Wednesday, October 24, 2007

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.


Ian said...

Hi Ross, I have some serious misgivings about this proposed fix. It only makes sense, it seems to me at least, to say that some object has the distributional property of being polka-dotted, say, if there is some region of space (filled by the object) over which it varies. If there is no such region, then the object cannot be polka-dotted. And if the object is only point-sized, it cannot be polka-dotted either. To have a distributional property, in other words, it seems we need there to be some extended area filled by the property-bearer over which the property is "distributed" (I'm not sure if that's the right terminology, but hopefully that's clear).

So in the case of presentism, I don't see how we could get objects to have temporal distributional properties without already having other times. But then it's difficult for the presentist to accept other times without ceasing to be a presentist. After all, on presentism, there's no time but the present. They could, of course, go with ersatz times but then it seems all the heavylifting with regard to truthmaking is going to come from whatever they think is playing the role of ersatz times, not from the distributional properties. So either way, this doesn't seem a very promising route to me.

Ross Cameron said...

Hi Ian,

Thanks for the comments. I don't see any reason to think that in order for something to have a distributional property that says how it is across a region then the region itself has to exist. I would, for example, be just as happy for the here-now-ist to admit the existence of polka-dotted extended simples as I am for the presentist to adopt my proposal.

I admit there's something to the contrary intuition. But I don't admit that it "doesn't make sense" to say what I am saying. The presentist, as I understand it, is in the habit of taking a Parmenedian slice of the eternalists universe and claiming that that is all there is. Take a Parmenedian slice of Parsons' universe and you get things instantiating distributional properties without getting the regions that those distributional properties distribute over. You might intuitively dislike such a possibility, but I can't see why it is meaningless. And as for the intuition: I admit to sharing it to an extent. I just don't think that counts for much at all.

Ross Cameron said...

Here's another point. The presentist doesn't think I am an instantaneous object. There is a sense in which they admit that I am extended in time. Suppose someone objects to the presentist by saying that you can't believe in something that is extended in time without believing in the region of time throughout which it is extended. That doesn't seem like it will move the presentist. The presentist is precisely rejecting the thought that to believe in entities with temporal duration you need to believe in the region of time through which they have that duration. If we think that's not allowed then presentist isn't even a runner in the first place. But if it is allowed, then why shouldn't we be allowed to believe in distributional properties without believing in the regions over which they distribute? I see the cases as exactly analogous. If the presentist can take a Parmenidean slice of the world at the present time and still believe in me, despite the fact that I am not an instantaneous entity, then she should be allowed to take a Parmenidean slice of the world at the present time and still believe in the distributional properties, despite the fact that they distribute over time.

Mike said...

So in what sense are the Lucretian properties peculiar.

I thought their peculiarity (or what explains why they involve cheating) wrt truth-makers was that the properties were non-reductively tensed? There is no fact, no "categorical fact" (I think Sider says), in virtue of which it is true that I was once a child. There is just the cheating "fact" that I simply have that property. Molinists do the same thing with counterfactuals of freedom. They're true in virtue of their being counterfactual facts.

Ian said...

"Take a Parmenedian slice of Parsons' universe and you get things instantiating distributional properties without getting the regions that those distributional properties distribute over."

But that's exactly what I'm having trouble with. I don't see how taking a single slice of Parson's universe could preserve the distributional properties since you've basically taken away the whole distribution. After all, it's not like in an eternalist version of Parson's universe that a temporally distributional property is a property that an object has intrinsic to each instant of the temporal period which the distributional property "distributes over". Or, at least, it wouldn't seem so to me. Having such a distributional property at a particular time sure seems extrinsic to that time to me. But then, if we start chopping off bits of the universe until we only have a single slice left, we've effectively gotten rid of the distributional property. I'm not sure that really captures my gut feeling about this, but that's another rough pass at what it might be.

Ross Cameron said...

Hi Mike,
Yes, Sider points to the lack of categoricity. But he admits that that is a pretty elusive notion. So part of what I'm aiming to do is to locate the peculiarity in something less elusive.

I understand the concern; as I said, I share the intuition to an extent. I just don't think we should place much weight on such intuitions. I do think of the things in Parsons' eternalist universe as instantiating the distributional property at each instant. At the very least, I don't see anything incoherent in stipulating that to be the case. In which case believing in just what exists at one instant of that world entails believing in the property that distributes across time without believing in the region of time. You can argue that such worlds are impossible if you want, but I see no reason to think they're incoherent.

