## 1. What is Presentism?



As a bare ontological thesis, presentism can be understood as
**P**:


* (**P**)Only
present things exist.



P is a claim about what exists (what there is), absolutely and
unrestrictedly. As a description of presentism, it's both
mainstream and minimal. That is, many would accept **P**,
or its logical equivalents, as a statement of presentism (e.g.,
Hinchliff 1996: 123; Crisp 2004: 15; Hawley 2014: 48; Emery 2019:
963), but they would acknowledge that more needs to be said to
articulate a complete theory. To flesh out the ontological thesis,
**P** is often contrasted with two other ontological
theses: an opposing view of time, *eternalism* ("past,
present, and future things exist"), and an analogical view in
modality, *actualism* ("only actual things exist")
(see, e.g., Adams 1986: 321; Hinchliff 1996: 123-4; Sider 1999:
326, 2001: 11-12; Noonan 2013: 219-20, 2019: 490-3).
Theodore Sider, for instance, neatly articulates this apparent
mainstream characterisation:



> 
> 
> Presentism is the doctrine that only the present is real. ... A
> presentist thinks that everything is present; more generally, that,
> necessarily, it is always true that everything is (then) present.
> 
> 
> 
> *Presentism* is the temporal analogue of the modal doctrine of
> *actualism*, according to which everything is actual. The
> opposite view in the philosophy of modality is *possibilism*,
> according to which nonactual things exist; its temporal analogue is
> *eternalism*, according to which there are such things as
> merely past and merely future entities. (1999: 325-6)
> 
> 
> 
> Presentists and eternalists make competing claims about temporal
> ontology. According to presentism, only present things exist.
> According to eternalism, past and future things, such as dinosaurs and
> human outposts on Mars, exist as well. These are theories about what
> there is, just like actualism, possibilism, Platonism, nominalism,
> Meinongianism, idealism, materialism, theism, atheism... (2006:
> 75)
> 
> 
> 



Presentists and the rest thus disagree about what exists. When
confronted with W.V. Quine's (1948) three Anglo-Saxon
monosyllables--"What is there?"--presentists
have a simple and distinctive reply: "Only what's
present". Non-presentists demur. Eternalists say that there are
past and future things too. Growing block theorists
("no-futurists") say that there are past and present
things, but no future things. On the standard, mainstream picture,
what's distinctive about presentism is determined primarily by
the distinct claims made about temporal ontology. For a brief, general
overview of this terrain, see the entry on
 time
 (SS6).



The ontological thesis, **P**, requires supplementation.
Consider, for example, a possible world, *w*, at which the
growing block theory of time is true. At the first moment of
*w*, **P** is true. There exists only the first
moment and that moment is present; there are no other moments, and so
the past hasn't yet come to exist. Later on, it will become
clear that *w* isn't a presentist world, even though it
seems initially to satisfy **P**: at the first moment,
only present things exist. For this reason, when being more
forthcoming with a definition of their view, moving beyond mere
slogan, presentism might more perspicuously be rendered as a view that
is *always* true, if true at all (Crisp 2003: 215; 2004: 19,
fn.6; Deasy 2017: 380). So, presentism amounts to the claim that:


* (**PA**)
Always, only present things exist.



Furthermore, along the modal dimension, presentism might be thought of
as a view that is *necessarily* true, if true at all (Hestevold
& Carter 2002: 499; Markosian 2004: 47, fn.1; Ingram 2016: 2868).
Thus:


* (**PAN**)Necessarily,
it's always the case that, only present
things exist.



However, although presentists sometimes make this move, there's
very little discussion in the literature as to whether
**PAN** is preferable to **PA** (cf. Crisp
2003: 215) and, if so, what would justify that preference. (One might
think that metaphysical theses are necessarily true, if true at all.
But this thought is not directly connected to the debate about time
and change, and it is certainly not uncontroversial, so we set it
aside here.) In what follows, reflecting the lack of discussion, we
remain neutral on whether **PA** or **PAN**
is preferred. We follow the wider literature in typically stating
presentism as **P**, rather than **PA**,
though we take it that something at least as strong as
**PA** is intended.



