There are computers. I think – generally speaking – we can all agree on that. But what about “There are dinosaurs”? Most people would probably say “Ah no, you can only say that there were dinosaurs”. However, from a philosophical point of view this would seem to imply a presupposition about the nature – and scope – of quantification. The presupposition is that existential quantification only ranges over “the present and the things of the present” (whether the same could be said of universal quantification is a moot point). But is there any a priori reason to hold that existential quantification is implicitly tensed and bound to the time of utterance, or does such a view depend on having adopted some metaphysical stance regarding the nature of time?
The view that only the present and the things of the present are real is called “presentism” in recent philosophy of time, and many of its proponents argue that it reflects our intuition about the nature of time. However, it’s not the only view, and to hold that existential quantification only ranges over what is presently the case is thus an implicit petitio principii. While presentism does indeed hold that only the present and the things of the present exist, the view variously known as “four-dimensionalism” or “eternalism” holds that the universe is a structured block of spacetime and that other times are rather ‘elsewhere’ than not yet or no longer real (we could perhaps employ the neologism “elsewhen” to characterise real events occurring at some other time than simultaneously with the time of utterance). On four-dimensionalism, there is no a priori reason to distinguish between “there are computers’ and “there are dinosaurs”. But, on four-dimensionalism, is there any way to render explicit the differentiation between the two that is implicit in the presentist view?
In order to make such a differentiation, we need to examine two distinct characteristics of the temporal scope of existential quantification that, in the supposedly intuitive presentist view, are not separated out. One is that an existentially quantified sentence is true at a time, and the other is that such a sentence is true of a time. Quite understandably, the implicit presentist view treats these two as coextensive: as all existential statements of the kind ∃x [x is a computer] only range over the time of utterance, they are automatically true at the time of utterance and of the time of utterance. But on the four-dimensionalist view, these characteristics are clearly distinct. The statement ∃x [x is a dinosaur] is true at the time of utterance, as the quantifier ranges over all of spacetime. However, it is not true of the time of utterance – dinosaurs are not contemporary with the utterance.
The distinction between the two is not hard to grasp. Even presentists allow for spatial discontinuity – in everyday use, the statement “there is toilet paper” can be true at its place of utterance, but not necessarily true of its place of utterance. When my wife says “there isn’t any toilet paper”, I don’t take her utterance as implying that toilet paper doesn’t exist – I take it as being true of the place of utterance and pragmatically discount whether or not it is true as a general existential statement. So, presentists and four-dimensionalists alike have no difficulty accepting that, pragmatically, her statement has in this case a merely local scope, and that while the unlimited quantification ∃x [x is toilet paper] remains true at its place of utterance, it is not true of its place of utterance.
The question we’re considering here is whether it is actually the case that our everyday use of language intuitively militates for a presentist understanding of time. My view is rather that presentism adopts certain pragmatic uses of language and elevates them to the rank of a metaphysical doctrine. A statement such as “there are no dinosaurs” might, in everyday use, comport an implicit pragmatic localisation in just the same way as “there isn’t any toilet paper”. If my son comes home and tells me he saw a live stegosaur in the park I might well answer “there aren’t any dinosaurs”. But my answer doesn’t imply that dinosaurs are not among the things that exist – I’m merely stating that “there are dinosaurs” isn’t true of the time of utterance. Indeed, the statement “there are no dinosaurs” taken as a standalone would seem to imply a denial of the evidence given by the fossil record.
Here, we could remark that mention of the fossil record allows for a presentist use of the statement “there are dinosaurs” that is true both at and of the time of utterance: there is present (fossil) evidence for dinosaurs, even though living dinosaurs do not (presently) exist. Indeed, it’s unlikely that even a four-dimensionalist would feel comfortable saying “there are living dinosaurs”. In this case, the pragmatic use intuitively takes preference. But this is perhaps no different from my wife saying “there isn’t any toilet paper” – I take it that her statement implies that there is no toilet paper spatially coincident with the immediate locality of her utterance, not that toilet paper is not among the things in the world in general. We could just as well say that “there aren’t any living dinosaurs” implies that there are no living dinosaurs temporally coincident with the immediate (temporal) locality of our utterance, but passes over the question of whether “there are living dinosaurs” is true of the world in general. Everything depends on context, and on what we understand by “the world in general”.
