Metaphysical universism

Here’s a metaphysical view I haven’t seen: the fundamental obejcts (priority version) or the only objects (existence version) are universes, but there can be more than one of these. Call this metaphysical universism (as distinguished from Quisling’s philosophy).

If in fact there is only one universe, metaphysical universism extensionally coincides with monism. But even in that case, metaphysical universism is a different theory, because it has different modal implications. And if we live in a multiverse, metaphysical universism is extensionally different from monism, since monism says that the one fundamental (priority) or one and only (existence) entity is the multiverse as a whole, not the universes.

I can think of two main advantages of metaphysical universism over monism.

First, suppose there is only one universe. It is plausible that there could be another in addition to this one. Metaphysical universism embraces this possibility. Monism only says that The One could have been bigger so as to comprise two spatiotemporally disconnected regions.

Second, there is an old intuition that being and unity are connected. In a multiverse, monism violates this intuition, for in a multiverse it is the universes that have unity, not the multiverse. Indeed quantum entanglement arguments for monism in the context of a non-Everettian multiverse seem to me to point more towards metaphysical universism than monism.

On the other hand, monism has a significant advantage over metaphysical universism insofar as monism solves the problem of truthmakers of negative and universal claims by making The One be the truthmaker of all of them.

Of course, both theories are false.

Accidents and truthmakers

It is difficult to hold (a) Aquinas’ idea that in transubstantiation the accidents of bread and wine continue existing after the bread and wine have perished together with (b) the idea that accidents are truthmakers for predications.

For if the accident of the whiteness of the bread is a truthmaker for the proposition that the bread is white, then it is (absurdly) true to say that the bread is white even after transubstantiation, since when the truthmaker exists, the proposition it makes true is true.

So, if one wants to hold on to the logical possibility that accidents could outlast their substance, one has to modify the thesis that accidents are truthmakers for predications. Instead, perhaps, one could say that the truthmaker for the proposition that x is F is x’s Fness together with x. This solves the problem of the bread being white after transubstantiation, since after transubstantiation there is no bread, and so if the truthmaker is the accident of whiteness together with the bread, then after transubstantiation the bread part of the truthmaker doesn’t exist. So all is well.

But here is a further puzzle. Intuitively, if God can detach the bread’s accidents from the bread when the bread ceases to exist, why can’t God detach the bread’s accidents from the bread while the bread continues to exist? But if God could detach the bread’s accidents from the bread while the bread continued to exist, then God could detach, say, the whiteness W of a bread from a bread B, and then the bread could be dyed black. Were that possible, it couldn’t be true that W and B are a truthmaker for the proposition that the bread is white, since W and B could continue to exist without the bread being white any more.

So, holding that the substance and its accident is a truthmaker for the predication, while accepting the logical possibility of Aquinas-style transubstantiation, requires one to hold that God can only detach the bread’s accidents from the bread while annihilating the bread. That seems counterintuitive.

Another move is this. Posit an “attachment” trope. Thus, when x is F, there are three particular things: x, x’s accident of Fness, and an attachment trope between x and x’s accident of Fness. Further, posit that in transubstantiation the ordinary accidents continue to exist, but the attachment tropes perish. And now we can say that the truthmaker of “The bread is white” is B, W and the attachment trope between B and W. (There is no infinite regress, since we can suppose that the attachment trope cannot exist detached.) But God can make W exist without the attachment trope, and either with or without B.

But it is an unpleasant thing that the attachment trope is a metaphysical ingredient posited solely to save transubstantiation. Moreover, the attachment trope would be a counterexample to the Thomistic principle that God can supply whatever creatures do. For it is essential to the story that the attachment trope cannot possibly exist in the absence of bread.

Probably, the Thomist’s best move is to deny that accidents (whether with or without the underlying substance) provide truthmakers for predications. If we did that, then a nice bonus is that we can have accidents moving between substances, which would provide a nice metaphysical account of why it is that flamingos turn pink after eating pink stuff.

Do all positive truths have truthmakers?

