2 questions

Here are two questions I’d appreciate any thoughts on. Firstly, I’ve recently detected an apparent tension in my beliefs. In my paper for Phil Compass on the grounds of necessity, I argue that the Lewisian realist needn’t be worried about the epistemological objection. The objection goes: how could we know what’s (merely) possible if what’s possible is what’s true at a spatially-temporally isolated concrete world – such worlds do not interact with us causally, so how can we come to know what they’re like? Lewis responds by saying that causal interaction is necessary only when the subject matter is a contingent truth – when the claim to be known is a non-contingent matter, causal acquaintance with what the claim is about is not necessary even when the claim is about the realm of concreta. It’s not obvious to me that this is a good reply, but I thought Lewis had a simpler reply available: metaphysical priority is not conceptual priority. To say that what it is for it to be possible that p is for p to be true at some world does not commit us to saying that our epistemic access to the fact that p is possible must go via epistemic access to there being a world at which p. The Lewisian realist needn’t claim we have any way of discovering what’s true at a world independently of discovering what’s possible. Why can’t the Lewisian simply say she knows there’s a world where there’s a talking donkey because she knows that there could be talking donkeys (here appealing to whatever story about modal epistemology that any realist appeals to), and she knows that everything that could be the case is the case at some world (and here she cites the familiar Lewisian reasons for believing that claim)? What’s the problem?

That still seems convincing to me. Here’s my problem. I also find convincing an epistemological objection to consequentialism: were consequentialism true we couldn’t know what’s right or wrong because we can’t know what the full consequences of our actions would be. And it doesn’t seem to me in the least bit satisfying for the consequentialist to say: I know that murdering X will have the worst consequences because I know that murder is wrong – metaphysical priority isn’t epistemic priority, so my knowledge that it is wrong can ground my knowledge about the consequences even though what it is for it to be wrong is for it to have the worst consequences.

What I’d like is for the two cases to be disanalogous so I can consistently do what seems to me intuitive: hold the epistemological objection to consequentialism and reject the epistemological objection to Lewisian modal realism. I haven’t been able to convince myself that they’re analogous yet, so any thoughts on this are welcome (even if they’re of the form: they’re obviously analogous, and you’re wrong about the epistemological objection to ____). (Incidentally, I barely know the literature on consequentialism, so if anyone knows what consequentialists say about the epistemological objection, please enlighten me!)

Question 2. I was reminded by Brian’s post about the autonomy in logic issue. There’s a thought that every logical truth should be provable using only the rules governing the connectives in that truth. This is meant to be bad for classical logic because there are classical tautologies like Pierce’s law where the only connective is the conditional but one can’t prove Pierce’s law using only the rules for the conditional. I was thinking about this briefly, and I couldn’t see how the objection could possibly be right. We can do classical logic with just one logical connective: the Sheffer stroke, e.g. Every wff of classical logic – a fortiori every theorem – has a translation into a sentence statable using only the Sheffer stroke, and the translations of the theorems will be provable using only the rules governing the Sheffer stroke, as those are the only rules you have. But it can’t be the case that the acceptability of a logic depends on what connectives you allow yourself to use to state its theorems. The defenders of the objection are obviously going to be unimpressed with such a simplistic response, so my question to those who know more about this than me (= those who know than is written in this paragraph!) is: why not?

Substitutional Quantification and Supervaluations

(Cross-posted with Matters of Subtsance.)

Let U be the (universal) substitutional quantifier: its truth-conditions are

"UxF(x)" is true iff, for every name n, "F(n)" is true.

(Normal quotes are doing double-duty as quasi-quotes here.)

Peter van Inwagen has an argument that we can't understand substitutional quantification. It goes like this:

(1) We can't understand a sentence unless we can specify what proposition it expresses.
(2) The only proposition we know of with the right truth-conditions to be expressed by "UxF(x)" is the proposition that, for every name n, "F(n)" is true. (Call this proposition "UU".)
(3) Friends of substitutional quantification say that UU is not what is expressed by "UxF(x)".
(4) There are no other candidates to be the proposition expressed by "UxF(x)".
(5) So if friends of substitutional quantification are right, we can't understand "UxF(x)".

I want to respond to this argument, but I don't know whether my response rejects premise (1) or (4). So I'll outline the basic idea, and then maybe someone can help me know which premise I'm rejecting.

Suppose some sort of supervaluationism is the right treatment of vagueness, and set aside higher order vagueness. Then a sentence like "Fido is red" doesn't express a proposition simpliciter; rather, it expresses a proposition relative to every precisification of "red".

(Since we can understand "Fido is red", this alone might be enough to lead us to deny (1). But it's not clear how this denial gives us any positive reason to think we should be able to understand substitutional quantification. I want to aim higher. So let's press on.)

The truth-conditions for this sentence with the determinacy operator are:

"Det(Fido is red)" is true iff "Fido is red" is true on every precisification of "red".

Now, we can think about precisifications in a number of ways. One of them is an explicitly semantic way: the precisifications of a term are the precise meanings it can have. But another is a bit more syntactic, relating more precise terms to less. If we have semantic precisifications, we can easily define syntactic ones as follows: T is a syntactic precisification of T* iff T's semantic value is a semantic precisification of T*. If we don't have semantic precisifications, we might take the syntactic ones as primitive, or we might be able to define them some other way (maybe by appealing to metalinguistic predicates like "admits of borderline cases" and some others).

If we have the syntactic understanding of precisification, then we have the truth-conditions

"Det(Fido is red)" is true iff "Fido is R" is true for every term R that is a precisification of "red",

which look remarkably similar to the ones we had for the substitutional quantifier.

So here's my basic idea: think of "x" as a maximally vague name --- a name such that every precise name is a (syntactic) precisification of it. Then think of "U" as a determinacy operator. This gives us essentially the truth-conditions we want.

How does van Inwagen's argument look now, with this understanding of the substitutional quantifiers? That depends, I think, on what we say about the proposition expressed by "Det(Fido is red)". I think there are very good reasons to think that this sentence does not express the proposition that "Fido is R" is true for every term R that is a precisification of red. (One very good reason is that it won't embed right at all --- it might be necessary, say, that Det(Fido is red), even though it certainly isn't necessary that "red" is even a word, much less that it has precisifications. And these thoughts extend to the truth-conditions that go via semantic precisifications, too.) But are we in any position at all to specify a proposition it expresses?

