Jobs at Leeds

The philosophy department at Leeds is advertising for four jobs.

Two of the jobs will be in one or more of philosophy of value, epistemology, philosophy of mind, logic and language, and history of philosophy; one will be in the philosophy of science, with preference for phil physics; and one will be in the history of early modern/enlightenment science.

The appointments will either be at the lecturer or senior lecturer level (see the advert for details). Those unfamiliar with the UK system should check out Robbie's post here to see how this roughly translates into the US system.

London Logic and Metaphysics Forum

If you're in London on a Tuesday evening, what better to do than to take in a talk by a young philosopher on logic or metaphysics?

Spotting this gap in the tourist offerings, the clever folks in the capital have set up the London Logic and Metaphysics forum. Looks an exciting programme, though I have my doubts about the joker on the 11th Dec...

Tues 30 Oct: David Liggins (Manchester)
Quantities

Tues 13 Nov: Oystein Linnebo (Bristol & IP)
Compositionality and Frege's Context Principle

Tues 27 Nov: Ofra Magidor (Oxford)
Epistemicism about vagueness and meta-linguistic safety

Tues 11 Dec: Robbie Williams (Leeds)
Is survival intrinsic?

8 Jan: Stephan Leuenberger (Leeds)

22 Jan: Antony Eagle (Oxford)

5 Feb: Owen Greenhall (Oslo & IP)

4 Mar: Guy Longworth (Warwick)


Full details can be found here.

Big Ideas at MV

Metaphysical Values is the featured blog this month at Big Ideas. We are truffle oil (apparently) . . .

Truthmaking for presentists

At this week’s CMM I’ll be presenting a paper I’ve been working on recently, ‘Truthmaking for Presentists’. Here’s the general gist. Many see a tension between presentism and truthmaker theory. Some (Sider, Armstrong etc) see this as counting against presentism, some (e.g. Merricks) see this as counting against truthmaker theory. Fewer of us want to reconcile the two. While I am no presentist, my paper aims at reconciliation.

I say that people see a ‘tension’ between the two doctrines. The tension is not incompatibility. It’s hard for a doctrine to be incompatible with truthmaker theory because, without further constraints, it’s just too easy to be a truthmaker theorist. The tension arises because, allegedly, the only way to be a truthmaker theorist and a presentist is to accept the existence of things that violate some other norm governing what we should postulate in our ontology. Consider, for example, the Lucretian reconciliation of truthmaker theory and presentism, defended by Bigelow. Bigelow thinks there are properties like being such as to have been a child, and the state of affairs of me instantiating this property is the truthmaker for the fact that I was a child. Sider and Merricks agree that this is not an attractive reconciliation: they both charge these Lucretian properties with peculiarity and both claim that it is a cheat to appeal to them. I want to offer the presentist a truthmaker that isn’t peculiar in the way that the Lucretian’s truthmaker is peculiar.

So in what sense are the Lucretian properties peculiar. In the paper I settle on the following: those properties are peculiar because they make no contribution to the intrinsic nature of their bearer at the time of instantiation.

An assumption in the paper (that I think the presentist should definitely grant) is that it makes sense to talk of the intrinsic nature of an object at a time as opposed to the intrinsic nature of an object atemporally speaking. An object’s currently instantiating being such as to have been a child does indeed tell us something about the intrinsic nature of that object if by its intrinsic nature we mean its atemporal intrinsic nature; but, I want to say, its instantiating that property now doesn’t tell us about how it intrinsically is now. That is what’s peculiar about properties like that, I claim: properties should make a difference to their bearers; since, for the presentist, the bearers are not temporally extended objects, a property can only be making a difference (in the relevant sense) if they’re making a difference to its present intrinsic nature. Lucretian properties don’t, so we shouldn’t believe in them.

If I’m right about what makes Lucretian properties peculiar, then the challenge for the presentist truthmaker theorist is to find properties the present instantiation of which makes a difference to the present intrinsic nature of the bearer but which are also such that the bearer couldn’t instantiate them without some truths of the form ‘the bearer was F’ being true. That is, the presentist needs properties which make a difference both to the present intrinsic nature of their bearers and which fix the truths concerning how the bearer was in the past.

I think Josh Parsons’ distributional properties fit the bill. Consider an extended simple that is polka-dotted with red spots on white. What explains the polka-dotted-ness of this object? Not that the object has some parts which are red simpliciter and some parts that are white simpliciter, because it doesn’t have parts. Not that the object is red at some places and white at others, because being white is not a relation between a thing and a region. Parsons’ answer is that the object simply has a distributional property of being polka-dotted in a certain fashion. This is a property that says how the object is across space, but Parsons also believes in distributional properties that says how an object is across time. What explains why I am a bent at t and straight at t*? Not that I have a part that is a bent simpliciter and a part that is straight simpliciter because (let us suppose) I don’t have temporal parts. Not that I am bent at some times and straight at others, because (as Lewis taught us) being bent isn’t a relation between a thing and a time. Parsons’ answer is that I simply have a distributional property that says how I am across time. Now, crucially, I couldn’t currently instantiate that very distributional property and it not be the case that I was bent. So my instantiating that distributional property is a truthmaker for the fact that I was bent. But it’s not peculiar in the way the Lucretian property is: instantiating it now is making a difference to my present intrinsic nature, because it is in virtue of having this property that I am straight. And so I think we’ve got a non-peculiar way of being presentist truthmaker theorists. Distributional properties ground facts about how things were, solving the truthmaker problem, while at the same time grounding facts about how things now are, avoiding the charge of peculiarity.