Consider this thesis:

1. Every positive true proposition has a truthmaker.

This seems plausible. But I think it is only reasonable to accept (1) if one accepts:

2. Any plurality of objects has a mereological sum or fusion which essentially has the members of the plurality as parts.

To see this, consider some plurality, the xs of existing things. Then, surely:

3. The proposition, E!xx, that the xs exist is positive.

But what object is suited to be the truthmaker of E!xx? The truthmaker of E!xx will have to be some object o with the property that, necessarily, if o exists, so do all the xs. Our best candidate for that object is some object that has all the xs as essential parts. But we also don’t want to include irrelevancies in the truthmaker, so we shouldn’t include in o anything that overlaps none of the xs. In other words, o will very plausibly be the mereological sum of the xs.

Since I don’t believe in fusions, I have to deny (1). But at least I may be able to accept:

4. Every positive true proposition has a plural truthmaker,

where a plural truthmaker of p is a plurality of objects that collectively make p true. Note that pluralities need not in general be objects themselves, so we do not have the same problem as above.

Uncontroversial examples of truthmaking?

I used to think that the following would be an uncontroversial example of truthmaking:

1. Any elephant is a truthmaker for the proposition that there are elephants.

But that’s only true if every elephant is essentially an elephant, i.e., couldn’t exist without being an elephant. For if x is a truthmaker for p, then x’s existence has to entail p. If Jumbo were accidentally an elephant, then Jumbo’s existence wouldn’t entail that there are elephants.

Given that essentialism is controversial, it seems that if we are to give uncontroversial examples of truthmaking, they have to be something like;

2. Jumbo is a truthmaker for the proposition that Jumbo exists.

3. Alice is a truthmaker for the proposition that at least one of Alice, Bob and Carl exists.

God is not a proper part

Nothing is greater than God in any sense. But a whole is greater at least in some sense than a proper part. Therefore:

1. God is not a proper part of any whole.

This has at least three interesting consequences:

2. Unrestricted compositionality is false.
3. Some true propositions have no truthmaker.
4. At least some de re propositions do not contain the object that they are about as a part.

That (2) follows from (1) is obvious: if (1) is true, then there is no object that has both God and the CN Tower as parts.
That (3) follows is pretty easy, too. Consider the true proposition that God created elephants (or that God exists and elephants exist). If this has a truthmaker, that truthmaker contains God as a part. But that truthmaker cannot just be God, since if x is a truthmaker for p, then that x exists entails that p is true, while that God exists does not entail that God created elephants. So, the truthmaker would have to contain God as a proper part, which would violate (1). The argument leaves open the possibility that all true propositions are made true by one or more entities, so that the proposition that God created elephants might be made true by God and elephants (not considered as a composite object, but simply as a plurality). But it's still the case that the proposition lacks a truthmaker.
Finally, (4) follows from the observation that there are de re propositions about God, such as that God has created us.

Divine simplicity and theistic reductive accounts

Some theists give reductive accounts of such phenomena as morality and proper function in ways that involve contingent divine mental states. For instance, one might say that the proper function of x is to A if and only if God designed x to A, or that we ought to A if and only if God wills for us to A. Such reductive accounts are apt, however, to be in tension with divine simplicity.

Here is why. If divine simplicity is true, then God has no contingent purely intrinsic features. One way to argue for this claim is that if divine simplicity is true, then God is the truthmaker for all claims purely about God (this is the Oppy account of divine simplicity, further developed by Jeff Brower and myself). Thus if God has a purely intrinisic feature F, then God is the truthmaker of the claim that God has F, and hence the existence of God entails that God has F, and hence God has F essentially. Another way is with the intuitive argument that if God has a feature (think of it as trope-like rather than as universal-like) F and F is accidental, then F cannot be identical with God's essence (since F and the essence have different modal properties—the essence exists in all world where God exists while F doesn't). But that is contrary to divine simplicity.