Here I don't know what to say, and this is why I don't know which premise I reject in van Inwagen's argument. On the one hand, maybe we have some recipe for specifying a proposition expressed by "Det(Fido is red)". If so, then we can use the same recipe to specify one expressed by "UxF(x)", and I deny premise (4). Maybe we think "Det(Fido is red)" expresses the conjunction of all the propositions expressed by "Fido is R", where R is a (syntactic) precisification of "red", for instance. If so, then we can say that "UxF(x)" expresses the conjunction of all propositions expressed by sentences of the form "F(a)" for some name "a".

On the other hand, maybe we can't specify any proposition expressed by "Det(Fido is red)". (Maybe we dislike the conjunction proposal for both the "Det" and "U" cases because we think it misses out on the "that's-all"-ish nature of the quantifications involved in the truth-conditions.) Nonetheless, I think it's entirely clear that we understand "Det(Fido is red)". And I also think (but I haven't argued for it) that one way we can come to understand a vague term by learning a recipe for figuring out what its precisifications are, so we can understand what the "x" in "UxF(x)" is doing. But in this case, "UxF(x)" is essentially just "Det F(x)"

There's a lot of details I've left out --- stuff about variable-binding, the viability of the syntactic characterization of precisifications, how to think of modally embedded substitutional quantifications, and so on. But setting these techy details aside, I'm wondering what the right thing to say about the argument is. Or, more to the point, I'm wondering what we should deny when we run a parody argument for our inability to understand the sentence "Det(Fido is red)".

Thoughts, anyone?

Protect research in the UK: sign this petition!

If you think the allocation of research funding should be decided on the basis of research excellence and not on the short-term and narrowly construed 'impact' it's likely to make (as decided in part by non-specialists), then please sign this petition!

CAI and SCQ

I've posted a new and expanded version of my paper arguing that composition as identity doesn't settle the special composition question. It's here; thoughts welcome.

The Northern Institute of Philosophy

The Northern Institute of Philosophy - a research centre at the University of Aberdeen directed by Crispin Wright dedicated to the core areas of analytic philospohy - now determinately exists! It is indeterminately identical to the centre I was a member of during my PhD, so is metaphysically interesting in its own right!

Their website is here, and they have a blog here. An exciting future no doubt awaits!

The REF and 'impact'

We don't often delve into the political side of things on MV, but this is an extremely important issue for philosophy in the UK. As many will know, there used to be the RAE: the research assessment exercise. This consisted of a panel of subject specialists reading and making a judgment on the (self-nominated) four best papers of every academic in the country put forward by their department (in practice, basically all the research active staff). The resulting department ratings controlled how much money they would get. Like any system, it of course had its problems, but it was beneficial in many ways. Departments could no longer afford to simply hire the person with the Oxbridge degree and ignore the non-Oxbridge person with a stack of papers in good places - it made hiring more meritocratic.

The RAE is no more. It is being replaced by the REF. It does not look like a change for the better. One bad change is that the panels are to be more coarse grained: it will no longer be simply philosophers judging philosophers, etc. But the most disturbing issue is that 25% of the grade a paper gets is now going to be on the 'impact' it makes. At least, they *say* it will be determined by the impact it makes: in practice, of course, it can't be, since no-one has a crystal ball - so the least they could do is be honest and tell us straight that 25% of the grade will be determined by its short term impact. At least wear the short-term-ism on your sleeve if that's what we're aiming for now!

"How do you determine the impact of a specific paper anyway?" one might ask. Yeah, good question. These guys need to read their Quine! The simple counterfactual account is obviously problematic (even putting aside epistemic problems). All signs point to a focus on narrow, direct, short term impact being what's going to be relevant. A disaster!

Alan Weir wrote on open response to the REF that's available here. It's well worth reading: I want to quote a section.

"The taxpayer can see how funding researchers to investigate solutions to
some immediate problem, a virus say, can be justified. But how can the
funding of pure research be justified? Well, since the research is carried
out for its own sake, those involved will think that centuries-long
traditions of transmitting a body of work of enormous intellectual,
cultural and artistic merit from one generation to the next is of great
value in its own right. But to the sceptical taxpayer we have a very
potent additional point to make. What if Albert Einstein, Max Planck,
Werner Heisenberg, Erwin Schrödinger, in trying to determine how the
mysterious sub-nuclear world of quantum physics worked, had been
constrained and directed by whether their research satisfied short-term
impact criteria? What, to move closer to my own area, if Gottlob Frege,
Bertrand Russell, and Kurt Gödel and others who devoted their lives to
investigating the nature of mathematical truth, logical consequence and
the light formal artificial languages can shed on them (and with no
thought to the possibility of automated reasoning machines of the type the
philosopher Leibniz had sketched) had been required to demonstrate the
impact their researches would have outside academe? Then no quantum
physics and modern micro-electronics, no artificial languages, recursion
theory and computer science; we would have likely remained at the level of
Victorian science and technology and all the practical, medical and
intellectual advances which microelectronics and computing have given us
would not have emerged. Even taxpayers with no desire at all to be
Socrates dissatisfied can see the enormous impact (though not on the
ludicrously short scale of ten to 15 years) these
investigations, driven by pure intellectual curiosity, have made by
comparing today’s technology with late Victorian.

It is essential to grasp that the unintended consequences which emerge
from pure disinterested research have arisen because they were precisely
that: the research was not being directed at all to go towards immediate
practical goals."

Hear hear! The 'impact' research makes is both a long term issue, and a holistic one: one simply cannot separate out the impact made by the research activity of mankind and parcel it out paper by paper. To try to do so is simply nonsense, especially on the ridiculously short time scale it would need to be for it to be relevant for funding purposes.

Let's hope sense wins out and the research community in philosophy and elsewhere is not forced to bow to the whims of petty short term thinking, looking only to immediate and foreseeable commercial gain.

Update: There's a good post on this at Logic Matters.

Update 2: Of course, it's not just philosophers who should be worried. The Guardian quoted some reasonably concerned physicists too - even the subjects where you'd expect it would be easier to demonstrate 'impact' still, sensibly, don't want to have their research agenda to be driven by that.

Fine on essence

I've put online a draft of a paper I'm writing for Phil Compass on the grounds of necessity. Comments on anything in it are welcome, but I'm going to post here some of the stuff I say about Kit Fine's reduction of modality to essence, since I'd especially welcome thoughts on that. So here's Fine:

"Necessity has its source in those objects which are the subject of the
underlying essentialist claim. . . We should view metaphysical necessity
as a special case of essence. . . . The metaphysically necessary truths
[are] . . .the propositions which are true in virtue of the nature of all
objects whatever."

