Friday, November 24, 2006

Presentism and Relativity

Familiarly, the presentist faces an objection from special relativity. If presentism is true then only presently existing things exist. What is present is simultaneous with your reading this. So what exists are all and only the things that are simultaneous with your reading this just now. But what is simultaneous with your reading this just now is relative to a frame of reference. Therefore, what exists is relative to a frame of reference. But that’s nuts, so presentism is false.

What does the presentist need to do? Well, they win the game, presumably, if they can give some reason for privileging one reference frame over any other, for in that case they can claim simply that what exists is what is simultaneous with your reading of this according to the privileged reference frame. But how can they have a reason for thinking that one reference frame is privileged (without resorting to claiming that God smiles upon one and not the others)?

What we need is a truthmaker for the claim that some reference frame is privileged. Easy! Remember that to exist is to be present. So consider all the things that exist – they are all and only the present things. So surely the privileged reference frame is just that one according to which exactly these things are simultaneous. In that case the truthmaker for the fact that this is the privileged reference frame is just what makes it true that those things exist – namely, those things.

So the thought is this. Everyone in this debate agrees that there is a unique set, S, which is the set of the existing entities. (If you give up on that you don’t get to say ‘but that’s nuts’ in the original argument against presentism.) This (correct me if I’m wrong – I may be (not for the 1st time!) misunderstanding the physics) lets us single out a unique reference frame: the unique reference frame according to which exactly the members of S are simultaneous. And so, if we’ve got good reason to think that everything that exists is present then we’ve got good reason to think that this frame is the privileged reference frame. Since everything in S exists then everything in S is present; so they had better be simultaneous; so the reference frame that says they are simultaneous is obviously the privileged one.

Convinced? I imagine not. Nor am I. But what’s wrong? I’m finding it hard to put my finger on it. What more is needed from the presentist? Or what are they doing that’s illegitimate?

24 comments:

Ocham said...

I found this completely baffling, probably because I don't understand your definition of 'presentism'. The view that 'only presently existing things exist'? But what does 'presently existing' give us that the present tense of the 'exist' does not? Whatever used to exist, but no longer exists, no longer exists, and so doesn't exist. What will exist, but doesn't yet exist, doesn’t yet exist, and so doesn't exist. What else is left over? Or explain how what no longer exists, or what doesn't yet exist, can exist now?

And you say 'Remember that to exist is to be present'. Well, to exist *now*, is to be present. But to have existed, is not necessarily to be present, is it?

There is a more interesting point raised by your 'simultaneous with your reading this just now', though I don't understand its logical connection with the scientific theory of special relativity. If you write this sentence on Monday, your 'now' refers presumably to Monday, hence what is denoted by your 'what exists' are all the things that existed on Monday. But I read this on Tuesday (e.g.), so I tend to read the 'now' as refering to Tuesday, and so take what is denoted by your 'what exists' as being all the things which existed on Tuesday. But clearly some things that existed on Monday (the Monday morning meeting, e.g.) no longer exist on Tuesday. So quite what determines the truth of this one, I don't know.

Ocham said...

I can't resist advertising the 'eternity' page on my website, which is a lot of writing on this subject from past ages. The theme of the website (The Logic Museum) is that all philosophical problems have been discussed, but forgotten, and that philosophers are condemned like Sisyphus to relive their past for all eternity – the Museum simply dusts of the cobwebs and presents them for all to see. See in particular Augustine's remarks on Time, which Wittgenstein later made famous.

http://uk.geocities.com/frege@btinternet.com/time/augustineonntime.htm

Augustine says, anticipating presentism: 'Neque id quod futurum est esse iam, neque id quod praeteritum est'. Neither that which will be, nor that which is past, exists now. Why? Because 'si nihil praeteriret, non esset praeteritum tempus, et si nihil adveniret, non esset futurum tempus' - if nothing passed away, there would be no past time, and if nothing were arriving, then there would be no future time.