Now, plausibly, if two worlds do not differ with respect to the purely intrinsic features of x, but the worlds do in fact differ, then they must differ with respect to something extrinsic to x. Therefore, if God has no contingent purely intrinsic features, and God exists necessarily, then any two worlds that differ, must differ in respect of something extrinsic to God. Thus, all contingent facts supervene on created reality, i.e., on that which is extrinsic to God.

In particular, this means that there cannot be two worlds where the same created stuff exists, and the only differences are in God's intrinisc mental states. In fact, it is impossible for there to be intrinsic contingent mental states in God.

This does not destroy the possibility of the theistic reductionist accounts of proper function and morality. But it does mean that these accounts cannot make the contingent divine mental states be independent of what is, in fact, in creation. On the contrary, these mental states have to supervene modally on creation. But if so, then there are certain features of creation such that, necessarily, x has function F or y ought to A if and only if these features obtain. And if there are such features, why not analyze the function or the ought directly in terms of these features?

(This does not mean that God is left out. For these features are in creation, and God's creative and concurrent causality is involved in them.)

Augustine on evil

The problem of evil that Augustine struggled with so mightily was neither the inductive problem of evil that so exercises contemporary philosophers of religion nor the deductive argument from evil that the ancients worried about. Augustine's problem of evil was a metaphysical paradox generated by four plausible claims:

1. Evil exists.
2. Everything that exists is God or created by God.
3. God has not created evil.
4. God is not evil.

Unlike the ancient and modern problems, this isn't a deductive argument against the existence of God. Nor was Augustine, as far as I can tell, ever drawn to a fully atheistic solution. The Manichean solution was to revise (2) to say that everything that exists is a God or created by a God, and to similarly modify (3) and (4): there is a God who has not created evil and there is a God who is not evil.

Augustine's famous solution was to deny (1). Evil is but a privation of good. Granted, this does not mean that evil is a lack of good, but a lack of a due good. Hence, a claim that some evil has occurred is ontologically reduces to a claim of the form: (a) a good g does not exist, but (b) g is due. To my knowledge, Augustine does not say quite enough about what grounds (b), but what grounds (b) is not the evil in question, since (b) hold even if g existed. Claim (a) is true not in virtue of a truthmaker but in virtue of there not being a falsemaker. To make all this go, we need to also say something about what "g" stands for—presumably, a definite description of some good.

Augustine in his solution was not addressing either the deductive or the inductive problem of evil. That he was not addressing the inductive problem is obvious. That he was not addressing the deductive problem is also clear from the fact that a crucial premise in the deductive problem of evil, viz., that God is omnipotent, is not present. We need not, thus, think that Augustine's solution tells us anything very helpful with regard to these two problems. However, the fact that it was this problem that Augustine found difficult, and not the deductive or inductive, may be significant. Why was he unmoved by the arguments from evil? He does, of course, address these arguments, but it is not a matter for existential struggle. His response is basically that if we do black deeds, God will use us to paint the mustache in the cosmic painting that he is painting. It is a kind of sceptical theist move, based on the fact that we are in no position to see the whole picture.

Entailment Thesis for truthmakers

The Entailment Thesis for truthmakers is that

1. If x makes p true and p entails q, then x makes q true.

Mulligan et al. have the thesis, but it is surely false. For consider the following very plausible claim:

2. If x is a fundamental entity—one such that facts about its existence do not reduce to facts about more fundamental entities—then x is a truthmaker for the proposition, p, that x exists, and every truthmaker of p is either identical with x or contains x as a part.

Now, let N be a fundamental necessary being, e.g., God, or maybe the empty set. Plausibly, N is not a part of Fred the electron. Now: let p be the proposition that Fred exists, and let q be the proposition that N exists. Then, by (2), Fred is a truthmaker for p, p entails q, but Fred is not a truthmaker for q.