Here are three thoughts (none intended as anything like insurmountable objections, just things to think about):

1) Prima facie, the view seems to require us to accept the existence of things like properties and relations, and thus appears to be incompatible with nominalism. For what entity can we plausibly say has a nature such as to guarantee the
truth of ‘If there are some things, there is a set of those things’ if not the
relation being a member of? No collection of actual individuals guarantees the
truth of that, because the claim says something about what happens no matter
what individuals are around.

2) If it’s necessary that there couldn’t be certain (kinds of) individuals
(universals, say, or God) then we must admit that some of the things that exist
have natures that exclude the existence of other things. You might find this
harder to accept than the claim that some things have natures that guarantee
the existence of other things. (Cf. the familiar objection to admitting
truthmakers for negative existentials: intuitively, they are true because some
things don’t exist, not because some thing does. Similarly, impossible
existents are impossible, intuitively, because there’s something about them
that’s impossible, not because, e.g., there’s something else whose essence is
such as to make them impossible.)

3) It’s easy to see how the essence of an entity e can account for the necessity of
a conditional the antecedent of which says that e exists. So my essence
grounds the truth of, hence accounts for the necessity of, ‘If Ross exists, he is
a human’. From this, it’s easy to see how unconditional necessities can be
grounded if the thing whose essence accounts for its truth has existence as part
of its essence. So were I an essential existent, my essence would account for
the necessity of the antecedent of the above conditional as well, and hence
account for the necessity of the consequent. But we might want to allow for
cases where an unconditional necessity is ‘multiply realized’ in the following
way. Suppose 2+2=4 is actually true in virtue of the essence of the numbers 2
and 4. So we account for the necessity of ‘If the numbers exist, 2+2=4’. But
it’s not just conditionally necessary that 2+2=4, ‘2+2=4’ is itself necessary.
But on this view, that’s not because the numbers exist necessarily: on this
view, while our actual world is Platonist, and mathematical truths are true
because of the numbers, structuralism is possibly true and ‘2+2=4’ is true in
virtue of the essence of certain structures, and maybe in some worlds there are
brute mathematical laws, and ‘2+2=4’ is true in virtue of these laws. So there
are multiple possible grounds for the arithmetical truth, and the truth is
necessary because it’s necessary that there is some ground or other. But what
actual things have essences such as to ground this last necessary truth? The
worry is that Fine can only account for conditional necessities or
unconditional necessities which are unconditionally necessary because there is
some essential existent that accounts for their truth in any possible circumstance.

Jobs at Leeds

Leeds will be hiring two new positions in the upcoming hiring round, at either lecturer or senior lecturer level (for US readers: roughly equivalent to a tenured assistant prof and an associate prof, respectively). Details below.

University of Leeds
Faculty of Arts
Department of Philosophy

2 Lectureships/Senior Lectureships in Philosophy
(Available from 1 September 2010)

The Department of Philosophy is one of the largest Philosophy departments in the UK, with over 30 academic staff, a large intake of undergraduate and postgraduate students and a vigorous research culture. It received a maximum 24 in the last Teaching Quality evaluation and in the 2008 Research Assessment Exercise 65% of our research was rated "world class" or "internationally excellent" (matching the percentage of leading UK philosophy departments such as Oxford and Cambridge). The Department has distinctive strengths in aesthetics, history and philosophy of science, metaphysics, and moral philosophy.

The ‘Area of Specialisation’ for this position is open, within Philosophy. Potential candidates are strongly advised to consult the department’s website for details of its research and teaching programmes.

The position will incorporate undergraduate and postgraduate teaching, some thesis supervision, and usual non-teaching duties. With a strong record of research publication, the successful candidate should be qualified to masters level or equivalent. A PhD prior to application and teaching experience are strongly preferred for a Lectureship and are essential for a position at Senior Lecturer level.

For general information see http://www.philosophy.leeds.ac.uk/

Lecturer - University Grade 7 (£32.458 – 35,469 p.a.) or University 8 (£36,532 – 43,622 p.a.) Senior Lecturer - University Grade 9 (£44,930 – 52,086 p.a.)

Informal enquiries to philosophy-hod@leeds.ac.uk or tel: +44 (0)113 343 3260

To download an application form and job details please visit www.leeds.ac.uk and click on ‘jobs’. Alternatively these may be obtained by email from recruitment@adm.leeds.ac.uk or tel: +44 (0)113 343 5771.

Job ref 318050 Closing date Wednesday 11th November 2009

Presentations and Interviews will take place on Monday and Tuesday 18th and 19th January 2010

Applicants should submit the completed application form, full CV, and a writing sample (of no longer than 25 pages) by the closing date of 11th November.

Presentism, Truthmakers and Theoretical Virtues

I’m just back from the BSPC where I gave my Truthmaking for Presentists. I got loads of good questions of and comments, but wanted to comment on one of them. In the paper I argue that truthmaker theory can be contingently true and hence that it’s no immediate objection to my view if there are possible presentist scenarios in which my account doesn’t work, so long as we can reasonably believe that they are not actual. (The scenario in question discussed in the paper is a presentist world with an infinite past.)

One of my commentators, Caspar Hare, was pushing me on whether I thought it was similarly okay for the truthmaker principle to simply be true now. He was expecting me to say yes – but I say no, it must be true always; and he was rightly pushing me to say why one should demand that the principle be true at all times but not at all worlds when one holds a view that treats times and worlds analogously in holding that only one of each (the present time, the actual world) is real.

For me the reasons to be a truthmaker theorist concern theoretical virtues. Truthmaker theory is the theory that all the brute truths are truths about what there is, and this is theoretically more virtuous than theories that take as brute truths not only about what there is but also truths about what there was, could be, should be, etc, as well as truths about how things are, what laws hold, etc, etc. If truthmaker theory is true, God’s language only needs names and an existence predicate: that’s ideologically simpler, and hence more virtuous (other things being equal), than theories which require God to be able to make predications, express tensed facts, etc.

I think that in the absence of further information, if the only reason to believe a theory is that it is theoretically virtuous, then we should take that theory to be at best contingently true. There’s no inconsistency in a theoretical virtue selecting a necessarily true theory, but we’d need some reason to think that it does in any particular case. In general the world needn’t have cooperated with what is theoretically virtuous: being guided by simplicity, parsimony etc might have taken us badly wrong – we just hope it doesn’t actually do so. That’s why I only hold truthmaker theory to be a contingent truth. (It’s also why I hold the contingency of composition, and the contingency of whether there is a fundamental level.)

