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Wednesday, March 27, 2013

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Hi Bill,

This is a helpful post. I'm beginning to get the sense that I am simply missing something, however.

As I mentioned in my last comment on the post that inspired this post, I think the ersatzer has the resources to say that Obama is temporally present. To be temporally present is to be such that, when a certain proposition (or certain propositions) is true, you will exist. So, Obama is temporally present because when a certain proposition is true, he will exist. Which proposition? The present time.

You say that this approach puts the cart before the horse, because it is the fact that Obama is temporally present that explains why a certain proposition is the present time. I'm not sure. I think it will depend on your views about the coherence of a tenseless notion of existence. Suppose there is a coherent notion here. Then we can say that a certain maximal proposition is present if and only if it is true, and that proposition is true if and only if reality is as it describes. Obama is present, on this view, just in case when a certain proposition is true, he will exist. Take a certain proposition. Is it true? That depends on whether reality is as it describes, or whether reality makes it true. If there is a coherent notion of tenseless existence, we can say that concrete reality - which exists tenselessly - makes true a certain maximal proposition, which is identified as the present time. Obama is present just in case his tenseless existence is entailed by the present time.

If tenseless existence is incoherent, then it may be right that the ersatzist approach gets the order of explanation backwards. But I'll have to think about (a) whether that notion is incoherent, and (b) whether that conclusion follows from the incoherence of that notion.

If what I've said is plausible, though, then the presentist ersatzer can respond to both of your arguments. He can say, with some propriety, that the concrete universe is temporally present, because it is such that when a certain proposition is true, it will exist. And he can say that the concrete universe does not need to have that property in order to serve as the truthmaker for the maximal proposition that is the present time. Its tenseless existence makes it the truthmaker for that proposition, and then he can say - in a sort of derivative way - that the concrete universe is present because its existence is entailed by the present time.

Now I'm going to go back and look at some of your posts about tenseless and amodal existence.

John,

Thanks for discussing this difficult topic with me.

There are many times (maximal propositions), but only one is temporally present (true). What makes a given time present? It must be the concrete universe U which serves as the truth-maker of the true maximal proposition. Not only that: it must be the present state of U that makes the present time true and present.

It seems obvious to me that the metaphysical ground of the presentness of the present moment is the presentness of U, and not the other way around. In general, it is the obtaining of the truth-maker that explains (metaphysically grounds) the truth of the truth-bearer.

My point is that you involve yourself in a circular explanation if you try to make temporal presentness into a property of a proposition. For if p is temp present, then it is temp present in virtue of a relation in which it stands to a non-proposition U that must be temp present in order to make p temp present.

It just now occurs to me that there is a second problem. Are you thinking of propositions as omnitemporal? If so, then they are such whether true or false. And that holds for max props as well. So all times are temporally present (because times are propositions and all propositions exist at every time) which implies that temporal presentness cannot be identified with truth.

If, on the other hand, propositions are timeless entities, then they cannot change. But that contradicts the requirement that they change their truth values. The present time goes from true to false when the present time becomes past.

By the way, whose views are we talking about here? Can you cite me some literature?

John writes,

>> So, Obama is temporally present because when a certain proposition is true, he will exist. Which proposition? The present time.<<

So Obama's being present is explained by the presently true maximal proposition's including or entailing *Obama exists.* That strikes me as circular. For only if Obama is present will the maximal prop be true.

Temporal presentness, like existence, cannot be 'kicked upstairs': it cannot be made into a property of abstracta. Temporal presentness is a monadic feature of the concreta that make up the universe.

>>Take a certain proposition. Is it true? That depends on whether reality is as it describes, or whether reality makes it true. If there is a coherent notion of tenseless existence, we can say that concrete reality - which exists tenselessly - makes true a certain maximal proposition, which is identified as the present time. Obama is present just in case his tenseless existence is entailed by the present time.<<

But isn't the whole point of presentism to deny that concrete reality exists tenselessly? It may be that in the formulation of the presentist thesis we must make use of a tenseless notion of existence in order to evade the Triviality Objection. But the intent of the presentist is to say that only what exists at present exists. Obama exists at present, hence he has the A-property, presentness. It is because he has this A-property that *Obama is now present* and *Obama now exists* are true. And it because he has this A-property that the max prop that happens to be the present time is true. And not the other way around.

So I am just not following you.

This sort of critique extends, mutatis mutandis, to Plantinga's attempt to make actuality a property of abstracta.

I'm not defending the ersatz view, Bill, but I do have a question about something you said at 11:36:

<< If ... propositions are timeless entities, then they cannot change. But that contradicts the requirement that they change their truth values. >>

This doesn't strike me as a contradiction. If propositions are timeless then they can't change intrinsically, but, with the possible exception of certain necessary truths, truth isn't an intrinsic property of proposition. So change in truth isn't an intrinsic change. Indeed, I would think it's a mere 'Cambridge' change. If that's right, then change is truth values doesn't threaten the supposed timelessness of propositions any more than, say, a change in whether Billy Bob believes in God threatens the supposed timelessness of God.

Alan,

The Cambridge suggestion occurred to me, but then I dismissed it. I grant you that change in TV is a relational change, not an intrinsic change. For example, the proposition *Tom is seated* goes from T to F when Tom stands up. The real change is in Tom; there is no real change in the proposition.