The truth of this is even more obvious in the Latin. For example, 'futurus' is simply a participle reflecting the future tense of of the verb 'esse', to be. (Which of course is why 'future' is called 'future'). So Augustine is really saying nothing more controversial than that what will be the case, but isn't the case, is not in fact the case.

Ross Cameron said...

I tried to reply and it didn’t seem to work: let me try again.

Presentism is the view that what exists unrestrictedly are exactly those things that exist now. This is neither the trivial claim that what presently exists exists now nor the false claim that what existed, exists now, or will exist, exists now. Given that, I’m baffled by your bafflement.

The presentist think that to exist is to be present. They do not think only that to exist now is to be present. Nor are they saying that to have existed is to be present. They are not stupid (at least, not all of them are). They are claiming something genuinely controversial (unlike Augustine), that the widest domain of existence does not extend beyond the present. That is not a point about our temporal language, it is a point about ontology.

Ocham said...

I still don't understand, because you still do not give a clear or careful definition of presentism.

"The widest domain of existence does not extend beyond the present" is not helpful.

If you are trying to say that the presentist view is that if we cast our net wide enough, we capture only what exists now, how does this differ from the trivial position I described? I mean, what on earth is left over that an anti-presentist would like to include? Would he or she like to include things that used to exist, but no longer exist? But the meaning of 'no longer exists' is 'used to exist, but doesn't any more'. Similarly, 'does not yet exist' means 'does not exist, but will', and so the anti-presentist cannot include what does not yet exist.

But then my question is, what is left over when we subtract (i) what does not yet exist, and (ii) what no longer exists, from everything whatsover that exists? Surely, only what exists now. If the anti-presentist wants to exclude (i) and (ii), the anti-presentist is a presentist.

In my view the whole issue rests on a deep logical confusion, but persuade me otherwise!

Ross Cameron said...

No, the anti-presentist wouldn't include in the widest domain of existence things which used to exist but no longer do. But nor will she accept the inference from 'x used to exist' to 'x no longer exists'. Dinosaurs exist, for the non-presentist. They do not exist *now*, but they exist nevertheless.

I'm not sure I can persuade you that this doesn't rest on a logical confusion. It's kind of like explaining eyesight to the blind. Either you accept that there is a notion of existence simpliciter or you don't. If you do, then it's obvious that presentism is neither trivial nor false on purely logical grounds. If you think the only resources we have available to us are the 'exists now' quantifier or the 'exists now, existed, or will exist' quantifier then of course there *is* a problem. But that's a hugely controversial assumption.

Ross Cameron said...

And incidentally, just because I appeal to resources that you either don't understand or don't accept doesn't mean that my definition (which is not mine anyway, it's totally standard) is neither clear nor careful.

Ocham said...

>>>No, the anti-presentist wouldn't include in the widest domain of existence things which used to exist but no longer do. But nor will she accept the inference from 'x used to exist' to 'x no longer exists'. Dinosaurs exist, for the non-presentist. They do not exist *now*, but they exist nevertheless.

Well, some things that existed in the past (Nelson's column) still exist, so I agree that 'used to exist' does not imply 'no longer exists'. On the dinosaurs thing, I do not agree with the non-presentist. I believe that dinosaurs used to exist, but they don't exist any more. But that is a scientific disagreement. All the evidence seems to be that there are no longer any such creatures. Maybe the Loch Ness monster, but that's not proven, and may have been a hoax.

>>> I'm not sure I can persuade you that this doesn't rest on a logical confusion. It's kind of like explaining eyesight to the blind.

This rather conflicts with your later statement about your definitions being clear and careful. When the answer cannot be put into words, neither can the question. On your definition being totally standard, I'm sure it is.

>> Either you accept that there is a notion of existence simpliciter or you don't. If you do, then it's obvious that presentism is neither trivial nor false on purely logical grounds.