But it seems to me that satisfaction of the theoretical virtues makes a demand on how the world is across times, not just at the present time, even if the present is all that is real. Suppose we’re faced with two theories, T1 and T2. T1 says that there are always 10,000 things. T2 says that there are now only 100 things but that at all other times there are billions. It seems to me that the presentist doesn’t get even a pro tanto reason to accept T2 on the basis that it says that there are fewer things in reality. (I’m assuming quantitative parsimony is a virtue – replace talk of number of things with number of kinds of things if you don’t.) Sure, the present is all that there is, and T2 says that there are presently 100 things whereas T1 says that there are presently a hundred times as many things. But the presentist should still be moved, I think, by the fact that according to T2 reality just was, and is soon to be again, massively more unparsimonious than T1 says it is. The fact that those times aren’t real shouldn’t make us worry any less about that. (By contrast, if T3 and T4 agree on what actually exists but T4 says there are more possibilia than T3 does, this only gives us even a pro-tanto reason to prefer T3 if we are realist about possibilia.)

I think that what’s driving this thought is an idea that Kit Fine pushes in his fantastic paper ‘Tense and Reality’: that everyone should think of non-present times as part of the same ‘all encompassing reality’ whereas only the realist about possibilia should think that about worlds. Now Fine takes that as a reason to deny that the present time is privileged, and so to be a non-standard realist if you’re going to be a realist about tense; but I think that one can still accept that thought and accept a privileged present. One just needs to accept that what’s going on at other times is relevant to how we judge theories in a way that what’s going on at other worlds is not (at least, not in the same way).

So parsimony doesn’t tell the presentist to accept T2 over T1, and if the truthmaker principle is only true now it doesn’t tell the presentist to be a truthmaker theorist. The virtues of truthmaker theory are only obtained if it is always true; by contrast, whether it is necessarily true are neither here nor there, as far as securing those virtues is concerned.

Graduate conference in metaphysics

See following call for papers for the CMM graduate conference
__________________________________________________________________

The Centre for Metaphysics and Mind at the University of Leeds is
hosting the 4th Annual CMM Graduate Conference on Friday 4th
September.

Submissions are welcome on any area of metaphysics. Metaphysics should
be broadly construed to include not only traditional metaphysical
topics, but also the metaphysical aspects of e.g. philosophy of mind,
philosophy of physics, philosophy of religion, and aesthetics.

Submissions of any length up to 5,000 words will be considered.

Each paper presented at the conference will be followed by a response
from a member of academic staff or PhD student from the University of
Leeds Department of Philosophy.

As with last year's conference we hope to be able to pay some or all
of the travel and accommodation costs for those people whose papers
are accepted. (This is dependent on successful funding applications.)

Please submit complete papers, preferably by e-mail, to Joanna
Pollock, joeykpollock@googlemail.com. Please mark your submission
clearly as such. Receipt will be acknowledged asap.

All papers should be suitable for blind review (we cannot guarantee
anonymised refereeing if your paper is not suitably anonymised).
Please include a cover page with title, abstract and contact details.

Deadline for receipt of submissions is Sunday 19th July 2009.

Decisions will be made by Monday 10th August 2009.

For more general details on the conference please consult:

http://www.personal.leeds.ac.uk/~phsk/cmmgc09/index.htm

or e-mail Duncan Watson at phl5dw@leeds.ac.uk

Composition as identity does not entail universalism

In my Contingency of Composition paper, I deny the commonly held claim that composition as identity (CAI) entails universalism about composition. (The entailment is defended by Sider, Merricks, et al.) My basic thought was: CAI says just that a complex object is identical to its parts – that tells us only that when you’ve got a complex object, it is identical to its parts, and this is silent about whether or not for any collection of objects there is such a complex object that they are identical to. If many-one identity makes sense then, prima facie, it makes sense to claim that for some collections of objects there’s a one that they are identical to, and some collections of objects such that there’s no one object that they are identical to. All CAI tells us is that it’s all and only the first collections that compose. To assume that every collection composes is just to assume that for any collection of objects, there’s a one to which they are identical. Why would I accept that if I doubted universalism?

In denying the entailment, I need to respond to an argument that both Sider and Merricks give for it. They argue as follows: Suppose (for reductio) the Xs don’t compose. They could do. Go to the world where they do (w). In w, there’s a one, A, that’s identical to the Xs. Given the necessity of identity, A is actually identical to the Xs. So the Xs actually compose A. Contradiction. Formally:

1) ◊(Xs=A)
2) ◊(Xs=A) -> □(Xs=A)
3) @(Xs=A)

In my paper I attempted to resist this argument with some pretty tricky moves – and while I still think they’re right, I think I haven’t exactly convinced the world! (See the earlier discussion on this blog) But I think I can actually make the point more simply than I did then.

The argument aims to prove that the Xs are actually identical to A. Thus, there is a one that the Xs are identical to: A. So since to compose is to be identical to a one, the Xs compose. But wait! All the argument shows is that it’s actually true that the Xs are A. Where do we get the claim that there’s a one that the Xs are identical to? This follows, obviously, if A is actually a one. But where does that claim come from? All we know is that A is possibly a one. Ex hypothesi A is a one in the world in which the Xs compose. But we can only conclude that A is actually a one – and hence that there’s a one that the Xs are actually identical to – if we have the assumption that anything that is possibly a one is necessarily a one. But what right do we have to make that assumption? If we’re leaving open the possibility that there’s a many that’s not a one but could be (and at this stage we must, lest we beg the question), we should also leave open the possibility that there’s a many that is a one but might not be. Since the many is the one, this is a one that might not be a one: a one that is a many, but that might have been a mere many – a many that is identical to no one. If the Xs don’t actually compose this is the status we should think A has in the world in which they do compose. So sure A is actually identical to the Xs: but A is actually just a name for the plurality, a plurality that don’t actually compose. A is only a one in the worlds in which that many do compose. And we’ve been given no reason to think we’re forced into thinking that our world is one of those.

The Trinity and contingent identity

I got thinking about the Trinity after the workshop on the metaphysics of theism at Leeds last week, and I got to wondering: has anyone ever suggested that the Trinity is a case of contingent identity? (The good thing about a blog is you can put out those ideas that are too weird for publication! All my thoughts on the philosophy of religion are a proper subset of that category.)