Truthmakers

It is fairly standard to say that the truthmaker of a proposition p is what makes p be true. But suppose we accept a non-deflationary theory of truth on which the claim that p is true is distinct from the claim that p, and is the attribution of the property of truth to p. Now let p be the proposition that there are horses. Then, any horse (or maybe the sum of them all) is a truthmaker for p, or so it is pretty standard to think. But while a horse makes there be horses, a horse is not enough to make it be true that there are horses, since the latter claim involves something other than a horse, namely the proposition p. So, we need to distinguish between making there be horses and making it true that there are horses. A horse suffices for the former task. But for the latter task, we need a horse, p, and whatever relations and properties are involved in the attribution of truth to p (e.g., an instance of a correspondence relation). (I am grateful to Dan Johnson for helping me get clear on what this latter task involves.)

We now have a linguistic question. Is the "truthmaker" of p just a horse, or a horse, p and whatever else is needed? Since "truthmaker" is entirely a stipulative term of art, nothing deeply significant rides on this question, but the question does have two aspects: the sociological question of just how the word "truthmaker" has been used by philosophers, and the question of which way of using the word gets at a more fundamental concept. Say that a "truthmaker(1)" is the concept that goes with the answer "a horse" and a "truthmaker(2)" is the concept that goes with the answer that also includes p. Then there is a natural way of defining truthmakers(2) in terms of truthmakers(1). The truthmaker(2) of p is identical to the truthmaker(1) of the proposition that p is true. One might try to define a truthmaker(1) in terms of taking a truthmaker(2) and subtracting the proposition and the relation, but that definition will be messy and difficult to give. So, it seems that the truthmaker(1) is the more fundamental of the two concepts. Moreover, sociologically, I think "truthmaker(1)" is the right reading of how "truthmaker" has been used, because as a matter of fact most users of truthmakers don't include the proposition and the correspondence relation in the truthmaker.

But now we see that unless we have a deflationary theory of truth, the term "truthmaker", understood as truthmaker(1), is a bit of a misnomer. For the truthmaker of p isn't what makes p be true. It is only a part of what makes p be true: makes p be true is not just the truthmaker(1) but also p and how its related to the truthmaker(1).

It may, of course, turn out that deflationary theories of truth are correct. But unless deflationary theories are established to be true, as much of our theorizing as possible should be compatible with non-deflationary theories as well, and so we should be sensitive to the difference between the condition that p and the condition that p is true.

Two other areas where the distinction could matter are these: (1) Is it a part of our concept of knowledge that if x knows p, then p is true, or should we rather say that if x knows p, then p? (2) Should we require it to be a part of omniscience that for all p, God knows p if p is true, or that for all p, God knows p iff p? With a bivalent logic and an acceptance of Schema (T) as a necessary truth, the answers are going to be necessarily extensionally equivalent. But conceptually there may be a difference, and how we answer (1) and (2) may affect some of our intuitions.

Such sensitivity will also be important when we consider non-bivalent logic, even if we only consider them to dismiss them. For instance, suppose we deny that contingent propositions about the future are true or false, but accept excluded middle. Then if we understand omniscience as implying that God knows p if p is true, God can be omniscient without knowing contingent propositions about the future. But if we understand omniscience as implying that God knows p if p, then omniscience requires God to know some contingent propositions about the future, even if none such are true.

Explanation and truthmakers

Say that a true proposition is ontologically ungrounded provided that it is not true because of any combination of what things exist, how things that exist exist and what things do not exist. In particular, an ontologically ungrounded proposition lacks a truthmaker.

It would be really nice if one could argue that:

1. No contingent ontologically ungrounded proposition has an explanation.

For if we could show (1), then we would have a neat argument against those presentist views on which truths about the past are ontologically ungrounded (e.g., Trenton Merricks). For some truths about the past have explanations: that World War II happened is explained by Germany's humiliation after World War I, say. We might also have an argument against the version of Molinism on which conditionals of free will are ontologically ungrounded. For some conditionals can probably be explained in terms of others: That George in circumstances C would greedily accept the bribe explains that he would accept the bribe.

I don't really have a good argument for (1), apart from the fact that it rings true. But, then again, I am no friend of ontologically ungrounded propositions, so my intuitions aren't the best judge here.