More modifications may be required. First, strictly speaking, on this
characterization, presentism is a thesis that denies the existence of
*atemporal* or *timeless* entities, that is, entities
that aren't present (but aren't past or future either,
because they are not in time). This appears to rule out the existence
of abstract entities, on the presumption that abstracta are timeless.
[See the entry on
  abstract objects .]
 This also appears to rule out the existence of a timeless god, which
is problematic for those that accept "divine timelessness"
or "divine atemporality". [See the entry on
  eternity in Christian thought,
 esp. SS4.1.] One or both of these may be a step too far for some
presentists. Hence, we might be pressed to modify **P**
and restrict it to concrete or physical objects. We're not
forced to make that move, however, since **P** only rules
out such entities insofar as they are understood as timeless.
Presentism is compatible with the existence of abstracta, for
instance, so long as such entities exist now (exist within time). In
any case, timeless abstracta *are* inconsistent with
**P**, but (as is clear) this needn't be of too
much concern. It is unclear how much would be lost from the core of
presentism if we coupled **P** to timeless abstracta or a
timeless god. For some discussion of additional problems with
combining presentism with divine atemporality, see Leftow (2018).



Second, presentism isn't merely the thesis that only present
things exist. This isn't the full extent of the position.
Without qualification, **P** is consistent with the view
that reality is static (or "frozen") and that time
doesn't really pass. But reality isn't that way; our
reality is dynamic. Hence, a full and proper account of presentism
requires more detail. Typically, presentism is thought to include the
additional claim that various things have existed and that others will
exist: Sennacherib's gardens at Nineveh, Boudica, and Marie
Curie all existed, but exist no longer; and, though we exist,
alongside the Taj Mahal, Taylor Swift, and you (dear reader), all of
us will cease to exist at some future time(s), to be replaced by other
things, each of which will go out of existence in their turn. Thus,
presentism commits us to there being a change in what exists over
time, a change in what's present. Frequently (although not
exclusively), presentists describe this change in terms of temporal
passage--the passing of time--or, at least, as closely
related to it. So, presentism can be understood as the following
conjunction:


* (**PC**)
(i) Only present things exist,
  

&
  

(ii) What's present changes.



For those who state presentism explicitly in this way, see Price
(2011: 277), Miller (2013: 346), and Leininger (2015: 726), amongst
others.



Further, since presentism marks a difference between the present, on
one hand, and the past and future, on the other, it's typical
(although, again, not universal) to see presentism described as a
version of the "A theory" of time (e.g., Craig 2000;
Zimmerman 2008; Deasy 2017). Here we understand the "A
theory" as something like the union of the following two theses:
there are genuine, fundamental or "irreducible" properties
of at least some of past, present and future (i.e., so-called "A
qualities" or "A properties"); and, time passes (see
the entry on
  time:
 SS5). For recent explorations of presentism without the A theory
(or, without A qualities), see Rasmussen (2012, 2015) and Correia
& Rosenkranz (2015).



Thus far, our focus has been on saying what presentism is. And, as we
see it, we've reported faithfully what's said typically
about the view in the contemporary literature. But the recent history
of presentism, the view as it appears in the earlier parts of the
20th century, is a little less clear. As far as we know,
Robert Adams is the first to use the name "presentism" in
print (in 1986), though he implies that he isn't the first to
name it--he writes:



> 
> 
> [a] reduction is offered by a view that is sometimes called
> "presentism" by analogy with "actualism".
> (1986: 321)
> 
> 
> 



Before 1986, matters are unclear. Many (rightly) point to Arthur Prior
as an important and historically significant adherent of presentism.
We agree that Prior endorses something like the presentist's
ontological thesis, **P**, when he writes:



> 
> 
> the present simply *is* the real considered in relation to two
> species of unreality, namely the past and the future. (1970: 245)
> 
> 
> 



But we think that it's less obvious that Prior's complete
view on time *is* presentism, as above (see e.g., Fine 1977;
Butterfield 1983; Le Poidevin 1991: 36-40; Jakobsen 2011). [For
detail on Prior's life and work, see the entry on
  Arthur Prior .]
 There are others after Prior, but before Adams (1986) or Hinchliff
(1988), who also *appear* to endorse **P**, such
as Routley (1980). Similarly, we take no stand here on whether such
philosophers are presentists or on what we *should* say about
these definitional debates (cf. Tallant & Ingram 2021).



This concludes our opening sketch. Presentism is the view that only
present things exist and what's present changes (i.e., things
change, time passes); and, it's a version of the A theory of
time. Now, why believe it?


