that he is distinct from God the Father, even if they don’t logically entail it.  He says, for example, that no-one can come to the Father except through him (the Son): it would be less misleading to simply say ‘No-one can come to me except through me’ if that’s what this amounted to, as it surely would were the Father and the Son the same being.  All in all then, it seems like there is good reason to conclude that we have two things here: the Father and the Son.

Unfortunately, the Son also says some things that suggest that he is not distinct from the Father.  He says that he and the Father are one.  He doesn’t elaborate too much on what he means (he has a fondness for the cryptic!), but the smart money is on the claim that he’s saying they are of one essence.  And we have good metaphysical reasons for thinking that if A and B are of one essence, they are numerically identical.  For surely it is part of the essence of A that it is A and not some other thing.  And if B is not A then it is certainly not part of B’s essence that it is A.  So if A and B are distinct then they are not of one essence.  We also have theological reasons for thinking that the Father and the Son are identical, for we believe each of (i) The Father is divine, (ii) The Son is divine, (iii) For all x, if x is divine then x is a god, and (iv) There is exactly one god.  And (i)-(iv) together entail that the Father is the Son.

So we’re in a quandary: the story so far pulls in two directions, some things indicating that the Father and the Son are distinct, some things indicating that they are identical.  Let us now see how the story progresses.

God the Father is really powerful.  In fact, he can do anything metaphysically possible.  This is true at time t0, and it remains true for ever.  He never loses any of his powers; and of course he never gains any, since he can already do anything possible (and that’s as powerful as it’s possible to be).  God the Son, on the other hand, starts off life at t0 far less powerful.  (Hence his claim that the Father is greater than he is.)  But unlike the Father, the Son grows in power over time until, at the very last moment of time, tz, he is himself capable of doing anything metaphysically possible.  One of the things he can do at tz is travel in time, this being metaphysically possible.  And so he does: he travels back to t0, at which point he calls himself God the Father and begets the earlier less powerful version of himself, calling him God the Son.

This is the story of a time-travelling deity.  At the beginning of time there is only God: but there are two ‘versions’ of him – there is the all powerful being he becomes at the end of time, who travelled back in time to the first moment, and there is the less powerful being that he started out as, who was begat by his more powerful future self after he travelled back in time.

I am not claiming that this is how the world is.  But I think it is possible, and that if it is true then the data we started with is accounted for.  Thus, I think we have here a metaphysical model that vindicates the orthodox Christian understanding of the relationship between God the Father and God the Son.

Consider the first puzzle: how can the Son be the Father if the former was begotten of the latter?  Well, if time travel is possible, cases of self-creation just aren’t that puzzling.  Let’s suppose that a man undergoing a sex change would be capable of giving birth.  So suppose I now, in 2012, travel back in time to 1979, wait a year and get a sex change and then travel back in time to 1979 again; at that point my male self that came back from 2012 can mate with my female self who came back in time from 1980, who will then give birth to infant me in 1980, who will grow up to back in time in 2012.  This scenario is perfectly consistent, and it involves me creating myself.  So there’s nothing impossible about God going back in time and begetting his earlier self.

It’s also clear that if this is how things are, God the Son’s declaration that the Father is greater than he is is a perfectly sensible thing to say.  If I go back in time to 1980 then I can look at infant Ross and truly say ‘He is me’, but I can also sensibly say ‘I am taller than he is’.  In general, if something that changes across time travels back in time to a time when it was different, then we can sensibly contrast how its later self is with how its earlier self is, even though they are the same thing.  Thus the Father, God’s later self, can sensibly be said to be greater than the Son, his earlier self, despite them being the same being.

Similarly, if I go back in time to protect my infant self in the cradle, I can sensibly say ‘Nobody gets to him except through me’.  And it’s simply not more conversationally informative for me to say ‘Nobody gets to him except through him’, despite the fact that I am he.  Since I can sensibly contrast my later self with my earlier self – my later self is bigger and stronger – then I can sensibly say that it is my later self protecting my earlier self and not my earlier self protecting my earlier self, despite the fact that my later self is my earlier self.  Likewise, if it requires a being like us in some respects to bring us to a being who is so far beyond us in power, then the Son can sensibly say that it is only he that can bring you to God the Father; and it would not be better for him to say that it is only the Father that can bring you the Father, despite the fact that he is the Father.

Note that I’m not claiming that these contrastive claims are true, only that they are sensible claims to make in those circumstances.  Whether or not they are true depends on some tricky issues concerning persistence and change.  It’s a prima facie puzzle if A is F and travels back in time to a moment when it is not F, for then it seems that at that time A is F and not F – contradiction!  What should we say about this puzzle?  It’s obviously similar to the familiar problem of temporary intrinsics – how can David be hairy at one time and not hairy at some other time (once he’s lost his hair), given that it’s one person here, and nothing differs from itself?  But in our case, it’s not another time: it’s the same time, because the A that is F has gone back to meet the A that is not F.