However, while (1) is hard to argue for, I think the following is pretty easy to argue for:

2. No contingent ontologically ungrounded proposition has a causal explanation.

After all, to causally explain a proposition is to give a cause of that in the world which grounds its truth. Causation is a relation between things in the world (possibly including absences, too), while causal explanation is a relation between propositions that depends on causation. I don't know whether (2) is enough to refute Molinism. But it does seem enough to refute the ungrounded past view. That World War II happened is, after all, causally explained by the fact that Germany was humiliated.

Perhaps the presentist will say that World War II was causally explained by the humiliation. But when? As I understand it, when World War II started, the humiliation was already gone. Thus, at no time were World War II and the humiliation both present. Hence, at every time we have a causal explanation relation between two propositions at most one of which reports an ontologically grounded fact. But how can there be a causal explanation relation between two propositions one of which is ontologically ungrounded?

I suppose this is a variation of the old causation objection to presentism.

Platonism

Jerry waltzes. According to the Platonist, this means that Jerry instantiates the universal waltzing. So, where initially we thought we had Jerry alone, we now have Jerry, instantiation and waltzing. But we also, equally, have Jerry, instantiation and waltzing when Jerry is sitting instead of waltzing. After all, instantiation and waltzing are universals, and so they exist necessarily, even when Jerry isn't waltzing. So, what is different between the situation where Jerry instantiates waltzing and the one where he does not? It won't help to say that the ordered pair <Jerry, waltzing> instantiates instantiation. For the same problem reappears. Whether Jerry waltzes or not, Jerry, waltzing, the ordered pair <Jerry, waltzing>, and instantiation necessarily exist. Going to further levels of the regress will get us more entities, but it will not help resolve the problem. For we will simply get more beings that exist even when Jerry isn't waltzing, and those beings don't help to differentiate betweent he case of him waltzing and him not waltzing. (Nor does this depend on time; we can distinguish between the case of Jerry's instantiating waltzing at some time or other and the case of Jerry's not instantiating waltzing at some time or other.)

So what can the Platonist do? Well, she could just say that it's simply a fact, a fact not analyzed in terms of further Platonic entities, that Jerry in fact instantiates waltzing, or that <Jerry, waltzing> instantiate instantiation. But then she says exactly the same sort of thing that the ostrich nominalist does. And if she says it in this case, why bring in instantiation at all? Why not just say that Jerry in fact waltzes, and be done with it? Or maybe the Platonist will say that there is a state of affairs of Jerry's instantiating waltzing or <Jerry, waltzing> instantiating instantiation. Fine, but why do that? Why not just say that there is a state of affairs of Jerry's waltzing, and be done with it? Or perhaps the Platonist will posit a trope of instantiating present in <Jerry, waltzing> or a trope of instantiating-waltzing present in Jerry. But why not, then, just posit a trope of waltzing in Jerry?

I do not think this kills Platonism. It just shows that if Platonism is to do something useful for us, it is something other than helping us understand the nature of predication. For if Platonism is seen as helping with predication, it does this by reducing all predication to predications of the form "x instantiates P" or "<x,P> instantiates instantiation". Now in some cases, it is helpful to ground all instances of a class in terms of a distinguished subclass. Thus, in my dissertation, I argued that all modal claims should be grounded in claims about the powers of things. The latter claims are, of course, modal. However, if such a grounding is to have any usefulness, the distinguished subclass must be somehow preferable, maybe epistemologically, maybe in terms of comprehensibility, or in some other way. But why should, say, the state of affairs of Jerry's instantiating waltzing be preferred to the seemingly simpler state of affairs of Jerry's waltzing?

Now it may well be that Platonism has other uses than helping with problems of predication. It may indeed.

Homogeneity of grounding and groundless presentism

The Grounding Homogeneity Thesis (GHT) is not a precise claim, but a guiding principle that, ceteris paribus, we should prefer philosophical theories on which pairs of statements that have similar logical form have similar kinds of truth grounds or else resemble each other in not having truth grounds. For instance a piece-meal metaethical theory on which what makes stealing be wrong is that it violates the categorical imperative while the fact that murder is wrong has no truth grounds at all violates GHT.