## 2. Motivating Presentism



The most frequently cited reason given for endorsing
presentism--or, at least, treating it as worthy of serious
critical consideration--trades upon some variant of the claim
that it's the "intuitive" or "common
sense" view of time (e.g., Bigelow 1996: 36; Sider 2001: 11;
Markosian 2004: 48; De Clercq 2006: 386; Tallant 2009b: 407; Ingram
2019: 39-43). Many friends agree, and more than a few foes
concede, that there's something compelling about the ideas that
present things really exist, whilst past and future things don't
exist, and that some things begin to exist, and other things cease to
exist (cf. Sullivan 2012: 153-65). Some who look to defend
presentism will rest there with the bare claim that presentism is
intuitive (etc.) and that this gives us reason to think that
it's true.



One way to proceed is to extend this idea. Begin with the intuition
that there's *something* special about the
present--something distinctive. This seems attractive enough. But
how might we capture it in our metaphysical model of time? One way to
do it is to assert that present things are the only things that exist,
that is, to endorse the presentist's ontic thesis. Certainly,
this marks the present as distinctive. And, to the extent that we wish
to capture and preserve the idea that the present is
"special" (in some sense), presentism fares well against
this measure. But, of course, *any* model that privileges the
present in some way or other will fare well against the same measure
(such as the growing block theory, which states that the present is
special in virtue of being the latest moment of existence). So, for
this argument to motivate presentism fully, further argument must be
given for thinking that rival views don't come up to
scratch.



Another way to motivate presentism is via appeal to experience. To
borrow a famous example, consider a headache (e.g., Zimmerman 1998:
212). If a headache exists, it hurts. It can't exist and fail to
hurt. Now, suppose that we endorse the existence of the past (and deny
presentism). Past headaches exist. But they don't hurt (at
least, so goes the claim). If headaches from hangovers last year hurt
us, neither author would be in a position to write this, so severe
would be the pain. Since headaches must hurt, if they
exist--it's part of their essence to do so--past
headaches cannot exist. This goes for the future headaches as well.
Thus, presentism is true. (For the classic statement of the
"thank goodness that's over" argument, in favor of A
theories of time, see A.N. Prior 1959. The wider literature is
voluminous. Representative recent works include: Suhler &
Callender 2012; Hoerl 2015; Pearson 2018.)



There are different examples that draw upon our experience of pain and
our attitude towards it. Consider again a past headache and compare it
to a (possible) future headache, something that may result from
overenthusiastic behavior in the bar this evening. A future headache
is something that worries us. It influences our behavior. We seek to
avoid it. We may even fear it. By contrast, we feel differently about
past headaches (and past pains, generally). We don't fear past
pains. They don't worry us in quite the same way. One
explanation for this is that a past pain doesn't exist. Whilst a
future pain doesn't exist either, we know that it will exist if
we behave in such-and-such a way. It's the potential for that
headache to exist (to come into being) that causes us to modify our
behavior. We wish to avoid that state. But if we think that past and
future things exist, we cannot appeal to the explanation just given,
for if the past headache exists, presumably we should fear it or worry
about it, just as we should if a future headache exists. (For a brief,
general discussion of connections between time and rationality, see
the entry on
 time:
 SS12. For further reading on 'time biases' --
such as 'future bias', where an agent prefers that bad or
painful experiences be in the past and that good or pleasurable
experiences be in the future -- see, e.g., Hare 2007, 2013;
Sullivan 2017, 2018; Bnefsi 2020; Fernandes 2021.)



Last, but not least, we might motivate presentism by appealing to
ontological parsimony (e.g., Bourne 2006: 68-69). Suppose that
we endorse something like "Ockham's razor",
*viz*. the principle that one shouldn't multiply entities
beyond necessity (see the entry on
  simplicity>,
 esp. SS2). By asserting that only present things exist, i.e., by
not positing the existence of any non-present things, the
presentist's ontology is more parsimonious than the ontology of
their opponents (e.g., growing block theorists posit the existence of
past and present things, eternalists posit the existence of past,
present, and future things, etc.). All things being equal, we have at
least a defeasible preference for presentism over its rivals, if we
have a taste for ontological desert landscapes.



