Monday, March 23, 2009

Presentism, causation and truthmakers for the past

I’m working on both causation and the truthmaker objection to presentism, and it seems to me that it might be possible to kill two birds with one stone. What follows is the basic idea, and I’d love to hear your thoughts.

Suppose that presentism is true. What is the nature of causation? It’s the relation between what and what? Or, more relevantly, between when and when? Since, according to presentism, the past does not exist, either causation is a relation between nothing and something in the present, or causation is simultaneous, or causation is not a relation at all. The first option seems dubius. A two place relation (I’m ignoring contrastivism, for the moment) has two relata, after all, not one.

What, then, about the second option? C. B. Martin defends this view in The Mind in Nature—or, at any rate, that’s my understanding of what Martin defends. But it’s not clear how to make sense of causal processes on this view. (Persistence intuitively has causal constraints; how are we to make sense of these constraints if all causation is simultaneous?)

The third option seems to me the route to go. Here’s an initial proposal: Causation is a fact about presently existing (Armstrongian) states of affairs, or tropes if you have them. It is a fact about e, say, that c brought it about. Suppose, however, that existentialism is true, so that if x does not exist, there are no singular propositions about x. If c is a state of affairs and the particular that is a non-merelogical constitutent of c no longer exists, then the fact that c caused e is the fact about e that something c-like brought it about. If c is a trope no longer instantiated and the instantiation condition is true, so that uninstantiated properties do not exist, then too causation is the fact that something c-like brought about e.

How are we to understand “something c-like”? Here’s one proposal: Properties are or of necessity confer causal powers, so we can understand “something c-like” as “something with the following causal powers profile...” (Of course the Neo-Humeans can’t really accept this view, but how many Neo-Humeans are presentists?)

What should we say about the fact in question, that e was brought about by something c-like? It might be a property of the world, as in Bigelow’s “Presentism and Properties.” It might be a property of e. Or it might not be a property, but a fact grounded in something else. Or a primitive fact about e.

Whatever answer one gives here seems also to be an answer to the objection to presentism from truthmakers about the past. Hence the presentist, so long as they can offer a theory about the nature of the fact that e was brought about by something c-like, can kill two birds with one stone, a theory of causation and a response to the truthmaker objection.

Here’s an initial proposal. Take property instances to be tropes. Then, with certain other assumptions about tropes, events can be understood as tropes. So trope c caused trope e. That turns out to be a fact about e: that it was brought about by c. Since I’m inclined to accept both existentialism and the instantiation condition, this will turn out to be the fact, about e, that it was brought about by something c-like. The fact is a basic truth, and e alone is its truthmaker. This is analagous to e’s also being, in virtue of either being or of necessity conferring causal powers, (part of) the truthmaker for counterfactuals describing what objects with e would do in various circumstances. It is a truthmaker for future truths and for the past truth about c.

One further claim, and we have a theory of truthmakers for the past. These basic causal facts about tropes are cumulative. So the fact that e was brought about by c is the fact that e was brought about by something c-like which was brought about by something...., which was brought about by something..., and so on. As long as there is a causal chain from some present state of affairs to every past state of affairs, there is a present truthmaker for every past state of affairs.

Tropes carry with them their entire causal history and their entire power profile, and so are truthmakers for past and future truths. Present property instances do a lot of work on this view, but that’s about what we should have expected given presentism.


  1. I like what you say about causation, but I wonder about Truthmaker. What makes the truthmaker objection so intuitive is that it seems "Abraham Lincoln was assasinated" is made true by the same sort of thing as "I am sitting here writing a blog comment" But on your view it is differnt. Not only that, but it seems that the truthmakers of distant truths (The dinosaurs roam the earth) will be very different from more recent truths. If you go far enough back into the past,would not the causal trace of the past event be extremely, nay, vanishingly, faint?further you go back, the causal trace of the past event is going to vanish into near oblivion??