Groundless Presentism is Trenton Merrick's theory on which claims about the past and the future are just true, and there is nothing to make them true. Crisp argues against Groundless Presentism basically on the following grounds. It is now 9:25 am. Then the following two statements are true:

1. Pruss is (tenseless) writing a blog post at 9:25 am.
2. Pruss is (tenseless) writing a blog post at 9:20 am.

But on Groundless Presentism, (2) has no truth grounds, while (1) has truth grounds—my present writing. Yet (1) and (2) seem to have the same logical form.

Question: Can the Groundless Presentist just deny the apparent similarity of logical form? If so, then she is committed to the view that one can't read logical form off the words—one may need to know when a statement is being uttered, for instance. I actually agree, but it is a controversial view.

Change of facts and an argument against presentism

Patricia is a person with a strange defect. She has tensed beliefs that she fails to update. For instance, she believes that the Battle of Waterloo was two hundred years ago, and she does not change in respect of this belief—she believed twenty years ago that the Battle of Waterloo was then two hundred years ago, and in twenty years she will believe that the Battle of Waterloo will then be two hundred years ago. Presentists tend to think that the objects of beliefs are tensed propositions, and if so, then it is very plausible that her mind is intrinsically in the very same state with respect to the Battle of Waterloo in 1988, in 2028 and in 2015.[note 1] Interestingly, her belief about the Battle of Waterloo was false in 1988, is false now, will be false in 2028, but on June 18, 2015, her belief will be true.

If Patricia's believings about the Battle of Waterloo do not change intrinsically while they change from false to true to false again, it follows that this change from false to true to false is a Cambridge change. But Cambridge changes are relational. Now in the case of a Cambridge change in x, there is a y distinct from x which changes intrinsically and the change in x is a change relative to y, and x has the changing extrinsic property in virtue of y's having the changing intrinsic property. Thus, what makes Patricia's believings change in a Cambridge way from false to true to false is that something else changes intrinsically.

So what is it that changes intrinsically in virtue of the change in which Patricia's believing changes from false to true to false? Well, the only plausible candidate for an answer to this is that the object of the belief changes intrinsically. When someone falsely believes it is raining and continues to believe it until it becomes true, the belief changes in truth value in virtue of the weather changing from, say, sunshine to rain. But then Patricia's beliefs must be about something in reality. In particular, presentisms like those of Merricks on which there are no truth grounds for facts about the past are going to be falsified by these considerations.

What about presentisms like those of Bigelow and Crisp on which there are past-tensed presently existing states of affairs? Do those do better? I think not. For when a belief changes in truth value without intrinsically changing, I think it must change in virtue of a change in that which the belief is about. But the belief that the Battle of Waterloo was 200 years ago is plainly not about any present state of affairs.

One way out for the presentist is to say that believings change in correctness in virtue of a change in the truth value of the proposition that forms their content. This is intuitively wrong—believings should change in virtue of a change in that which they are about and except in higher order cases they are not about a proposition—but let us pass on that objection. But now the problem reappears in respect of the change in the truth value of the proposition (see also this past post). It does not appear that there is any intrinsic change in the proposition when it changes in truth value. For suppose that the proposition that it is raining changes in truth value with the weather. Surely, then, it changes because of the weather. But how can changes in the weather, changes in the physical world, explain intrinsic changes in the Platonic realm of propositions? (And we need to be realists about propositions for the present suggestion to have any force.) That seems very much implausible. So the proposition changes in truth value in an extrinsic, indeed Cambridge, way. But now the same problem we had with believings reappears at the level of propositions.

An argument against presentism

Presentism holds that only presently occurring events exist. You and I are watching an exciting game of tennis. Our particular interest is drawn by Federer's next serve which is at a match point. With eager anticipation I speculate about how the serve will go. Federer is serving. You briefly respond to my remark during the serve itself, saying that my speculation doesn't look right. Federer has served and wins the match. We continue disagreeing about the serve for the next fifteen minutes. Such a conversation is perfectly natural.