Nevertheless, the proposition has different properties at different times. So it seems it must be in time to have different properties at different times. It must be subject to temporal becoming even if it cannot really change.

But this is not very clear to me. I feel the force of the Billy Bob example. If I press my argument then I have to deny that God and abstracta are timeless -- and then I contradict what I say elsewhere.

There is presentist ersatzism and presentist fictionalism. Do you gentlemen know anything about the latter? I suppose it is the analog of modal fictionalism.

Hi Bill,

I think I am sympathetic to the view that Alan suggested, namely, that although maximal propositions exist omnitemporally, they can change their truth values. I think there is an important point here about two different approaches to propositions. Propositions that are indexed to times cannot change their truth values. But the maximal propositions here cannot be indexed to times because, for the presentist ersatzer, they just *are* times. So they are not indexed to times, and so it seems to me that there is no difficulty in supposing that they can change their truth values.

I have a question concerning what you posted at 11:36 that may help get at our disagreement. You say it is not only the concrete universe U which serves as the truthmaker of the true maximal proposition, but the present state of U. If so, then I have got the order of explanation backwards or, worse, involved myself in circularity.

Here is Craig Bourne's definition of presentism: "ersatzer presentism is the view not that only one time exists but that only one time has a concrete realization" (Bourne, A Future For Presentism , 54). So I think someone like Bourne would say that there is no other state of U other than the present state. So of course it is the present state that is the truthmaker for the present time; there is no other state.

That's not as perspicuous as I would like. But the thought is this. You say that it must be the *present state* of the universe that serves as the truthmaker for the present time. Suppose there is an object o that at time t1 has the property of being F, and that at time t2 loses that property; it is G instead. Suppose further that t2 is the present time. The fact that o is G is the truthmaker for t2. And the reason that t1 is not present is that it is false, because o is no longer F. On the ersatzist view, objects have monadic properties like being F or being G, and when they lose such a property, they no longer instantiate it. It is o's instantiation of G, and failure to instantiate F, that makes t2 present. And that is the present state of the concrete universe, but that is the *only* state of the concrete universe. o's being F is now in the past, but the past is not concrete.

Again, that's not as perspicuous as I would like, but I think it is essential to isolating our disagreement. You want to insist that it must be the present state of the universe, as opposed to some other state of the universe, that serves as the truthmaker for the present time. But I want to say that there are no other states of the universe so long as a state of the universe is supposed to be concrete. So there is no worry here about having to isolate a particular state of the universe to serve as a truthmaker; the concrete universe is as it is, and whichever maximal proposition describes it accurately is the true (i.e., present) one.

If that's right, then - again assuming some tenseless notion of existence - the ersatzer can avoid your concerns about circularity (I think). It is also instructive because presentist ersatzers (such as Bourne) will deny your claim that "the whole point of presentism [is] to deny that concrete reality exists tenselessly". The ersatzer will say that just one time has a concrete realization, and that this concrete realization exists tenselessly. That preserves the main presentist intuition that only one time exists while solving a variety of difficulties, most importantly, the threat of having a trivially true or obviously false thesis.

I haven't really thought much about presentism until now. I've been thinking more about modality, but I need to think more about presentism.

>> You want to insist that it must be the present state of the universe, as opposed to some other state of the universe, that serves as the truthmaker for the present time. But I want to say that there are no other states of the universe so long as a state of the universe is supposed to be concrete. So there is no worry here about having to isolate a particular state of the universe to serve as a truthmaker; the concrete universe is as it is, and whichever maximal proposition describes it accurately is the true (i.e., present) one.<<

My point is that only the present universe could serve as the truth-maker of the present time construed as a maximal proposition. Of course, if presentism is true, then there is no past universe and no future universe. The present universe = the universe. But that doesn't change the fact that the universe has the A-property, presentness. It is U's being present that explains why the present time is present, and not the other way around.

Moreover, U's being present is not U's being true. But the present time's being present is its being true. One cannot therefore identify the presentness of U with the truth of a proposition.

I grant you that the following expressions are extensionally equivalent: 'U,' 'existing U,' 'present U,' 'presently existing U.' But it doesn't follow that there is no property of presentness had by U, or that U does not have presentness. Given that there is a first-plevel property of ptresentness, asnd that it is had by U, the presentness of U cannot be the truth of a proposition.


>>If that's right, then - again assuming some tenseless notion of existence - the ersatzer can avoid your concerns about circularity (I think). It is also instructive because presentist ersatzers (such as Bourne) will deny your claim that "the whole point of presentism [is] to deny that concrete reality exists tenselessly". The ersatzer will say that just one time has a concrete realization, and that this concrete realization exists tenselessly. That preserves the main presentist intuition that only one time exists while solving a variety of difficulties, most importantly, the threat of having a trivially true or obviously false thesis.<<

So you want to say that U makes true the present time (PT), but that U exists tenselessly. Can you explain that to me? I just don't get it.

Consider a mundane example of truth-making. My being seated makes true *BV is seated.* The proposition is present-tensed. You want to say that the T-maker exists tenselessly. But I say that the concrete state of affairs must obtain (exist) at present if it is to make true the present-tensed truth-bearer.

Same with U as truth-maker of PT.

Besides, what do you mean by 'tenseless'? Can you give a definition?

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