Here are some common responses to the problem of temporary intrinsics.  The perdurantist thinks that the thing that is hairy is not David, but rather a temporal part of David, and the thing that is not hairy is a different temporal part of David.  Since these temporal parts are numerically distinct, there is no puzzle in their being different in properties.  When David says in his early life that he is hairy, he speaks truly, because the truth-conditions of his utterance are that the temporal part that makes the utterance is hairy.  If this is the correct response to the problem of temporary intrinsics, it carries over straightforwardly to the time travel case.  The later version of A that travels back to meet its earlier self is really a different thing: it is a later temporal part, and it is meeting its earlier temporal part, and so there is no puzzle in one being F and the other not being so.  On this view, I speak truly when I travel back and say that I’m taller than my infant self: the temporal part that makes that utterance is taller than the temporal part that’s in the cradle.  Similarly, the Son speaks truly when he says that the Father is greater than he is: the Father is God’s later temporal part, and does indeed have more powers than the Son, who is God’s earlier temporal part.

But suppose perdurantism is false.  The two most common endurantist solutions to the problem of temporary intrinsics need modification if they are to handle the time travel case.  On one view, things are incapable of changing with respect to their monadic properties, and what we normally think of as a thing changing with respect to a monadic property is in fact it standing in a certain kind of relation to some times but not others: so while it looks like David is hairy simpliciter at one time and not at another, in fact David is never hairy or not hairy simpliciter but rather bears the being hairy relation to some time but fails to bear it to a later time.  But if we’re to allow for the time travel case we will have to say that apparent monadic properties are not two place relations between an enduring object and a time, but rather three place relations between an enduring object, a time, and a place.  So when A travels back to meet earlier A, it is true simpliciter that A bears being F to time t and place L1 and true simpliciter that it fails to bear that relation to time t and place L2.  (L1 being the place the future version ends up at t, L2 being the place the earlier version is at that time.)

What are the truth-conditions for ‘A is taller than B at time t’ if height properties are really three place relations between an object a time and a place?  There are various options: perhaps it’s true iff every height relation A bears to some place at t is greater than every height relation that B bears to some place at t; perhaps it’s true iff there’s a mapping that takes you from the height relations A bears to some place at t to the height relations B bears to some place at t (leaving no relations out) and which maps greater relations onto lesser ones; and there are other options.  But if either of those suggestions are correct, it would turn out to be false when I go back in time and say, looking at my infant self, that I am taller than he.  For if A=B then they will bear the same height relations to places at a given time, and so it’s hard to think of a sensible option on which it could come out true that A is taller than B at a time.

Another common endurantist option is to hold on to the thought that apparent monadic properties are just that, but to deny that such properties are ever had simpliciter: instantiation of such properties is always relative to a time.  So David has being hairy a certain way (i.e. relative to the earlier time) but he lacks that property some other way (relative to the later time).  The natural extension of such a view to allow for time-travel cases is to relativise instantiation to both time and place.  And it’s easy to see why, for similar reasons to those above, this is going to lead to a similar conclusion: that I won’t speak truly when I look at my infant self and say that I am taller than he.

So return to God the Son’s assertion that God the Father is greater than he is.  If God is a perduring object then there’s no problem in this being straight-forwardly true.  At t0 there are two distinct things: the earlier temporal part of the spacetime worm that is God and the later temporal part of God – the former lacks omnipotence, the latter has it, and the utterance the former makes is thereby true.  If God is an enduring object, however, it looks like the Son’s utterance is false: for everything we can say about the Son’s powers at t0 will also be things we can say about the Father’s powers at t0.

I don’t want to take a stand on the perdurantism versus endurantism debate here.  What I want to argue is that each option adequately accounts for the data.  The perdurantist option does so by rendering the Son’s utterances concerning his relationship to the Father straightforwardly true.  The endurantist option renders some of them false; but I think this shouldn’t worry us, because the Son’s claims are still sensible things to say in these circumstances, and this is all we should need to secure.