So forget the Trinity for the moment and focus on the father's relationship to the son: the idea is that they are actually identical, but contingently so, and that the father is a necessary existent but the son a contingent existent. In every world in which the son exists, he is identical to the father, but there are worlds in which the father exists and is not identical to the son because there are worlds in which the son does not exist (for the son to exist depends on an act of will on the part of the father, and he might not have so willed).

So there is of course a very tight connection between the father and the son: strict numerical identity - it doesn't get much tighter! Thus vindicating Jesus's claim that that father and he are one. But we can also quite easily, on this view, make sense of Jesus's claim that the father is greater than he is: he's a mere contingent existent, the father a necessary being - that's good grounds for saying that the father is greater.

How to fit in the spirit? Well perhaps the spirit is also a contingent existent, and also actually identical to the father (and, by transitivity, the son), but that there are worlds with son but no spirit and worlds with spirit but no son. So the idea is that although the father, the son, and the spirit are each numerically identical to the others, we can distinguish them by their differing modal profiles. For any two, while they're actually identical, they might not have been. But monotheism is easily seen to be a necessary truth, on this view (whereas other views of the Trinity threaten to commit us to tritheism): necessarily, there is only one God, for necessarily any divine being is numerically identical to the father.

Objection: how can they be numerically identical if they have differing modal profiles? Reply: well, we all know the contingent identity theorist has to resist the Leibniz law argument from differing modal profiles to numerical distinctness. Whatever story they're going to tell to make sense of contingent identity in general, let them tell it here.

Objection: but isn’t there a difference in non-modal properties as well? The father is atemporal, the son temporal, the son human the father not, etc? Reply: okay, we’re going to have to say something odd here. Perhaps we just deny the atemporality of the father, or perhaps we say that God is atemporal qua father but not qua son, etc (and hopefully unpack that and say what it means!). But every view of the Trinity ends up saying something a bit odd at this point – it’s not clear that there’s a particular objection to the contingent identity view here.

So, does anyone know if this has been discussed before, or see any problems with it that aren’t faced by all accounts of the Trinity?

(Posts on sane topics will resume once marking season is over, I suspect!)

Routledge Companion to Metaphysics

The Routledge Companion to Metaphysics is now out! I'm very proud of this: I think our contributors all did an excellent job, and the volume looks excellent.

It's divided into three sections: the history of metaphysics, ontology, and metaphysics and science, and contains 53 original essays. I hope and believe it'll be a useful work of reference for the foreseeable future. You should buy it!

New research centre in Scotland!

Exciting news for philosophy in Scotland! Crispin Wright has accepted an offer to found and direct a new philosophical research centre at the University of Aberdeen. The centre will ‘go live’ Sep 1st 09, and is provisionally named ‘The Northern Institute of Philosophy’.

The NIP’s areas of remit will be: Epistemology, Formal Logic, Philosophy of Logic, Philosophy of Language, Philosophy of Mathematics, Metaphysics, Philosophy of Mind, and the History of Analytical Philosophy. A number of appointments will be made of various categories in the near future, and a bunch of the Leeds faculty will be involved as Associate Fellows, and in other respects.

Arbitrary Reference

I posted a while back toying with a view of vagueness whereby there was a sharp cut-off in any sorites series as a result of there always being a unique most meaning among the candidate meanings (i.e. those that fit equally well with usage) for any vague expression; since naturalness is a reference magnet – and since it is ex hypothesi not trumped by usage – this is the meaning we will in fact mean, thus determining that the cut-off is where it is. (I further toyed with the idea that it is ontically indeterminate which meaning is the unique most natural, thus yielding the conclusion that it’s determinate that there’s a sharp cut-off in the sorites series but that it’s ontically indeterminate where it is – but forget about this complication for now.)

I’ve also been thinking about this with respect to arbitrary reference. What’s going on when we reason as follows? Let n be an arbitrary multiple of 4. n is a multiple of 2, all multiples of 2 are even, so every multiple of 4 is even. In particular, what, if anything, is referred to by ‘n’ throughout? Maybe it doesn’t refer; but then it’s hard to see how the sentences could be truth-apt, and we get a kind of Frege-Geach problem. Maybe it refers to a special kind of entity: the arbitrary multiple of 4; but that’s kind of weird. Ofra Magidor and Wylie Breckenridge have a really interesting paper where they argue that n actually refers to some particular multiple of 4 – we just cannot know which one. But in virtue of what do I refer to this particular multiple of 4 rather than some other? In virtue of nothing, they say: this is a brute fact. The semantic facts, on their view, are not fixed by the non-semantic facts: all the non-semantic facts could have been just the same but you have referred to some other multiple of 4 by ‘n’. I don’t like brute semantic facts, but I like a lot about their account, so I am quite attracted to extending the above account of vagueness to cases of arbitrary reference: ‘n’ refers to the most natural arbitrary multiple of 4. (Psst! – and it’s ontically indeterminate what this is. But again, forget this just now.)

There are two problems, one of which is encountered by both Magidor and Breckenridge and myself, the other of which might be thought to tell in favour of Magidor and Breckenridge’s view over my variant. I’d appreciate any thoughts on what I have to say about these.

First the common problem. Any view that takes us to genuinely refer to an F when we aim to refer to an arbitrary F has to have something to say about the case where there can be no Fs. For example, suppose we reason as follows. Let n be an arbitrary even prime greater than 2. n is (because it’s even) divisible by 2. So n is divisible by a number other than itself or 1. So n is not prime. Reductio: there is no such n. This chain of reasoning is perfectly good; but it’s obviously hopeless to take ‘n’ to refer to any even prime greater than 2, precisely because there are no such things. (I guess we could go Meinongian, and claim that there are such things, and ‘n’ refers to one, but that n doesn’t exist. But let’s not.) So what’s going on in this case? This is a case where those who postulate special entities as the referents in the cases of arbitrary reference – the arbitrary F – are at an advantage over those who take us to refer to an F; for if the arbitrary even prime greater than 2 isn’t really an even prime greater than 2, there can be no objection to its existence on these grounds. But of course, such views face other problems: such as, if the arbitrary F isn’t an F, what is it? I think we should treat cases like this as not really being cases of arbitrary reference after all. Despite their surface similarity to such cases, these cases, I suggest, are really reductios on the hypothesis that we have a case of genuine reference. So when we say ‘Let n be an arbitrary even prime greater than 2’, I suggest we are really supposing for reductio the hypothesis that ‘an arbitrary even prime greater than 2’ refers. Then, of course, we need some principle that lets us semantically descend, and conclude that there are no even primes greater than 2 if that expression cannot refer.