  2. Just quickly on option 2: it's my recollection that Brian Ellis defends somewhere the view that all causation is simultaneous, because all causation is interaction. After the interaction, the objects involved continue along the appropriate trajectories through spacetime until their next causal interaction. (It strikes me now that causal process theorists like Salmon and Dowe might defend a similar kind of view). What makes a process causal is that it is a trajectory produced by a causal interaction, or indeed is a collection of trajectories and causal interactions. Don't know how much I like the view—it seems to force ordinary event causation talk into a rather Procrustean bed—but it doesn't seem to have the problem that it cannot distinguish causal processes from others.

  3. The problem of causation by omission is the problem of how an omission can cause something (or how an omission can be caused, or maybe even how omissions can cause omissions if we wan to get really funky). Since omissions aren't things, we seem to have causation and hence the causal relation but without enough relata. So with respect to your option one, you might have a look at David Lewis's treatment of causation by omission in his "Void and Object" to see if any of the approaches he explores are useful.

  4. If all we want out of truthmaking is supervenience, then present tropes might be fine truthmakers for truths about the past. But, if what we want is something more like explanation, then present tropes won't do: present tropes don't explain why the past was the way it was.

  5. Gordon,

    I think the presentist has reason to deny that truthmakers for present truths and past truths are of the same sort. (See below for my response to Ben on this point.)

    You’re right that on the proposed view, if the causal traces of an object vanishe, then the present truths about it do to. That’s a problem with the view, unless one has reason to suppose that they couldn’t vanish. (Here’s *one* way they couldn’t vanish: God exists, and his beliefs are presently such that they were brought about by...)


    Thanks for the reference. I hadn’t intended to claim that Martin was the only one who thought causation is simultaneous. But I admit that I had forgotten about Ellis.

    I’m not sure, however, of the resultant account of a causal process. You say that what makes a process causal is that it is a trajectory *produced* by causal interaction, and production sure sounds causal to me. (I’ll see if I can prod Phil Dowe into commenting. I’m sure he’ll set me straight.)


    Thanks for the reference. I’ll post some thoughts after reading it (if I have any worth sharing).


    Thanks for the comment. I just read your forthcoming paper with David Sanson, “The way things were.” I liked it quite a bit. The first thing to say, then, is that I was not proposing that the tropes are properties like “was brought about by such-and-such.” Rather, I was proposing that ordinary properties like “is red” and “is thinking about presentism” are presently such that they were brought about by such-and-such. (And this being presently such that... does not have to be analyzed as the trope having the property of being such that...)

    Still, I agree with you that the present fact that my current property of thinking about presentism was brought about by my reading your paper is not an *explanation* of my reading your paper. I really liked how you brought that point out in the paper, especially against the abstract times theorists. But I’m not sure why any presentist would suppose that the *explanation* of past events are present (baring, of course, backward causal chains).

    Here’s how I imagine a presentist responding: There is nothing that presently exists that explains why I read your paper. Of course there *was* something that explains my reading your paper, and there is a presently existing thing that makes true that there was something that explains my reading your paper, but the presently existing thing that makes true that there was something that explains my reading your paper is not what explains my reading your paper.

    Explanations of past events are, barring backward causal chains, in the past. Truthmakers for propositions asserting the past existence of those explanations are present.

    I take it, given the comments at the end of your paper, that you agree with the first claim. But you deny the second? In the end, I’m not sure how to understand your positive proposal. (How does it differ from the way I imagined a presentist responding?)

  6. On the God thing. It would seem on that hypothesis the truthmaker of 'God knows X" and "X" are going to be the same. Even though the propositions are about different things. Of course ordinarily we have this with "The couch is colored" and "the couch is red" But this case is not analogous to that.

  7. Ben and Jonathan ~

    I think Jonathan's right about the presentist answer about explanation. Here is perhaps just a bit more detail.