Do you mean that existence is some kind of property, possessed by some things, but not by others? Perhaps the non-presentist means to say 'some things used to exist, but do not exist now', and is trying to express by the words 'some things' a wider sense of existence, that is not possessed in the narrow sense of 'exists now'. As though 'existing now' were a kind of property that some things possess, and others do not (specifically, those things that no longer exist, or which will one day exist)? Is that the point?

Ross Cameron said...

"On the dinosaurs thing, I do not agree with the non-presentist. I believe that dinosaurs used to exist, but they don't exist any more. But that is a scientific disagreement"

No, it's an ontological one. Whether the past exists is an ontological question.

My definition *can* be put into words - I have done it. It contains vocabulary that you don't understand - the unrestricted and tenseless quantifier - but that doesn't make it unclear.

I am not taking 'being present' to be a property. The presentist claim is not that there is a special property that all and only the present things have. The presentist claim is that everything is present. That definition is acceptable to anyone - presentist or eternalist - who understands the unrestrticted and tenseless quantifier used.

Now maybe they're all mistakes to think there is such a quantifier. In that case the presentism/eternalism debate rests on a mistake. I take it this is your view. But it's clearly a substantive issue whether there is such a quantifier: so at the very least it's a substantive issue whether there is a substantive issue here.

But I don't want to get sucked into debating whether or not there is such a quantifier. My original post simply assumes that there is - and it is the issue raised on that assumption that I am interested in. So I'm going to close (at least my part in the) debate over whether or not this defintion makes sense.

Quirinius_Quine said...

Very interesting post. I don't think I have an answer to the question of what's wrong with the presentist's move, but I do have a worry: what is the ontological status of all the "false" or "unpriveleged" reference frames? On the orthodox conception of Relativity all the frames are on a par, just like the possible worlds of Lewis's Modal Realism. Now, in the presentist's scenario, some false reference frames will represent simultaneous things as non-simultaneous. All's well and good so far. But what of the frames which represent some present things things as being simultaneous with things that (objectively) no longer exist? I worry that the presentist will lack the resources to construct these frames, since some constituents will simply not exist; though perhaps they could come up with something like the ersatzist strategy in modal metaphysics.

Jonathan said...

Hi Ross,

On the relativity stuff, you said:

'What does the presentist need to do? Well, they win the game, presumably, if they can give some reason for privileging one reference frame over any other'

I'd like to believe you, but I'm not so sure. It isn't enough that the presentist gives some reason to privilege one frame; they need to explain why we have the appearance of an illusion. It seems that other frames exist, and it seems that all frames are equal. Moreover, these other frames are then used to explain relativistic phenomena - e.g. 'twins' paradoxes, and the like. There's a Lowe/McCall paper in Analysis that deals with how space-time explains stuff. 2003, I think. Sorry, I know I emailed you some of this, but the email I sent was a bit rushed!

But perhaps I've missed your point, perhaps you think the presentist can respond to this via the arbitrariness move. Is that right?

Ocham said...

I'm glad some other people give the appearance of understanding this. Perhaps someone else can give a definition of the terms at issue (presentism, frame of reference &c).

E.g. One of Ross's definitions of presentism was the belief that everything is present. Assuming this means 'everything exists in the present', that implies anti-presentists believe that not everything exists in the present.

But why shouldn't a presentist believe that not everything exists in the present? Dinosaurs don't exist in the present, for example.

This seems like one of those academic discussions where everyone agrees on the jargon to be used, and the rules of the game are that no one can challenge the jargon. And I thought French philosophy was bad.

I was trained in philosophy, by the way. Moreover by a distinguished philosopher who was expert in tense logic and that sort of stuff. Perhaps I missed a trick, but none of this makes any sense to me. Would one of the three people here enlighten me?

Robbie said...

Hi Ocham,

I think Ross was happy to think that *there may be* a position that endorses what you say. That is, it says that the only (relevant) legimitate ways of using "exists" are tensed. There are presently-existing things, there were past-existing things, there will be future-existing things.