Now to the other problem. While I might not know what the most natural F is when I refer to an arbitrary F, there are some things I do know. I do know, for example, that if I refer to an arbitrary property I do not refer to grue, because grue is less natural than green. So when I say ‘Let F be an arbitrary property’, I can conclude that F is not identical to grue. But can’t I then conclude that all properties are not identical to grue, for isn’t one of the rules we’re trying to capture the one that says that if x is an arbitrary F and x is G then all Fs are G? But this rule would then take us wrong, for it’s not true that all properties are not identical to grue, for grue is identical to grue.

If this is a problem for my view, however, there is as much of a problem with Magidor and Breckenridge’s view. Indeed, any view that takes you to refer in a case of arbitrary reference has such a problem, including views that take you to refer to a special kind of entity (the arbitrary F), for the above rule would tell you to infer that all the Fs have the property of having being referred to by you when you said ‘Let n be an arbitrary F’. If I, at time t, say ‘Let n be an arbitrary number’ then, if ‘n’ refers – no matter what it refers to, or how the reference fact is determined – then n has the property having been referred to by me at t. If we follow the rule that tells us to infer that all Fs are G if the arbitrary F is G, it follows that all numbers were referred to by me at t. This is false: either I referred to a particular number, or to a special entity that is the arbitrary number, but I certainly didn’t refer to each number.

So anyone who takes cases of arbitrary reference to really be cases of reference can’t admit that rule in full generality. But views which take us to refer to an F (rather than to a special entity, the arbitrary F) when we say ‘Let a be an arbitrary F’ obviously needed to restrict this rule in any case. Suppose I say ‘Let n be an arbitrary multiple of 4’. We want to be able to reason as follows: n is even, hence every multiple of 4 is even. But suppose, as a matter of fact (putting aside why this is the case), ‘n’ refers, arbitrarily, to 28. 28 is a multiple of 14. So can’t we now conclude, mistakenly, that all multiples of 4 are multiples of 14? The rule had better be restricted so that we cannot so infer. Magidor and Breckenridge respond to this problem by modifying the rule to say that we can only conclude that every number is F if we can prove that the arbitrary number n is F. Because you can’t know that n is 28, you can’t prove that n is a multiple of 14, and hence you can’t conclude that all multiples of 4 are multiples of 14.

I think Magidor and Breckenridge are basically right to restrict the rule so that the properties we can conclude that all Fs have aren’t the ones that n has if n was our arbitrary F but rather just those ones that we can prove that n has from a certain basis. But the basis can’t be the properties we know that n has: for while that would deal with the problem immediately above, since we can’t know that n, our arbitrary multiple of 4, is a multiple of 14, even if it is, this won’t deal with the prior problem, since we can know that n was referred to at t when I said at t ‘Let n be an arbitrary multiple of 4’. I think instead we should restrict the rule as follows: if a is an arbitrary F, then if you can prove that a is G from facts that are true solely in virtue of a being an F (i.e. excluding those facts that are true in virtue of a being the particular F that it is), conclude that all Fs are G. 28 isn’t a multiple of 14 in virtue of being a multiple of 4, it’s a multiple of 14 in virtue of being that particular multiple of 4, but it is even in virtue of being a multiple of 4, and that’s why we conclude that all multiples of 4 are even but why we can’t conclude that they’re all multiples of 14. Nor was 28 the referent of ‘n’ solely in virtue of being a multiple of 14: on my view, it is true in virtue of being the most natural multiple of 14; on Magidor and Breckenridge’s view it is not true in virtue of anything. Either way, the move to ‘all multiples of 14 were referred to by ‘n’ at t’ is blocked.

This also lets me respond to what would otherwise have been an advantage of Magidor and Breckenridge’s approach over my own (I owe the objection to Ofra). Suppose we say ‘let n be an arbitrary number and let m be an arbitrary number’? If the reference facts are just brutely settled, they might be brutely settled so that ‘n’ and ‘m’ co-refer and they might not be. Either way, we can’t prove either that n is identical to m or that n is distinct from m, so we can’t ever conclude that arbitrary Fs a and b are identical (unless we can prove that there’s only one) or that they are distinct: and of course, that’s exactly as it should be. But the worry is that I can know that n=m because I know that ‘n’ and ‘m’ co-refer: they must both refer to the most natural number.

But once the rule isn’t restricted to the properties we can prove n has from the basis of facts we know about n but rather, as it has to be to deal with the reference problem, to the properties we can prove n has on the basis of facts that hold solely in virtue of n being a number, this problem dissolves. n is not identical to m, if it is, solely in virtue of being a number. It is in virtue of n being the particular number that it is, i.e. m, that it is identical to m. Likewise if n is in fact distinct from m, this is true in virtue of n being the particular number that it is - one other than m. With this restriction on the rule – and let me re-emphasise that any account that takes us to refer in cases of arbitrary reference must place some such restriction – I think there will be no unwelcome consequences to my approach. (At least, no additional unwelcome consequences over the brute facts view!) And the advantage is that, at the price of accepting these facts about naturalness, we avoid both brute semantic facts and the postulation of weird entities like the arbitrary number.

Ontological Cheating and Ockham's Razor

I’ve written a brief reply to Jonathan Tallant’s forthcoming Analysis paper, 'Ontological Cheats Might Just Prosper', that argues in favour of being the kind of ‘cheating’ presentist and actualist that simply takes truths concerning the past, or what could have been, to be ungrounded. Tallant argues that Ockham’s razor suggests we should be cheats, because if we can do without past or merely possible ontology, Ockham’s razor says we should. Don’t multiply entities beyond necessity, so since it’s possible not to believe in such things, you shouldn’t believe in them.

I argue that this has to be a bad understanding of Ockham’s razor: were it good, we should be Ontological Nihilists and believe that nothing exists. Since it’s possible to believe in nothing at all, believing in anything multiplies entities beyond what’s necessary, hence we shouldn’t believe in anything! Since we’re not Ontological Nihilists, we can’t be operating with this version of the razor.

Why aren’t we Ontological Nihilists? Because while it’s ontologically parsimonious, it’s ideologically extravagant. (See Jason’s paper.) Ockham’s razor has to allow that ontological parsimony needn’t be purchased if the cost is extravagant! But once we allow this, we’re just back to the old game of weighing up the admitted ontological benefits of cheating against what should be the admitted costs in its ideology and/or in its account of how truth depends on reality. The debate hasn’t progressed any.