It seems essential to understanding how the conversation goes that we are all the time talking of the same serve. I claimed before the serve that it was going to be and then continue to maintain that it was a beautiful topspin. You claim that the serve was a poorly executed topspin-slice which only won the game by a fluke.[note 1]

It is difficult, however, for the presentist to maintain that we are talking about the same thing. After all, my initial remark, according to presentism, is about the future existence of a serve (note that on open-future presentism, it is not even yet the case that the serve will exist). Your next remark is about an existing serve. My next one is about a serve having existed. What unifies the topic of these remarks? After all, they are only a disagreement if they concern the same serve.

Moreover, consider the state of affairs that I am claiming to obtain, the state of affairs of the serve being an excellent topspin. Let us suppose I am right. Then it seems I am continually pointing to the same state of affairs throughout the conversation. I am certainly not changing my mind—I am too pigheaded for that. Consider now the truthmaker of my claim.

There are two kinds of presentist views about the truthmakers of claims apparently about past or present events. On a Bigelow kind of view, these truthmakers are presently existing but tensed concrete (i.e., non-abstract) states of affairs. On this view, I am initially claiming the obtaining of the concrete state of affairs of an excellent topspin being about to soon be served. You respond, during the serve, with a denial of the occurrence of the concrete state of affairs of an excellent topspin being presently served. I pigheadedly affirm the obtaining of an excellent topspin having been served. How is there any disagreement here? I first maintain the occurrence of one state of affairs, to which you respond with the denial of the occurrence of a second, and then I respond with an affirmation of the occurrence of a third? It seems plain that according to this kind of presentist we are talking about three different states of affairs, one of which (the one talked about during the serve itself) includes a serve, and the other two of which do not (since there are no past or future serves according to presentism).

Moreover, while the point is most vividly made concerning conversation that straddles the time of the event talked about, the point also can be made in regard to a distant past event. Suppose you and I are discussing the Battle of Waterloo. What makes it be the case that we're talking about the same battle? We can't just be talking of the present state of affairs of there having been such-and-such a battle. For there were many battles in the past. Rather, we're talking of the present state of affairs of there having been a battle x seconds ago. But the x keeps on changing, so the state of affairs we're talking about keeps on changing on us.

The second kind of presentism, ably defended by Merricks, holds that there are no truthmakers for typical past and future tensed propositions. Then my first claim, made before the serve, has no truthmaker. Your denial of the claim, during the serve, is the denial of a claim that in fact does have a truthmaker—the presently occurring serve. And then my subsequent re-affirmation is the re-affirmation of a claim that, again, does not have a truthmaker. Plainly you and I are not talking about the same thing, since there is no truthmaker homogeneity (two propositions are truthmaker-homogeneous iff they both lack truthmakers or they both have truthmakers of the same kind) between what I say and what you deny.

Presentism

On one of the best presentist accounts we have, namely that of Trenton Merricks, statements that some proposition p was or will be true are to be understood as embeddings of p in the context of a was or will modal operator, which modal operators are analogous to modal operators like M (possibly) or L (necessarily) or in a work of fiction or ought to be the case. Moreover, even if p is the sort of proposition to normally have a truthmaker, was(p) and will(p) do not have a truthmaker. Call this "modalist presentism."

Here is a problem for modalist presentism. There are a number of contexts in which we stand in the same kind of relation to a proposition about the past or the future as to an analogous proposition about the present. One kind of case I've already discussed in another post, the case of induction: we treat claims about past, present and future on par with respect to induction. A different set of cases are provided by certain non-first-person attitudes (this idea comes from Parfit). If my child is to undergo a painful medical procedure this afternoon, I will be pained at his undergoing the painful experience. Suppose that I am today out of causal contact with my child. I do not think it should matter much to my attitude right now towards the child's experience whether the experience has just occurred, or is now occurring, or is about to occur. And even if there is a difference, there is a common core of compassion in all three cases. Similarly, if I have heard that a friend will today receive a teaching award, I will be glad for his sake. Supposing I am unable to attend the ceremony, it will not matter vis-à-vis my gladness whether he has received the award five minutes ago, or is receiving it now, or will received it in five minutes.