There are a number of complications with this way of motivating
presentism. For one thing, although it's typical (in
metaphysics) to see appeals to ontological parsimony in cases where
one view is more "*qualitatively*" parsimonious
than its rivals, that is, cases where a view posits fewer
*kinds* of thing than opposing views, it's far less
typical to see appeals in cases where one view is merely more
"*quantitatively*" parsimonious than rivals, that
is, cases where a view posits fewer things than another. The fact that
appeals to quantitative parsimony are less typical reflects a general
attitude that the only ontological parsimony that one ought to respect
is qualitative parsimony. As David Lewis famously puts it:



> 
> 
> I subscribe to the general view that qualitative parsimony is good in
> a philosophical or empirical hypothesis; but I recognize no
> presumption whatever in favor of quantitative parsimony (1973: 87)
> 
> 
> 



Now, it seems that if presentism is to be motivated by appeal to
parsimony, then it must be motivated by appeal to considerations of
*quantitative* parsimony. Presentism and eternalism don't
disagree about the *kinds* of things that exist. Both
presentists and non-presentists tend to agree on the metaphysical
kinds (or "ontological categories") that exist. What they
disagree about is the temporal location of the things that exist.
Presentism states that everything exists at the present time;
eternalism states that there are things that exist at other times. If
presentism is to be motivated in this way, then we must justify a
preference for quantitative parsimony in this case in the face of the
orthodoxy that Lewis expresses. (See Tallant 2013 for an attempt to
deliver this sort of argument for presentism. For arguments that
justify quantitative parsimony as a theoretical virtue, more
generally, see Nolan 1997; Baker 2003; Jansson & Tallant
2017.)



At the outset, we noted that presentism has been formulated,
developed, and modified in response to a range of objections. In what
remains of this entry, we consider what we take to be the most
prominent and well-developed of these objections and explain how
presentists have tried to respond (SSSS3-8).


## 3. Definitional Concerns



Consider the following minimal statement of presentism, *viz*.
the ontological thesis, **P**:


* (**P**)
Only present things exist.



There is a concern with **P**, understood as a statement
of presentism, arguing that the use of the verb "exist" is
ambiguous in a problematic way. The idea is that, once
**P** is disambiguated properly, presentism is either
trivially true (but consistent with some non-presentist views) or else
false. **P** admits of three apparently distinct
readings:


* (**P1**)
Only present things exist now.
* (**P2**)
Only present things have existed, exist now, or will
exist.
* (**P3**)
Only present things exist
*simpliciter*.



The highlighted portions indicate a putative disambiguation of
"exist". Opponents insist that these are the only
available readings of **P** and press the following
argument:


* (1) Presentism is
**P1**, **P2**, or
**P3**.
* (2) The claim
"only present things exist now"
(**P1**) is trivial.
* (3) The claim
"only present things have existed, exist now, or will
exist" (**P2**) is false
* (4) The claim
"only present things exist *simpliciter*"
(**P3**) is false.
* (5) Therefore,
presentism is either trivial or false.



For statements of this argument, see Crisp (2004: 17) and Ludlow
(2004: 22). For discussion of the (so-called) "sceptical"
challenge, in a variety of forms, see Merricks (1995: 523, 1999:
421-2), Zimmerman (1998: 209-10), Lombard (1999:
254-5, 2010), Sider (1999: 325-7, 2006), Callender (2000:
S588-90), Rea (2003), Meyer (2005, 2013), Savitt (2006),
Stoneham (2009), Mozersky (2011: 122-5), Torrengo (2012, 2016),
Miller (2013: 348-51), Tallant (2014), Deng (2018), and Deasy
(2019b), amongst others.



The argument (1)-(5) is valid. But why think that it's
sound? Well, premise (2) is clearly true. The claim that "only
present things exist now" amounts to the claim that "only
presently existing things presently exist". Whilst we
shouldn't disagree with this claim, it's a mere triviality
and cannot be used to advance a distinctive position in the philosophy
of time. Moreover, **P1** is consistent with
the existence of non-present things, contrary to the spirit of
presentism. For example, Marie Curie isn't a present
entity--she doesn't exist now--but she can exist (in
the past) without contradicting **P1**. Hence,
**P1** isn't an adequate statement of
presentism, regardless of its status as a truism.



What about premises (3) and (4)? The standard justification for (3) is
that **P2** is false because it's open
to counterexamples. The standard justification for (4) is that
**P3** collapses into
**P2**. Both are controversial. We take each
in turn.


### 3.1 Counterexamples to P2



The claim that we explore here is that: "only present things
have existed, exist now, or will exist"
(**P2**) is false because some non-present
things have existed. For example, Marie Curie isn't a present
thing, but she has existed. This appears to be a counterexample to
**P2**.