I argue that every theory owes us an account of three things: what exists, what is true, and how truth links up to ontology. Ockham’s razor tells us, I suggest, that we shouldn’t accept a theory that postulates the existence of some things that don’t, according to its own view of how truth depends on ontology, do any work in accounting for what it itself says is true. That principle is going to tell us not to say, e.g., both that truths about the past are brute but yet there are nevertheless past entities. And that’s as it should be: that’s a bizarre combination of views to hold. But it’s never going to let us decide between two theories just by looking at their ontologies. And I think that’s as it should be: we have to look at the other two components as well, and see if the ontological advantage is being paid for at an appropriate price. And I can’t see any version of the razor that will mandate accepting the ‘cheating’ theories that won’t also mandate accepting Ontological Nihilism.

(I’ve also written a reply to a forthcoming paper by Stefano Predelli which argues against my view that there are no musical works. It’s here.)

Leeds metaphysicians sweep Oxford Studies in Metaphysics prize!

Some fantastic news for the Leeds metaphysicians: Jason Turner has won the the Younger Scholar Prize in Metaphysics, for his paper 'Ontological Nihilism'! This was after a record number of submissions. Well done Jason!

And the joint runners-up are Robbie Williams and Elizabeth Barnes for their paper 'A Theory of Metaphysical Indeterminacy' and me for my 'Truthmaking for Presentists'. So a clean sweep for Leeds!

These three papers will all be appearing in a forthcoming volume of Oxford Studies in Metaphysics.

Update: Jason's paper is now available on-line: check it out via the link above!

Further update: It looks like the above three papers will be published alongside Richard Woodward's earlier accepted paper 'Metaphysical Indeterminacy and Vague Existence'. So it looks like Leeds is really going to dominate that issue of OSM! Maybe it should be called 'Oxford Studies in Leeds Metaphysics'.

(Both Rich's and my paper make use of the way of thinking about metaphysical indeterminacy in the way Elizabeth and Robbie tell us to - so this journal will also see three papers defending the Elizabeth/Robbie plan. Metaphysical indeterminacy's day is here!)

New metaphysics blog

Just to announce a new group blog on metaphysics:
Matters of Substance. The idea is that this will be a forum for a whole bunch of metaphysicians, along the lines of PEA soup, Certain Doubts, The Garden of Forking Paths, etc. Robbie, Elizabeth and I will be showing up there, as will a bunch of other awesome metaphysicians, so add it to your bookmarks!

New Leeds philosopher

I'm delighted to announce that Heather Logue will be joining the department at Leeds in September. Heather is currently finishing up her PhD at MIT, and specialises in the philosophy of mind and epistemology, with interests in metaphysics, philosophy of science and feminist philosophy. She has published on disjunctivism, as well as co-editing an anthology of classic texts on that topic.

Since I arrived at Leeds (three and a half years ago), we've made 11 permanent appointments and 5 of them have been women. That's 45%. It's really nice to be in a department where that's true, and where it's true solely because we've pursued a policy of hiring the best person for the job.

Cameron on Merricks on Cameron on Merricks on Truthmakers

I've linked before to my contribution to a symposium on Trenton Merricks' book 'Truth and Ontology' (T&O). Merricks' reply (to me and my fellow symposiasts (?), Jonathan Schaffer and Scott Soames) can be found here. Obviously, in a symposium the author gets the final word. The good thing (and the bad thing) about a blog, though, is that there can always be another word! So here I'm going to respond to some of Merricks' replies to me.

A general style of argument that Merricks makes a few times in T&O runs as follows. If truthmaker theory is true then every truth has a truthmaker; the best candidates for truthmakers for the truths in domain D are the Xs; but we shouldn't believe in the Xs; therefore we shouldn't believe the truths in domain D have truthmakers; but we should believe they're true, therefore truthmaker theory is false.

Two instances of this argument schema plug in truths about the past and negative existentials for D and, respectively, Lucretian properties and totality facts in for the Xs. In my paper, I agree with Merricks that we shouldn't believe in Lucretian properties or totality facts, but I argue that the truthmaker theorist (even if she is a presentist) can do better in each case. Merricks argues that my candidate truthmakers shouldn't be believed in either. He also makes a te quoque against me, and argues that the reasons I give for not believing in Lucretian properties rule out my proposed truthmaker for negative existentials. I'll respond to these charges.

Let's take truths concerning the past first. Given the truth of presentism, what makes it true that I was once a child? The Lucretian says I have (presently) a purely past-directed property: the property of having once been a child. In 'Truthmaking for Presentists', I argued that what is peculiar about such properties is that an object's having them makes no difference to the intrinsic nature of the object at the time it instantiates it. We should only believe in a property F, I argued, if an object instantiating F at t makes a difference to how F is intrinsically at t. Lucretian properties don't make such a difference: they only make a difference to how the bearer was intrinsically – so we shouldn't believe in them. I argued that temporal distributional properties do better: an object's instantiating a temporal distributional property at t makes a difference to how the object is intrinsically at t (thus avoiding the charge of peculiarity facing the Lucretian) but it also makes a difference to how the object was intrinsically at the previous moments of its existence (thus solving the truthmaker problem).

Why might you not like this solution? Here's an inconsistent tetrad:

1) Presentism is true
2) Objects instantiate temporal distributional properties
3) If an entity instantiates a distributional property, it extends throughout the region across which that property distributes
4) If an object extends throughout a region of some dimension, the region of that dimension exists

From (2) and (3), objects extend through temporal regions. From (4) it follows that there are extended temporal regions, which contradicts (1), which entails that only a point of the temporal dimension exists.

Abandoning (1) or (2) would just be to reject my theory, so can either (3) or (4) plausibly be given up? In my contribution to the symposium, I suggested abandoning (4). I said the presentist has to abandon this anyway, since they believe in persisting objects, and these are objects which are extended throughout time, even though the regions of time throughout which they extend do not (according to the presentist) exist.

Merricks objects that "presentists should deny that existing at a time is anything like being located at a region . . . Similarly, presentists should deny that persistence is extension throughout a temporal region. . . So they should reject the view that persisting objects are extended throughout nonexistent regions."