Mike said...

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.

But what makes it true now that I am not bent or straight is not the distributional property you describe, is it? Why wouldn't it be just the non-distributional property I now have of not being bent? The distributional property does not seem to be doing any of the work that makes it true that I am not bent now. Or do you want to say not only that I have the distributional property, I don't have the non-distributional one?

This might be just a reformlation of Ian's worry, I don't know. A short argument: If a simple X presently instantiates a temporally distributed property P then X now is temporally extended (into the past). But, if presentism is true, then X now is not temporally extended into the past. So X does not presently instantiate P. What am I missing? I agree that if X does presently instantiate P, then you seem to have the right sort of truthmaker there.

Ross Cameron said...

Hi Mike,

I do think the dist prop is doing the truthmaking work in making you not bent or straight now. Once you've got the dist props, you don't need non-dist ones.

The 2nd argument does look to me like Ian's worry. I think there's an equivocation. You say

"If a simple X presently instantiates a temporally distributed property P then X now is temporally extended (into the past). But, if presentism is true, then X now is not temporally extended into the past"

I think there's a sense of 'temporally extended' in which things are temporally extended even if presentism is true. And it's this sense in which a thing needs to be temporally extended in order to instantiate a temporal dist prop. There's also a sense in which things aren't temporally extended in presentism is true, but I don't see why a thing needs to be temporally extended in this sense to instantiate a temp dist prop. (I say more about this in the actual paper.)

Mike said...

Thanks Ross. I'll look for the details in the paper. On the non-distributional properties, I agree that you won't need a non-distributional P if you have a distributional P. You probably address this, but wouldn't you then have have the non-distributional ~P? If not, you'll need some argument for why there just are no non-distributional properties. Right now it seems strange that there wouldn't be any. But I'll think about it.

Ian said...

One more try at what's bothering me and then I'll (hopefully) stop (though, by the way, I'm not sure why the bare intuition that an extended region is required for a distributional property doesn't "count for much" - but, oh well):

First, let's take an example. Say only a single point in space-time exists and a single object exists at that point. And let's say facts about other spaces and times are grounded in facts about the distributional properties of the object at this point. Now let's add to this object the property of being polka-dotted with green and purple spots in a particular way. So is it green or purple at this single point (assume, for the moment, color realism and that points in a uniformly colored region will themselves have that same color)? That is, in virtue of what would this point fall under one "differentiation" (for lack of a better word) of the distribution rather than another? And even if we did narrow down the color, is it a point near the spatial end of the object or somewhere in the middle? I don't see how the distributional property - which all by itself is supposed to provide the truthmaker for such things - is going to decide that. So it looks like there's a real problem here and hopefully it's obvious how this same problem will also apply to the presentist. That may be a rather different trouble from what I expressed earlier, but it's from the same general constellation of worry that's been swirling about in my head.

Ian said...

Okay, I promised I wouldn't try again, but I forgot to put this in my last post (honest!):

Take two properties, F and G. In situation s1, object x has F and in s2 it has G instead. In each cases, x has the particular intrinsic nature it has in virtue of having F and in virtue of having G, respectively. Suppose now that there are certain sentences (one set in s1 and a another one in s2 which is inconsistent with the former) which are NOT true purely in virtue of x having F or G but are still true and about x (and nothing else). What exactly is the difference between F and G in virtue of which, say, 'p' is true in s1 but '~p' is true in s2? It's not enough just to say that one makes 'p' true and the other makes '~p' true since that's precisely what we're worrying about. To tie this into my last post, the matter becomes even more troublesom if it turns out that F and G are really just the same property.

Now let's say it just so happens that 'p' and '~p' have a particular grammatical structure called 'being past-tensed'. Hopefully you can see where this is going. In virtue of making some of these 'tensed' sentences true and others false, some theorists decide to call these properties 'distributional' since they make sentences true in an interesting pattern similar to the way that spatially distributional properties tend to produce interesting patterns of true sentences. But then there's still that little lingering problem of how precisely these properties like F and G do the work of making some of these interesting sentences true and some false rather than vice versa.

JIW said...

Dear Ross
This is peripheral to your central point, but I am not sure, by the way, that Bigelow is right about what Lucretius in fact claims. I try to set out the evidence and weigh up the options in my:
“Epicureans and the present past” in Phronesis 51: 362-87

James Warren