    Jonathan read Ben's paper. That is, WAS(Jonathan is reading Ben's paper). Similarly, WAS(Jonathan thinks the paper looks good), WAS(Jonathan's got some extra time today), etc. Also, Jonathan thinks the paper looks good is true at t1, Jonathan has some extra time today is true at t2, Jonathan reads Ben's paper is true at t3, t1 is earlier than t2; t2 is earlier than t3. Perhaps build in some conditionals: If Jonathan thinks Ben's paper looks good and Jonathan has some extra time, then Jonathan will read Ben's paper. That's true at several times.

    The truthmakers of all these are present, in some way or other. I like the trope idea. I am curious, Jonathan, how you think it works for future truths.

  8. Gordon,

    I don't think the truthmakers for “God knows that X” and “X” will be the same.

    Suppose a truthmaker for WAS(X) is, as I proposed, the primitive fact about the state of affairs, _God’s believing that WAS(X)_, that it was brought about by whatever state of affairs was the truthmaker for X.

    That primitive fact about God’s current belief is not what makes it true that God presently believes that WAS(X). Doesn't that seem right?


    For present truths, I’m inclined to think of properties (whether tropes or universals) as powers or propensities in a robustly anti-Humean way. So the current distribution of those powers, together with their intrinsic nature (that is, what those powers are powers for), will suffice to make it true that WILL(X), when that’s true, or Probability(WILL(X))= x, when that’s true.

    I could say a lot more, but I think a Shoemaker/Heil/Martin/Mumford/Bird/Ellis type view of properties as powers will generate truthmakers for the future. Does that make sense?

  9. Jonathan:

    Thanks for the plug. You say, "Explanations of past events are, barring backward causal chains, in the past. Truthmakers for propositions asserting the past existence of those explanations are present." I think I agree with both claims -- if all we require of truthmaking is something like supervenience. The positive proposal isn't about truthmaking; it's about the need to appeal to the past. (David Sanson has a lot more to say about the positive proposal than I do. I'm more of a negative guy.) Providing a present truthmaker for a proposition that asserts the past existence of an explanation does not obviate the need to appeal to the past -- if you want to explain why that proposition is true. It's true in virtue of the past existence of the explanation, not the present existence of any truthmaker.

  10. Jonathan,

    Yes that makes sense, my brain (or soul!)misfired
    as I wrote that comment. Though it is interesting that on the traditional (to me, false) account, God's knowledge is never caused by anything in creation--it works the other way around. I still have a worry that these newfangled truthmakers are not really what the statements are about. If I am thinking about a past event, then that past event is the intentional object of my thought. But this is just a clash of intuitions, I think.

  11. Jonathan,

    As Ben says, there are two things you might want out of truthmakers for propositions about the past: supervenience or explanation. I have never understood why someone would want mere supervenience here without explanation, but that might be a failure of my imagination. So I'll assume you want truthmakers that do explanatory work of the right sort. But if not, I'm interested to know what the other motivations are for mere supervenience here.

    If you want explanation, then what, exactly, do you want an explanation of? You suggest that the explanation of why you read our paper is obviously past, but that the truthmaker of 'Jonathan read Ben and David's paper' is present. I take it that you mean that the causes of your reading our paper (your interest in the topic, etc.) are obviously past. Agreed. But then that suggests that the truthmaker must be doing some other explanatory work, right?

    So what explanatory work does a truthmaker do, and is it okay for that work to be done by present truthmaker?

    I take it a truthmaker-style explanation is an explanation that points to those features or aspects or constituents of reality that make a given proposition true. In our paper, Ben and I were trying to argue that no features or aspects or constituents of the present are plausible candidates for doing that explanatory work when it comes to propositions about the past.

    The positive proposal---which in the paper is, admittedly, half-baked---is, very roughly, to treat truthmaking in this case as a relation between a presently existing proposition and a no longer existing past state of affairs.