Now consider a "tenseless" use of exists: e.g. a sense in which (on a standard view) we can say that Napolean, me, and my great great grandchildren all exist. You might deny that there is any content to that notion. You might think that we should somehow *define it* out of the tensed usages of existence. Both of those are controversial positions to adopt. It's fine for someone to believe them true, but it's not automatically a criticism of someone if they disagree with you on this point. (There are burden of proof issues here, of course: who has to justify their position? And those issues are themselves a matter of controversy). Ross's discussion is presupposing (I think) that there is a tenseless sense of existence, and it's not just defined out of the tensed notions. So let's suppose there is such a thing.

Now, I just said that on the "tenseless" sense of existence, it might be that Napolean, me, and my great-great grandchildren all exist. That's a natural view, and one endorsed by many. But there's room for dispute about how tenseless and tensed usage of "exists" relate to one another. (It's only not a matter of debate if one is defined in terms of the other: but that's not the view now under consideration.) The presentist now says the following (controversial) thing: only things which are present (tenselessly) exist. Maybe we can *make sense* of saying "In the past, there existed dinosaurs". But we can also make sense of "In Sherlock Holmes stories, there existed a detective in Baker St". The presentist thinks that the former is as ontologically non-committal as the latter. That's a substantive position. You can deny it's presuppositions, or disagree with it. But it's not crazy or contentless.

Anti-presentists deny this. They think that some of what (tenselessly) exists isn't located at the present time. You can also deny the presuppositions of this way of talking, or disagree with it. But it's not crazy or contentless.

I think what was generating frustration is *not* that the position you seem to be adopting (something like: there's no intelligible tenseless sense of existence) is not a player on the philosophical scene. It's that it isn't the *only* way to think about these matters, nor is it clear that it is the "most natural" way to think about these matters, so that other positions would have to define their positions in e.g. tensed terms in order to count as intelligible.

And I do mean it when I say that these positions are controversial: none of this terminology is beyond dispute or discussion (it's not the kind of "jargon" you describe). In fact the opposite: the appropriate terminology is a matter of intense discussion. It's just that it seems to many that the sort of setting Ross was presupposing turns out to be a really attractive one.

Does that help at all?

Ocham said...

Hello Robbie, are you the same Robbie (JRG Williams) who was at Oxford, then St Andrews?

Yes that does help. The position you describe is what I thought Ross was trying to express, but then something else he said completely confused me.

And yes, the position I am adopting is partly that 'there is no intelligible tenseless sense of existence', i.e. of the verb 'to exist'. And for that very reason I have to disagree with the assertion you make, at least twice, that the claims in question are not contentless. (I don't say they are crazy – there are natural and understandable reasons for making them). But that is not my whole point, for we need to consider

(a) The contribution of tense in the verb 'exists'
(b) The (non tensed) contribution of the quantifier 'something'.

What do I mean. Well, I pointed out that the presentist might hold that some things (such as dinosaurs) no longer exist. This is still consistent with his position that only things that in the present, exist, and that things like dinosaurs no longer (and therefore don't) exist.

However, to do this, he has to accept that the quantifier-like expression 'some things' ranges over more things than exist in the present.

Therefore there IS an intelligible tenseless sense of 'exist', in the sense that the term 'some thing' has no tense at all (it is not a verb), and in the sense that it does capture one sense of the concept of 'existence' (though not, of course, the sense expressed by the tensed expression 'exist'). Therefore your characterisation of the dispute as whether 'there is no intelligible tenseless sense of existence' itself requires further clarification before we can make any sense of this.

You say that the view that 'Napole[o]n, me, and my great-great grandchildren all exist' is 'a natural view, and one endorsed by many'. Well, you have to distinguish this view from the kind of view, also held by many, that Elvis still exists. You might say that these people believe Elvis is still alive. But what about spiritualists who believe that Elvis, though technically dead, is still existing in some sense? Presumably you want to distinguish these parapsychological or crank theories from the philosophical theories. But that means being very careful about the sense of 'existence' you are trying to capture. If there is such a sense, of course. The burden of proof, I would argue, is on you guys to explain very clearly and carefully what the various positions are, which none of you have done, yet.