In everyday exchange, the pragmatic element trumps other considerations. When faced with a statement, we instinctively revert to its immediate pragmatic value for the exchange in which it’s employed. Thus, my wife saying “there isn’t any toilet paper” can have different implications according to its immediate context of use. It could imply “so put it on the shopping list”, or it could imply “so take a pack of Kleenex when you go to the toilet”. One would have to be a particularly dogmatic ontologist to derive the implication that she’s stating that toilet paper is not among the things in the world in general. If, however, she were to make the same statement in a philosophy class, we’d more likely ask ourselves whether she holds to the view that there are only fundamental particles and everything else is just a figure of speech to allow for our macroscopic view of the world, or whether she allows for the existence of a certain kind of paper but holds that designating it as “toilet paper” is merely a matter of the use to which it is put (as in the distinction between a long, narrow coffee table and a bench). Likewise, and unless the speaker is Professor Challenger, in most cases any utterance of “there are living dinosaurs” would be taken as a falsehood (as, in universe, it was taken by those who first heard Challenger utter it). But, once again, if the statement “there are living dinosaurs” were to be made in a philosophy class, we could just as well understand that the speaker holds the view that the existential operator ranges over the entirety of spacetime and is using a rather dramatic (and somewhat flowery) way of introducing that view.
Generally speaking, when faced with existential statements in everyday language we tend to interpret them as holding both at and of their circumstances of utterance. Hence, the statement “there isn’t any toilet paper” holds at and of the immediate (spatial) locality of its utterance and “there aren’t any living dinosaurs” holds at and of the immediate (temporal) locality of its utterance. But there is no such limitation on technical uses of quantification. From the technical point of view “there is no toilet paper” is quite simply false, unless we’ve specified that it applies to a (spatially) limited universe of discourse. Similarly, we could argue that in technical use “there are no living dinosaurs” is false unless we’ve specified that it applies to a (temporally) limited universe of discourse. On the four-dimensionalist view, “there are living dinosaurs” is technically true at any time of utterance while not being true of any time of utterance (pace Professor Challenger). But then of course on the presentist view it is false both of and at any time of utterance. Everything depends on the speaker’s background assumptions.
Presentists assume that, while it is spatially unbounded, the existential quantifier is temporally bounded, and point to our everyday experience of time in defence of their view. But their view is founded on a certain understanding of our everyday experience of time – that what is real is determined by it being locally present. But, while this is perhaps true of our immediate experience, there is no a priori reason to hold that this is true of spacetime in general. Certain statements – such as “there are no living dinosaurs” – would seem to contradict setting the widest possible spatiotemporal range, but I believe we can argue that such statements are pragmatically limited, not ontologically limited. A dinosaur is an animal, and as such, a living being. The incidence of “living” in the statement “there are no living dinosaurs” indicates an implicit limitation of the universe of discourse to an immediate temporal localisation, just as my wife saying “there’s no toilet paper” at home indicates an implicit limitation to an immediate spatial localisation.
To the presentist, any existential statement of the kind ∃x [x is Φ] comports an implicit temporal function t such that t(x)=now. But this limits the scope of the existential quantifier to a universe that doesn’t necessarily correspond to the universe of, say, relativistic physics, thus limiting the quantifier to the world of our immediate experience. There’s no reason not to realise such a limitation – after all, the world of our immediate experience is where we happen to live – but there’s also no reason, from the metaphysical point of view, to accept it as an a priori limitation. Ontologically, we can distinguish between statements that are true at a time and those that are true of a time. Whether we choose to do so depends on our prior metaphysical stance – it isn’t inherent in existential quantification itself.