    The bigger picture strategy is to push the idea that, even as a presentist, you've got to appeal to the past, so that presentism should not be thought of as the project of attempting to find presently existing stuff to do all the work that past stuff appears to do. Instead it should be thought of as the project of attempting to explain how no longer existent past stuff can do all the work it does even though it no longer exists...

  12. Ben and David,

    Thanks for the comments.

    I agree that truthmaking is not merely supervenience. (In fact, I don’t think any metaphysical job is done by supervenience. It’s simply correlation, empty of any metaphysical import.)

    But I don’t think truthmaking has to be as strong a form of explanation as you suggest. There’s explanation and then there’s explanation. You seem to want responsibility or sourcehood in truthmakers. If that’s what’s wanted, then I agree that nothing present does that job for past truths. The only thing that does that job no longer exists.

    I’m not sure I can give an alternative account of the “in virtue of” relation I have in mind that is weaker than responsibility. Whatever it is, I imagine that it would be satisfied by anything that completes the following dialogue. “Is P true?” “Yes, after all, ...” Whatever is responsible for P would work, but not all supervenience bases would. I don’t have an argument for thinking that something short of responsibility but stronger than supervenience would work, but it seems to me that it could.

    On your positive proposal, I’m not sure a presentist should be happy with it. It involves a relation between the present and something that no longer exists. First, how can a relation relate something and nothing? Second, if it can relate something that presently exists and something that does not presently exist, then it looks like we can quantify over something that does not presently exist. Would a presentist be happy quantifying over non-presently-existing objects? I would have thought not.

    That’s why I said that it seems to me a presentist should just deny that there are present explanations (of the sort you ask for) of past truths. If *there are* such explanations, presentism is false. You might think that if there are no such explanations, then there are no truthmakers for present propositions about the past. (I actually don’t think that’s a crazy idea. I’m inclined to accept existentialism, after all, so I don’t think there are present truths about objects that don’t presently exist.) But it seems the most plausible response is to deny that truthmakers have to be explanations of that sort.

    So where did I go wrong?

  13. Jonathan:

    You went wrong in assuming that we were the sort of sane and sober non-Meinongian presentists who think that only objects that exist can stand in relations or be quantified over. (It's a pretty natural mistake to make!) On the Meinongian view, there are explanations (of the sort we ask for) of truths about the past -- it's just that they're in the past and hence don't exist.

    I think you and I and David can all agree that there are no present explanations (of the sort we ask for) of truths about the past. But here we diverge. You sensibly draw the conclusion that, as presentists, we should therefore stop looking for such explanations. We draw a different conclusion.

    I don't have sophisticated views about explanation, and I'm not sure I have a good grip on what "responsibility" is, but one of the points we made in the paper is that some of the things one might say to fill in the blank in your dialogue (A: "Is P true?" B: "Yes, after all ... ") might be present and might have some explanatory power -- e.g. Arnold now has the property of having been pale -- but their explanatory power comes from their connection to whatever it is about the past -- e.g. Arnold once had the property of being pale -- that packs the real explanatory punch.

  14. Oh—OH!

    I see.

    It's all falling in place! (I now feel roughly how I felt the first time I really understood Lewis's view of possible worlds.) Right, so now we're back to my post about proxy "presentism," and I've been delinquent in responding to comments there. I'm not sure *that* view deserves to be called presentist.

    Which, of course, doesn't mean it's false. It is ontologically serious; it has that much going for it. But I'll have to give it some time to really sink in in order to move past the incredulous stare.

  15. Fair enough. I would like to hear more about the kind of explanation you think the truthmakers are doing in this case, not in the sense of wanting to hear your developed theory of the "in virtue of" relation, but in the sense of wanting to get a sense of why we should be motivated to provide truthmakers that do the sort of work you describe.

    But let me step away from those issues, and make some comments about your original proposal. Forgive me if I recapitulate too much, but I'm trying to make sure I've got the view right.