Jonathan said...

Hi Ocham,

(And apologies to Robbie for jumping in on this). One presentist who agrees that we can't make use of a tenseless notion of existence is Tom Crisp. But he's tried to defend presentism from the kind of accusation that you make - namely that it's something like a tautology, or obviously false. Crisp's reading of presentism is, 'For every x, x is a present thing'. Now, you wanted to render a dinosaur objection to the presentist of the form, 'dinousaurs have existed, but exist no longer' - e.g. they were present, but are no longer. Crisp understands that, using WAS to indicate a tense operator, as, 'For some x, x was a dinosaur and x is no longer present'. That, as you rightly say, looks bad.
So what Crisp says the presentist should say is, 'WAS(for some x, x is a dinousaur and x will not exist in tα), where tα is the present at the time of the utterance.
This latter definition seems to meet the quantificational objection (at least no-one has yet shown otherwise in the literature) and isn't tenseless, either, so it should meet your concerns that the quantifier shouldn't be tenseless.
The frame of reference stuff is just standard terminology employed by physicists when talking about the special theory of relativity.

Ocham said...

Hi Jonathan

Just to be clear what I'm objecting to, which is unclear definitions of presentism. Ross gave (at least two) definitions of presentism, as follows:

1. Only presently existing things exist
2. Everything is present

whereas a moment's reflection tells us that 1. can be true, but 2 false, in face of the obvious truth that some things (dinosaurs) no longer are present/exist. I have now also checked Ned Markosian's definition in SEP and he makes exactly the same mistake. He defines presentism as the view that

(1a) Only present objects exist.

but when you read through what he later says, it's clear he means something else, similar to (2) above. So my first objection is to definitions which are not clear or careful.

On the (good) point you actually raise. I wouldn't want to say that 'some things are no longer present' looks bad. Indeed, it is obviously true. You actually write 'For some x, x was a dinosaur and x is no longer present', but there there is the question of what 'for some x' means, and whether existential quantification in predicate calculus translates to the English word 'something' plus tensed verb, which is altogether a separate question, and I have no view on it.

On 'WAS(for some x, x is a dinousaur and x will not exist in tα), where tα is the present at the time of the utterance' that's deeply wrong. It's close to Ocham's (the 14th century one) solution. He says that "A was B" can be analysed is '"A is B' was true'. What's wrong with it is the assumption that the truth of a proposition involves a (presumably tensed) relation between a proposition and the thing that makes it true, which immediately leads to the problem of how a presently existing proposition can (now) be related to something which no longer exists. That's the assumption that leads to all this sort of nonsense.

Robbie said...

Everyone agrees there's a trivial reading of (1). It's only charitable to think that Markosian and Ross weren't intending the trivial reading (which they're both well aware of). They both think there's a non-trivial reading, from which (2) follows.

I know you think one of the presuppositions of this is wrong: but that's a controversial position. I think it's just the wrong way to put your point, to say that the suggested definition is "unclear". What you should be saying is that you disagree with one of the presuppositions of this particular way of characterizing presentism.

You say that various things are "obvious" or "nonsense". That's pretty aggressive language. Why not just say that those things are common-sensical, or seem right/wrong to you? In the end, philosophical positions might disagree with (or explain away) what looks like common sense.

Bryan Frances said...

Good folks,

I think that often enough the central issue in the presentism debate can be formulated without fussing over 'exists'. Many presentists say that we don't stand in any real relations to non-present objects. Non-presentists disagree. The latter say that Socrates is the truthmaker, or part of the truthmaker, for some of our 2006 beliefs and sayings. They say that we stand in causal relations to him. They say that some of our naked quantifiers--without the help of any temporal operators--range over him. Presentists typically construe presentism so that none of these claims hold. That's why that kind of presentism is tough to defend.