One might reply here that **P2** isn't
false (for the reason just given) because there *are* no
non-present entities--presentists don't think that there
*is* something, Curie, that exists and isn't present. To
work through the details here, it's important to start talking
about what presentists accept in the domain of their most unrestricted
quantifiers. That is, **P2** isn't false
because there are no non-present entities in the relevant domain of
quantification. Suppose that we read **P2** in
the following way: "for any *x*, if *x* has
existed, exists now, or will exist, then *x* is present".
And, following Thomas Crisp (2004), presentists may read the
quantifier "for any..." as "for any...
within time" (depending on views about the existence of timeless
entities). If we shift to this reading, it's no longer obvious
that **P2** is false. It's true that
there once was an entity, Marie Curie, who doesn't exist at all
anymore. But it's not clear that Curie must be within the
relevant domain of quantification simply in virtue of having once
existed. So, if we read **P2** as "for
any *x* (within time), if *x* has existed, exists now,
or will exist, then *x* is present"--and we deny
that there are any non-present entities--then
**P2** isn't false (Crisp 2004:
18-20). And, if **P2** isn't
false, then premise (3) *is* false, and the argument is
unsound.



Of course, whether one thinks that this kind of strategy is successful
will likely depend upon how one understands the locution "for
any *x*". Not everyone will be persuaded. For instance,
Ulrich Meyer (2005: 214, 2013: 68-69), when advancing his own
"sceptical" challenge to presentism, considers a statement
of presentism that's very similar to the reading of
**P2** offered by Crisp (2004), in which the
statement of presentism is equivalent to the claim that "only
present entities exist temporally". (On the assumption that
"*x* exists within time" and "*x*
exists temporally" are the very same notion, the two statements
are equivalent.) However, Meyer argues that it's clear enough
that Curie exists temporally. After all, she has existed! And what can
"*x* exists temporally" (or "*x*
exists") mean if not, simply, "*x* has existed,
exists now, or will exist"?


### 3.2 The Collapse of P3



Assuming that the likes of Meyer are correct (and that the likes of
Crisp are not), what should we make of premise (4)? What should we
make of the claim that: "only present entities exist
*simpliciter*" (**P3**) is false
because **P3** collapses into
**P2** (and **P2** is
false)? Perhaps we can argue that **P3**
doesn't collapse into **P2**, and that
**P3** represents a distinct way to state the
presentist's ontic thesis. A defender of
**P3** might argue that there's a notion
of "existence *simpliciter*" that's
intelligible, substantive and, importantly, distinct from the
"tensed" ("temporal") notion of existence
that's captured in **P2** (i.e.,
"has existed, exists now, or will exist").



Once again, there's clear and sustained disagreement about the
effectiveness of this strategy. Suppose that we can insist sensibly
that there's a notion of "existence
*simpliciter*" that helps presentism to avoid the
challenge that **P3** collapses into
**P2**. (If this is so, then our opponent
can't tell us, simply, that **P3** is
false if **P2** is false.) Nevertheless, this
raises the question as to what, precisely, is meant by
"*x* exists *simpliciter*" and whether the
new notion can be used to characterize presentism.



What does "*x* exists *simpliciter*" mean?
In this context, Meyer (2005: 214-5) tells us that if *x*
exists *simpliciter*, then *x* exists either in the
actual world, @, or else in some merely possible world. And, if
*x* exists in @, then it exists *in time*, it exists
*temporally*; *x* either has existed, exists now, or
will exist. Thus, it seems that if we specify the meaning of
"*x* exists *simpliciter*", we must take it
to mean either that *x* exists "outside time", but
somehow still in @, or else at some other world. But, perhaps
controversially, Meyer (2005: 215) argues that neither of these ways
of specifying the notion of "existence
*simpliciter*" will give us a characterization of
presentism, *qua* model of time. Presentism is a view about
what exists in time; it's not a thesis about what exists outside
of time, nor is it a thesis about what exists at other possible
worlds. (Recall, from the discussion of the implications of
**PA**, above, that nothing exists outside time, for
presentists; nothing exists that isn't present. Hence,
presentism concerns what exists *within time* since it implies
that nothing exists without.)