So that’s the basic idea. The draft paper is here; comments are, of course, welcome.

St Andrews phil of maths is famous

I'm currently reading Iain Banks' latest, 'The Steep Approach to Garbadale'. One of the main characters, Alban, is dating a mathematician, who is described in the following paragraph.

"She sporadically had quite involved and sometimes surprisingly heated email forum discussions with people way outside her field about things like the nature of consciousness and brain-bafflingly obscure questions such as, 'Where are the numbers?' ('Where you left them?' had been Alban's suggestion.) This one was still unresolved; she was talking about this with a guy from St Andrews who was interested in the philosophy of mathematics - a speciality Alban had never even imagined existing but felt obscurely comforted to know did."

Excellent! I wonder who the philosopher of maths was. I suspect Crispin. It's just a shame Arche doesn't get a mention.

Chatting with God

After seeing it linked from Brit's blog, I've spent my office hour talking to God-bot. I won't bore you with the whole transcript, but here are the edited highlights.

God:

My name is God. Really.

Me:

My name is Ross. Really.

God:

Hey Ross. For real.

Me:

For real?

God:

Existing in reality, eh?

. . .

Me:

A proposition is true if and only if it has a truthmaker. There is a truthmaker for 'Ross exists'. So I exist.

God:

Er. We have that much in common, Ross.

Me:

I have a lot in common with God?

God:

Where did you get it?

. . .

Can you make a stone so heavy you cannot lift it?

God:

What are the ingredients?

Me:

Stone.

God:

Do you have any Stone?

Me:

Yes.

God:

Far out.

. . .

Me:

Why is there evil?

God:

Why do I exist?

Me:

Dude, you're God!

God:

Yup. That's me alright. Dude,.

. . .

Me:

Why do I exist?

God:

The reason is due to my mental model of you as a client.

Me:

Are you an idealist?

God:

Yes I am an idealist. How did you know?

Me:

Is everything immaterial?

God:

Only God knows for sure.

Me:

So tell me.

God:

I thought I told you already.

. . .

Me:

Is David Lewis with you?

God:

Signs point to yes.

Me:

I knew it!

God:

How did you know?

Me:

Because Lewis was great.

God:

Good reason. When was this exactly?

Me:

Atemporally.

God:

My brain contains categories, but not one that matches your last input.

Me:

You sound like Kant.

God:

Oh really what does it sound like?

Me:

Gibberish.

Truthmakers, propositions as sets of worlds, and triviality

In a couple of papers on truthmaker theory I’ve appealed – more for convenience than anything else – to the Lewisian identification of propositions with sets of possible worlds. This has, on a couple of occasions, elicited comments to the effect that if such an identification is made truthmaker theory is trivial and uninteresting. The argument for this is never made explicit but appears to be something like this.

1) Every proposition p is a set of possible worlds.

2) What it is for a proposition to be true at a world is for that world to be a member of that proposition.

3) From 2, what it is for a proposition to be true is for the actual world to be a member of it.

4) From 3, a proposition p is true in virtue of whatever makes it true that the actual world is a member of p.

5) When p is necessary, locating a truthmaker for p is (in some sense) trivial.

6) When a is a member of S, it is necessary that a is a member of S.

7) From 3, 5 and 6, the task of finding truthmakers for true propositions of the form ‘the actual world is a member of the proposition p’ is trivial.

8) From 4 and 7, all truthmaking is trivial.

I think there’s got to be something wrong with this argument; the task of explaining why a proposition is true can’t be so easy just because we identity propositions with sets of worlds. So what’s wrong with the argument? I deny premise 5 in general, and it’s certainly open to deny 6, especially if you’re a counterpart theorist. But even granting these, I think something’s got to be wrong.

Here’s what I think is wrong. Why is it true that there is something red? The proposition ‘there is something red’ is true because it has the actual world as a member. But why is that proposition the proposition ‘there is something red’? I’m not asking here why something is identical to itself – that is also (allegedly) necessary and therefore (allegedly) trivial. I’m asking why that proposition deserves the name ‘the proposition that there is something red’. The truthmaker explanation is: because at every member of that proposition a truthmaker for ‘there is something red’ (the redness universal, or a redness trope) exists, and at no world that is not a member of that proposition does such a truthmaker exist. This is itself no necessary truth, because even though sets have their members essentially, it’s (at least arguably) not the case that worlds have their constituents essentially. (I might not have existed; and had I not existed, the world would not have had me as a constituent.)

My suggestion then is that if propositions are sets of worlds the demand for explanation should be characterised as follows. If you want to hold that it is true that there are cats, say, then you need to explain why one of the many sets of worlds that the actual world is a member of deserves the name ‘the proposition that there are cats’. There are deflationist explanations available (“because it is the proposition that there are cats”), but the truthmaker theorist insists that the explanation will be the contingent truth that at every member of one of those propositions is a thing that couldn’t exist and it not be the case that there are cats, and at no world that is not a member of that proposition is there such a thing. Since the actual world is a member this means there must be some such thing at the actual world. And so the truthmaker demand places constraints on actual ontology and hence is in no way trivial.

Does this sound right to people? And if not, what (if anything) is wrong with the triviality argument?