A non-real relation would be something like worship (one can worship the largest prime number).

For my part, I'm not convinced that doing justice to presentist intuitions requires one to accept the 'no real relations to past/future objects' kind of thesis. Based on what you know about the presentism literature, would non-presentists be happy if they were "allowed" by presentists to quantify over past objects?

Ross Cameron said...

Good God! Now I see that I am, and always have been, an idiot. If only I'd realised that there are no longer any dinosaurs.

This is why I left the debate. But just when I thought I was out, they pull me back in.

Ocham - you're reading of what I (and Ned) say seems to me like objecting against the Meinongian, who says that some things don't exist, that they commit themselves to a contradiction: that there exist some things that don't exist.

The Meinongian doesn't say that, and it's completely, and obviously, uncharitable to take this as their position. The Meinongian, rather, thinks that there is a quantifier that ranges over a domain wider than the domain of existent entities.

Of course, they may be totally mistaken to think that such a quantifier makes any sense, or to think that having such a quantifier is supported by common sense intuitions. But then *that's* where the debate should focus: not over whether or not they commit themselves to a contradition.

Likewise, it should be obvious to any sensible commentator that Ned and I aren't making the completely elementary mistake you accuse us of making - the mistake that "a moments reflection" will reveal. To accuse us of making this mistake seems to me to be either the result of serious confusion of the result of a complete lack of charity. If it's the latter, that is incredibly bad argumentative practice.

Ross Cameron said...

I meant 'your reading', of course. Not 'you're reading'. This is what I get for typing angry . . .

Jonathan said...

Hi Ocham,

Now *I'm* confused! I'll try and do my best to respond to each of your points as the presentist will.

A: ''Everything is present' is false'
As I noted in reference to Crisp, a number of presentists agree with that, but understand the quantificational commitments as, 'WAS(for some x, x is a dinousaur and x will not exist in tα)' in conjunction with a relevant clause about the future and ontological commitment to the present time. E.g. WAS(x)& (y) & WILL (z).

So now I owe you a response to another point that you make, that, 'He says that "A was B" can be analysed is '"A is B' was true'. What's wrong with it is the assumption that the truth of a proposition involves a (presumably tensed) relation between a proposition and the thing that makes it true, which immediately leads to the problem of how a presently existing proposition can (now) be related to something which no longer exists. '

I'm afraid I can't make sense of that. The presentist view I'm putting forward here isn't that 'A was B' is the type of clause that is in need of analysis, though the differences are subtle.

What I want to say is that, 'there were dinosaurs' is to be understood as WAS(dinosaurs) - more or less. You seem to criticise the view for allowing that ''A is B' was true' to entail the past existence of some thing to make it presently true that 'A was B'. But so far as I can tell saying that WAS(dinousaurs) isn't a present truth. At least, whether or not it's a present truth is something worth debating, rather than assuming. But perhaps I'm misreading you.


Finally, 'I wouldn't want to say that 'some things are no longer present' looks bad. Indeed, it is obviously true.'

Well it looks bad if you're a presentist! Some things (e.g. non-existent dinosaurs) are no longer present. No presentist should like the look of that sentence.

But I don't see that it's an obvious truth. Like Crisp it seems obvious that 'there were dinosaurs', but since that can be expressed by WAS(dinosaurs), I don't see the issue. But again, perhaps I've missed your point.

And just a quick response to Bryan. I'm a presentist and I wouldn't want to say that there are non-real relations, nor would I want to say that we can, now, quantify (in anything like a non-fictional way) over past objects. But then maybe I'm wierd..!

Ocham said...

Robbie:
>> You say that various things are "obvious" or "nonsense". That's pretty aggressive language.