It's only fair to conclude this part of the discussion by noting
that it's unclear how far we should be moved by these
considerations. For instance, Daniel Deasy (2017) is clear that he
thinks very little of this objection. Deasy discusses the objection
(to presentism, defined as "always, everything is
present"), somewhat witheringly, as follows:



> 
> 
> [Some argue along the following lines:] the quantifier in the
> traditional definition is either tensed or tenseless. If it is tensed
> then presentism is the obviously false thesis that always, everything
> is now present. If it is tenseless then presentism is the trivially
> true thesis that always, everything is, was, or will be present.
> ... The problem with this argument is that the key
> premise--that the quantifier in the traditional definition is
> either tensed or tenseless--is false. The universal quantifier in
> the traditional definition ("everything") should be read
> as expressing exactly the universal quantifier of classical
> first-order predicate logic ... [The] traditional definition is
> intended to express a metaphysical thesis, and metaphysical theses
> ought to be expressed in the most metaphysically
> perspicuous--i.e., most "joint carving"--terms
> possible. Classical first-order predicate logic is a much better
> candidate for a language whose terms so cut than a natural language
> like English. Moreover, the standard quantifiers of classical
> first-order predicate logic are neither "tensed" nor
> "tenseless" (or at least, not in the sense of the above
> argument). ... [Quantifiers] are not verbs, they are quantifiers
> ... Therefore there is no good reason to think the quantifiers
> have either reading. (2017: 380-1)
> 
> 
> 



However, presentists shouldn't celebrate too early. They should
remain cautious. Deasy goes on to raise an independent concern with
how to define presentism. Echoing a challenge from Timothy Williamson
(2013: 24-25), Deasy objects that there's no satisfactory
way to spell out what's meant by "is present" in the
definition of presentism. Further, we may also need to say something
about the duration of the present (see Gentry 2021).


### 3.3 Existence Presentism



As we've seen, standard ways of characterizing presentism face
definitional worries. So, let's change tack for a moment.
Typically, presentism is presented as the view that only present
things exist. But it might seem natural to suppose that there's
more to presentism than a claim about the extent of our ontological
commitments. That is, presentism shouldn't just be seen as a
list of which objects exist (the present ones), but a claim about
existence itself. For instance, Dean Zimmerman (1996) characterizes
presentism as the view that "to be present *just is* to
be real or to exist" (1996: 117). When presentism is
characterized in this way, we can label it "Existence
Presentism", following Jonathan Tallant (2014).



Trenton Merricks gives a more thorough expression of this picture, as
follows:



> 
> 
> [Standard] definitions, even though they get at something important,
> fail to get at what separates presentism most fundamentally from
> eternalism. ... [Presentism] and eternalism differ most
> fundamentally with respect to the nature of time and, relatedly, with
> respect to what it is to exist at a time (and to have properties at a
> time). (2007: 119-20)
> 
> 
> 
> Presentists and eternalists alike say that those things that exist at
> the present time really do exist and, moreover, that properties had at
> the present time really are had. Thus one might think that, while
> presentism and eternalism part ways with respect to other times, they
> agree about the nature of the present time and, relatedly, agree about
> what it is to exist (and have properties) at the present time. But
> they do not agree about these things. Indeed, their differences with
> respect to the nature of, and existence at, the present time are as
> important as their differences with respect to the past and the
> future. (2007: 123)
> 
> 
> 
> [Presentists] insist that there are objects that *exist at the
> present time* (or, equivalently, that *presently exist*).
> Since they do not believe in a region called the "present
> time", presentists cannot reduce *existing at the present
> time* to being located at that region. I think presentists should,
> instead, say that *existing at the present time* just is
> *existing*. Thus, given presentism, if something exists, then,
> obviously enough, it exists at the present time. So, given presentism,
> since everything exists, everything exists at the present time. (2007:
> 125)
> 
> 
> 



This way of characterizing presentism challenges the orthodoxy
(sketched in
 SS1),
 which takes the main difference between presentism and eternalism
(etc.) to be their distinct ontological commitments. On this revised
way of thinking, such ontological disagreements are a consequence of
the view, rather than what's truly distinctive about it.
Instead, what's crucial to presentism is a claim about the
nature of existence. To exist *is* to be present.