    What you say about causation commits you to certain present facts, e.g., that e was brought about by something c-like. You then worry about the nature of that fact. I take it the problematic feature of that fact is whatever is going on metaphysically behind the 'was'. You suggest that this fact, however you account for it, is going to look a lot like the sorts of facts presentists use as truthmakers for propositions about the past.

    That seems right to me: if our response to the truthmaking problem is to posit presently existing facts described using a past tense, then those facts will be of a kind with the causal facts you are positing. So what we have here is a problem dear to my heart: how, as a presentist, to understand the metaphysics of the past tense.

    But then you move further, suggesting that all truthmakers for propositions about the past will be causal facts. This further move looks like it puts you in line with the tradition of presentists who claim that the truthmakers for claims about the past are presently existing causal traces. And that looks like it requires a variety of hefty assumptions. Most obviously, it leads to a strong form of determinism or truth value gaps, right? Less obviously, it requires that

    - all past truths supervene upon causal facts about the past

    This might be right but it isn't obviously right. It is something like the principle that if something isn't part of the causal story, then it isn't part of the story at all...

  16. David,

    Thanks, again, for the insightful comments. I do hope you (and Ben, too) saw that my last comment was mostly tongue-in-cheek!

    On explanation: I don't really have a theory. So why should we provide truthmakers that fall short of robust explanation? I suppose it won't do to say that, since presentism is true and there are no presently existing robust explanations of past events, there must be something short of robust explanations that, in some vague sense, ground present truths about the past. I suppose it also won't do to say that, since presentism is true and the Meinongian view if false, there must be something that presently exists short of robust explanations that, in some vague sense, ground present truths about the past. But failing that, I'm not sure exactly what to say. I'll give it some more thought.

    You've got the original proposal right. I'd be interested in getting references about the presentists who appeal to presently existing causal traces. (Alas, I don't know the presentism literature as well as I need to.)

    Regarding determinism or truth value gaps: I had always assumed the right position would be one where 1) a proposition like WILL(P) is either false or neither true nor false, and 2) Probability(WILL(P)) is non-zero. But I recently had an exchange with Alexander Pruss about this where he presented an on-the-face-of-it persuasive argument that one shouldn't hold both 1) and 2). So I'm not sure what to say. I'd welcome suggestions! (Or did you mean to suggest a problem about past truths, not future ones?)

    Finally, on supervenience: Yes, I think that's the right thing to say about my proposal. I agree it's not obviously right. I think that's what was at issue in the above exchange with Gordon. There I claimed that one way to solve this problem is to appeal to the existence of God. But leaving that aside, I'm not sure why one couldn't bite the bullet and say that, necessarily, if x exists, x leaves some causal trace. (Everything that is, does.)

  17. I'm not sure exactly about presentists who appeal to presently existing causal traces. But in _Four-Dimensionalism_ (on p. 38 and p. 38 n. 21) Sider cites Lukasiewicz from 1967, Dummett from 1969, and Wright from 1987 as holding (or being sympathetic to) verificationist views about the past.

  18. One might ask, how present is the present? The immediacy of consciousness is the present. As fast as it takes to flick on a light switch, it is done and gone. Memory takes up the slack. Any present instantiation of conscious thought is automatically put into memory and drawn upon to extend ongoing present flickers of momentary conscious thoughts of actual reality, smoothing out the moment by moment flickers of conscious thought of actual reality.

    The present is, in short, a memory mapping of actual reality, a cumulative,linear rendering of instantaneous events of consciousness. In other words, the present is the past more than it is the actual present. As present as can be the immediacy of an instantaneous event to our conscious minds is thus the present; and likely unavailable to conscious scrutiny, since it is memory, the past, that is available to us, for the pixelation of conscious events are more instantly available in the neurology of the mind than it is in the instantaneous moments of actual reality.

    Presentism is a questionable philosophy.

    I am looking for a real-time philosophy club in Winnipeg, maybe here at Starbucks.