Blame my sense of humour, and a tendency to ignore everything between the blindingly obvious and the absurd. No aggression intended, and I apologise for any offence caused. You say that there is a non-trivial reading of (1) 'Only presently existing things exist' that implies (2) 'Everything is present', and you suggest there is a presupposition behind that reading, and I think it is wrong. Not quite. I'm not clear what the presupposition is. Ross characterised it as

(R1) There are unrestricted and tenseless quantifiers.

But I pointed out that one can hold that there are unrestricted and tenseless quantifiers and still hold that 'some things no longer exist' is true. Also, there is a way of reading 'Everything is present' that is trivial, and not consistent with presentism as (probably) intended. I might read it as consistent with 'some things weren't present' (though not 'some things AREn't present').

Ross:
>>> Ocham – you[r] reading of what I (and Ned) say seems to me like objecting against the Meinongian, who says that some things don't exist,

Not at all. I hold that some things no longer exist. Those things don't exist, though they did.

>>> Likewise, it should be obvious to any sensible commentator …

I thought Robbie said we weren't going to use the word 'obvious'!

Jonathan:
>>> The presentist view I'm putting forward here isn't that 'A was B' is the type of clause that is in need of analysis, though the differences are subtle.

Well, I said it was close, which is consistent with the idea that any differences are subtle.

>>> What I want to say is that, 'there were dinosaurs' is to be understood as WAS(dinosaurs) - more or less. You seem to criticise the view for allowing that ''A is B' was true' to entail the past existence of some thing to make it presently true that 'A was B'.

No, I am criticising (14C) Ocham's view for the assumption it starts with, namely that we need truthmakers at all. It is an adequate response, given the inadequate starting point.

>>>But so far as I can tell saying that WAS(dinousaurs) isn't a present truth. At least, whether or not it's a present truth is something worth debating, rather than assuming. But perhaps I'm misreading you.

The problem is that we would rather like to say that it IS true. Certainly worth debating.

>>> Well it looks bad if you're a presentist! Some things (e.g. non-existent dinosaurs) are no longer present. No presentist should like the look of that sentence.

There's another worth-debating issue here: does the falsity of 'everything exists' imply the truth of 'some things do not exist'? I.e. do we read 'some things no longer exist' as negating the present tense 'exist'? Or do we read it as implying the truth of another present tense sentence, i.e. containing the present tense 'do not exist'?

>>> Like Crisp it seems obvious that 'there were dinosaurs', but since that can be expressed by WAS(dinosaurs), I don't see the issue. But again, perhaps I've missed your point.

Well, remember 'there were dinosaurs' is not enough. You need to express the fact that they don't exist any more, hence decide whether 'There are no longer any dinosaurs' expresses some present tense truth while quantifying over dinosaurs, which you say presentists dislike. (The quantifying, I mean, not the dinosaurs. Clearly they can't, by their own lights, like or dislike dinosaurs).

Ocham said...

A further comment. I mentioned the confusion between two different versions of Presentism, namely a and b below.

(a) everything is present
(b) to exist is to be present

And said that Markosian (in the SEP article on 'Time') does clarify that he means (a) and not (b). Reading that part of the article again, it strikes me that he doesn't. Markosian says that if we were to make a list of all the things that exist, there would not be a single non-present object on the list. But then says that the Taj Mahal would be on the list, but Socrates wouldn't. This is not in fact sufficient to rule out the unintended interpretation. Since someone (Socrates) is not on the list, it follows that (a) is false (since (a) says that to everything is on the list).

David said...

acording to presentists what is the nature of the causal relata? Assuming that in order for x to cause y (or be a cause of y) both x and y must be actual, it would seem that presentists can't have events as the causal relata. Is this right or am I missing something obvious?

Jonathan said...

Hi David,

That seems right to me. But it loooks broadly plausible to adopt something like an agent account of causation. So, x causes y if x changes in the right sort of way to bring about y. I'm taking Lowe's Survey of Metaphysics as the way to understand agent causation, by the way.