The non-presentist has a way of explaining and justifying the common core of the inductive and emotional attitudes: in all cases, the attitude is a response to the reality of some situation. The feeling I have towards my child's actual pain, whether past, present or future, is different in kind from the feeling that I have towards facts of the form Q(my child is in pain) where Q is some modal operator like M or in a work of fiction. (The case of L is different, but that is because Lp entails p.) Likewise, I treat past, present and future occurrences on par for inductive purposes, and recognize the difference between these and possible or fictional occurrences. In fact, we might even say that a good test for whether I take a situation to be real is whether the situation enters into my inductive and emotional attitudes in these kinds of ways.

But for the modalist presentist, my child's having suffered pain is related to my child's presently suffering pain in somewhat way that my child's possibly suffering pain is related to my child's actually suffering pain. So now we have a problem for the presentist: to explain why it is that there is a pattern of attitudes that are equally appropriate towards situations within the scope of was and will operators as towards present situations, without adverting to the reality of these situations.

Here's a different way of formulating the worry, one that will affect even non-modalist presentists. It seems that what makes it appropriate to have the same attitude of grief or joy at various true propositions, and to engage in inductive reasoning about such propositions, is that these propositions have a truthmaker homogeneity: they are all made true by similar kinds of things. But the presentist denies truthmaker homogeneity between reports of past, present and future pains, as well as between reports of past, present and future raven blackness. The present-tense reports have ordinary sorts of truthmakers, like black ravens or people suffering. The past and future tense ones either have no truthmakers (Merricks) or have truthmakers of a significantly different sort (Bigelow, Crisp) from the present tense ones.

It might be thought that while the presentist has trouble explaining and justifying the lack of difference in these kinds of attitudes, the eternalist has trouble explaining and justifying the difference in first-person attitudes. I care a lot about whether a painful experience is past, present or future. But this is not a problem for the eternalist. For the justification of an attitude often lies not just in the objective features of the situation towards which one has the attitude, but also in a relation to the situation. That a situation is earlier than, simultaneous with or later than an attitude can affect whether the attitude is appropriate or not. And this indexical difference seems to matter a lot more in the case of situations that involve one oneself.

Truth and grounding

Say that a proposition p is "grounded" provided that it has its truth value solely in virtue of reality being a certain way, i.e., of some fact about the existence/non-existence of entities and the possession/non-possession of properties/relations by entities, and the proposition is about reality being in this way.

Say that a proposition p is "extrinsically truthvalued" if and only if either p has truth as an extrinsic property or p has falsehood as an extrinsic property.

The following claims seem to me to be true:

1. A non-self-referential proposition is necessarily grounded iff it is necessarily extrinsically truthvalued.
2. Some non-self-referential propositions are necessarily grounded.
3. Some non-self-referential propositions are necessarily extrinsically truthvalued if and only if all non-self-referential propositions are necessarily extrinsically truthvalued.

It follows from the above claims that all non-self-referential propositions are necessarily grounded. Claim (2) seems the least controversial. Singular existential propositions are, clearly, necessarily grounded. Claim (3) is a claim that the truthvalue of a proposition is ontologically homogeneous across non-self-referential (nsr) propositions—either truth/falsity is always an extrinsic property of a nsr proposition, or it never is. This seems plausible to me.

Claim (1) seems the most controversial to me, but one direction is pretty plausible. If a nsr proposition p is grounded, then it holds or fails to hold in virtue of reality being a certain way, and is about reality being that way. Moreover "reality being that way" does not involve an intrinsic property of p, since if it did, then p would be self-referential. So, if a nsr proposition p is grounded, its truth/falsity is a matter of something extrinsic to p. What is most controversial, I think, is the claim that if truth is extrinsic to p, then p is true in virtue of some reality being a certain way. But even this claim seems to have signfiicant plausibility. If truth is extrinsic to p, then p is true in virtue of being related or not related to aspects of reality beyond p in some way. And it is rather plausible, then, to suppose that those aspects of reality are ones in virtue of which p is true and about which p is.