If I’m an enduring object and travel back to meet my infant self, then I am in 1980 twice over: I am bi-located at that time.  Suppose I’m trying to locate my infant self, who is in a hospital in Glasgow, but I don’t know how to get there from where my adult self is (Leeds, let us suppose).  You’re trying to help me get there and you ask ‘Are you in Glasgow?’.  I can truly answer ‘yes’.  I am in Glasgow, for I am in two places, and one of them is in Glasgow.  But while true, it would be utterly unhelpful and disingenuous for me to answer in the affirmative: my speaking thus would not help you help me in my plans to bring my adult self to my infant self.  And while it would be false, it would nevertheless be completely helpful and appropriate to say ‘No, I’m not in Glasgow, I’m in Leeds’.  That’s false, because I’m both in Glasgow and in Leeds; but it’s a good thing to say because it communicates to you the information that you want: that the location I have in virtue of my adult self having travelled back to this time is in Leeds, even though I also have a location in Glasgow in virtue of my also having been an infant at this time.  Likewise, when I find my infant self and claim to be taller than he is, what I say is strictly speaking false: everything true of him is true of me, for we are identical, and so every height relation he bears to a place at this time (or every way he has a height) is also a height relation I bear to a place at this time (or is also a way I have a height).  Nonetheless, the false contrastive claim is a sensible thing to say and can impart useful information: it tells you that the height I have in virtue of having travelled back to this time as an adult is greater than the height I have in virtue of having been born at this time.

God the Son wasn’t speaking to metaphysicians, he was speaking to the folk.  The data that needs to be recovered is that he said something good: something that would impart good, true, information to his listeners.  Even given endurantism, his utterance does this on the time-travel story, despite being strictly speaking false.  Everything you can say about God the Son’s powers at t0 you can say about God the Father’s powers at t0, since they are the same thing.  Nonetheless, you learn something true and useful from the Son’s utterance that the Father is greater than he is: you learn that it is in virtue of this one being having come back in time after having changed that he is omnipotent at that time, and in virtue of him having begotten his earlier self at that time that he lacks omnipotence at that time.  The Son could have conveyed this information with a literally true utterance if he had spoken in a more metaphysically perspicuous manner; but since he was speaking to the folk and not to a select audience of metaphysicians, it’s perfectly understandable why he didn’t.

The Son’s utterance that no-one can come to the Father except through him is true.  As would have been the utterance that no-one can come to the Father except through the Father.  But while both true – and while in some sense they both say the same thing – the latter is not as good a thing to say as the former.  For the latter claim fails to impart the vital information conveyed by the former: that it is virtue of God having had his earlier properties that he is able to bring you to a being that is so far beyond you, namely the all-powerful being he becomes.  So it’s no surprise that the Son makes the former pronouncement and not the latter: far from being less informative, it is in fact more so.

And so I think we have a model of the relationship between the Father and the Son that adequately accounts for our initially recalcitrant data.  But what of the third member of the Trinity, the Holy Spirit?  Well, it would be easy to account for the third member in just the same way: have God travel in time twice.  Recall the story of me giving birth to myself: at the time I was born there were three versions of me about (the father, the mother after I had a sex change, and the child the first two versions of me gave birth to), because I travelled back to that time twice as well as being born there.  Thankfully, the Bible is pretty silent on the relationship between the Holy Spirit and the Son and the Father, so you can fit it in as you wish once you’ve got the general recipe.

Let me close by considering an objection.  One might object at the very idea of God starting out life as a limited being and only growing to be omnipotent over time.  That might be thought to violate the claim that it is essential to God’s very nature that he is omnipotent.  Care is needed here, however.  It’s perfectly compatible with the above account that God is essentially omnipotent in that it is of his essence that he grow to become omnipotent.  And God is around and omnipotent right from the beginning of time, remember.  He’s also around and limited at that time, but he’s omnipotent at that time as well, because his later self travelled back to then.  And this might also be of God’s essence: perhaps he has to so travel back (after all, if he didn’t travel back to beget himself, where would he come from?).  And so it’s compatible with the proposed account that God is essentially such as to become omnipotent, and that he is essentially such as to be omnipotent at all times.  What it’s not compatible with is the claim that he’s essentially such as to be never not omnipotent, since on this account he is sometimes both omnipotent and not omnipotent.  I doubt our intuitions regarding God’s essence are so fine-grained that this is determinately what we have in mind when he say that he is essentially omnipotent, so I’m unconcerned about biting this bullet.

Tuesday, June 05, 2012

Metaphysical Indeterminacy workshop: schedule

Update on the upcoming workshop for the Metaphysical Indeterminacy project.  The schedule will be:

Wed 13th June:
1.15-1.30pm: Registration in the philosophy foyer
1.30-3pm: Cian Dorr (Oxford): Semantic Plasticity
3-3.15pm: Break
3.15-4.45pm: Carrie Jenkins (UBC): Justification Magnets and Indeterminacy

Thur 14th June:
9.30-11am: Daniel Nolan (ANU): Indeterminacy and Essence
11-11.15am: Break
11.15am-12.45pm: Patrick Greenough (St Andrews): Evans' Argument

All the talks will be in BG36 in the philosophy department.