The invocation of location at a (I presume spatial) region suggests that Merricks is thinking of my view as one where objects stretch throughout time just like they stretch throughout space, even though extended regions of time do not (unlike extended regions of space) exist. But certainly, I never urged the presentist to hold that view! The sense in which I claimed the presentist must hold that objects are extended throughout time is a trivial one: they must believe that there are objects which are not instantaneous existents – objects which do exist and either did or will exist at some past or future time. Call this extension through time. The presentist believes in the possibility of extension through time, in this sense, without extended regions of time existing. So in this sense of 'extension', (4) is definitely false, according to any sensible presentist. My point can basically be put as a challenge to those who see a tension between presentist and truthmaker theory: give me an argument that I should accept (3) for any sense of 'extension' stronger than this one. I grant (3) in this trivial sense of 'extension', but then (4) is obviously going to be denied by the presentist. And there are senses of 'extension' like the way an object extends through space which make (4) true, but then I don't see why I must accept the corresponding reading of (3). The burden of proof is on one who is pushing the inconsistent tetrad: tell me the sense of 'extension' you have in mind, and give me an argument as to why I should accept both (3) and (4) – until then, I'll continue to believe my account reconciles truthmaker theory with presentism.

Let's turn to negative existentials. Following this earlier paper, I argued that the truthmaker for claims of the form 'There are no Xs' is the world itself. The view is that each positive truth has a truthmaker, and that the world is essentially composed of all and only these truthmakers. Furthermore, the world is essentially maximal: it is necessarily a world, necessarily the largest thing there is – i.e. it is necessarily composed of all the truthmakers for the positive truths. So it can't be a proper part of any other thing. That means that, necessarily, the world can only exist if all and only the truthmakers for the positive truths are all and only the actual truthmakers for the positive truths. And so, since an actually true negative existential couldn't be false without some actually false proposition being a positive truth requiring a truthmaker, the world suffices as a truthmaker for all the true negative existentials.

Merricks objects to this proposal by objecting to the property of being a world. He says this is "a totality property, equivalent to being such that there is nothing more in the universe. So Cameron's world resembles the totality state by exemplifying a totality property essentially. . . Thus what Cameron calls 'the world' is nearly the same thing as the totality state." And hence I haven't really made any advance over Armstrong's totality states. And then there's the te quoque: the property being a world makes no difference to the intrinsic properties of its bearer at the time of instantiation, hence by my own lights (as seen above, RE Lucretianism) it's peculiar, and so my own principle tells us not to accept my own ontology. Ouch!

I think Merricks' objections here are misplaced. (In fairness, I should point out that he makes some others that I am not responding to here.) Merricks objects to the property of being a world. But I didn't appeal to any such property: I only appealed to the world!

I'm assuming the following kind of picture. The reason a truthmaker theorist admits properties into her ontology is to ground accidental predications. The reason we need to admit a property of being charged is to make true truths of the form 'X is charged' – but one only needs the property because X is merely accidentally charged: were X essentially charged, X itself would be an acceptable truthmaker for 'X is charged'. If every charged entity is essentially charged, we simply don't need to admit the property of being charged – the charged entities are ontology enough. It's only because the charged things might not have been charged that we need to admit the state of affairs of them being charged (which involves the existence of the property), to provide a necessitating truthmaker for the fact that they are charged.

There's only one thing that's a world, and it is essentially a world. So I deny that we need to admit a property of being a world. The world is ontology enough. That is why my view is perfectly compatible with the principle that mandates my rejection of Lucretian properties. It's also (one of the reasons) why I think I have an advantage over Armstrong's totality states view (for other reasons, see this paper): I am merely attributing a more robust essence (but in familiar ways) to an entity many of us already believe in – I am not introducing a peculiar property for the sole purpose of solving some truthmaker problem.

Finally, I'll say something about possibilism and modal truth. In T&O Merricks makes what seems to me a very odd claim: that admitting mere possibilia to ground truths concerning what might have been is no use, because both actualist and possibilist alike should, if they are to be truthmaker theorists, hold that what is actually true depends on what there actually is. Hence actual truths concerning what might have been must be grounded in actual ontology – and so admitting mere possibilia is no help to securing the truthmaker thought.

I see no reason why a possibilist who wants to be a truthmaker theorist should hold that actual truth depends on actual being. Actual truth is just truth, so this principle is just that truth depends on actual being. I think that should only be acceptable to a truthmaker theorist if they hold that actual being exhausts being simpliciter. The truthmaker thought, I think, is just that truth depends on ontology: and the truthmaker theorist should be able to appeal to whatever ontology they believe in, whether actual or merely possible, present or past, etc. The only reason for a truthmaker theorist not to appeal to the Xs to ground some truth is if they don’t believe in the Xs.

I made the following analogy to illustrate this. Would anyone think it a good demand that the truthmaker theorist ground truths concerning what goes on at other places only in ontology that exists here? I considered the proposition 'It's raining on the other side of the world', which is true in Australia. Should we demand that Armstrong account for this truth only by appealing to entities that are located in Australia? Surely not! Surely, Armstrong is at liberty to appeal to all the entities he believes in to ground this truth, no matter where in the world they happen to be located. Only a here-now-ist should believe that the only entities to be appealed to in truthmaking are ones that exist here.

Merricks objects to the analogy because he denies "that propositions are true at places". (He points out that were he an eternalist he would deny that propositions are true at times.) But I don't need to commit to propositions being true at places in any objectionable sense in order to make the analogy. My point is just that modal truths should be treated by the possibilist just like truths concerning what goes on at other places should be treated by all of us who deny here-now-ism. There's a perfectly good sense in which 'It's raining on the other side of the world' is true in Australia and not in the UK (given that it's raining in the UK, not raining in Australia, and that Australia is the other side of the world to the UK and vice-versa); there's a perfectly good sense in which 'Gordon Brown is now the Prime Minister of the UK' is true at the present time and not true 10 years ago; there's a perfectly good sense in which 'It's merely possible that there are talking donkeys' is true at this world and not at a world containing talking donkeys. Those are the pre-theoretic data; the philosophical work to be done is spelling out what this amounts to. I agree with what I take to be Merricks' thought: that what we should say in each case depends on what we think about the ontology of places, times and worlds, respectively. If you are a here-now-ist/presentist/actualist you should say that propositions are true at locations/times/worlds; if you are sensible/an eternalist/a possibilist you should say that the propositions expressed by these sentences at one location/time/world are different from the proposition expressed at a different location/time/world, and that the proposition expressed is true or false simpliciter, and not at a location/time/world. But the point remains: whatever we who deny here-now-ism say about my sentence, so should the possibilist say about modal claims. And so I can't see any more reason to insist that the possibilist appeal only to actual ontology in accounting for modal truths than I can see to insist that Armstrong only appeal to Australian ontology in accounting for my truth.

Anyways, Merricks' reply had loads of interesting stuff in it - these are just my initial thoughts about how best to respond.