How, if at all, does this way of thinking about presentism help with
the definitional worries? This move might help us to identify a new
kind of disagreement between presentists and non-presentists.
Presentists can endorse an identity claim, "existing at the
present time is existing" and, thus, draw new battlelines. This
identity claim is present-tensed and true *now*; it
doesn't face the same worries as the other statements of
presentism (**P1**,
**P2**, or **P3**).
Nonetheless, the claim is distinctive; it's not something to
which eternalists can assent. Eternalists don't agree that
existing now *is* existing.c


### 3.4 Transientism and Permanentism



A different sort of response to definitional worries is to recast the
debate between presentists and non-presentists as a debate concerning
two distinct, opposing theses: *transientism* and
*permanentism*. Whereas presentism and eternalism are views
about what exists, transientism and permanentism are views about
whether things begin or cease to exist. Transientism is the view that:
sometimes, something begins to exist and, sometimes, something ceases
to exist; permanentism is the view that: always, everything always
exists (Deasy 2015, 2017, 2019a; Cameron 2016; cf. Sullivan 2012).



One suggestion is that, if we accept that the traditional
presentism-eternalism debate is flawed because of definitional
worries, then the traditional debate should "give way" to
the new transientism-permanentism debate (e.g., Williamson 2013: 25;
Deasy 2019a: 284). A related suggestion is that, since mainstream
characterisations of presentism, eternalism, etc., should be rejected
(again, because of definitional worries), we should accept new
characterisations of these views, given in terms of transientism or
permanentism (e.g., Deasy 2017). On this approach, we might
characterise presentism as the conjunction of transientism and a
minimal conception of the A theory, i.e., that there is an absolute,
objective present moment (see Deasy 2017: 391; cf. Correia &
Rosenkranz 2015, 2020; Viebahn 2020).


## 4. Cross-Temporal Relations



*Prima facie*, there are myriad "cross-temporal"
relations. We admire Marie Curie; admiration is a
relation. Yesterday's rain caused today's flood; causation
is a relation. There are other kinds of relation, which we discuss
below, such as directly referring and truth-making, which seem like
they cross times (and as if they might cause special trouble for
presentism). For now though we want to consider the point very
generally. Presentism is not compatible with the existence of Marie
Curie or yesterday's rainfall; presentism denies the existence
of all past entities. Nonetheless, what we have here with admiration
and causation seems to be a relation. It's very natural and very
reasonable to suppose that a relation can only be instantiated if all
of its relata exist: *x* cannot stand in a relation R
to *y* unless both *x* and y exist. If that's
right, then there's an obvious worry. Presentism seems flat out
incompatible with the existence of any and all cross-temporal
relations. Something must give.



A famous statement of this "argument from relations" is
due to John Bigelow (1996). It goes as follows:



> 
> 
> ...in order for a relation to hold between two things, both of
> those two things will have to exist. Call this the principle that all
> relations are existence entailing. Add as a further premise the
> supposition that relations sometimes hold between a present thing and
> something else which is not present. The conclusion follows
> ineluctably, that some things exist which are not present. (1996:
> 37)
> 
> 
> 



Bigelow suggests that this argument goes as far back as the Stoics and
Epicureans. Here we focus on contemporary iterations of the problem.
For recent discussion of the problem, in a variety of forms, see Adams
(1986: 321-8), Quine (1987: 197-8), Chisholm (1990a,b),
Bigelow (1996), Sider (1999, 2001: 25-35), Craig (2000:
211-2), Davidson (2003), Markosian (2004), Crisp (2005),
Brogaard (2006, 2013), De Clercq (2006), Torrengo (2006, 2010), Inman
(2012), Ciuni & Torrengo (2013), and Ingthorsson (2019). For a
substantial, book-length treatment of the issue, see Torrengo
(2008).



Quite generally, presentism can be defended via one of a few
strategies to address this worry about "cross-time"
relations. One option: to use presently existing entities to make
sense of the relational claims. With our admiration of Marie Curie,
for example, this amounts to saying that: when she existed, Curie
instantiated various features and properties, those properties still
exist, and it's those present properties that we're
related to in admiration. Thus, it's not Curie herself that we
admire, but her perseverance, insight and brilliance. Of course, one
important issue with this strategy is that it fails to respect the
idea that it's Curie herself that we admire, rather than mere
properties that she exemplified. Alternatively, then, alongside
defending presentism we might deny that some or all relations are
"existence-entailing". Thus, we can stand in the relation
of admiration to Marie Curie herself, even though there's no
such entity as Curie. But here we would face the difficult task of
denying the natural and reasonable supposition that a relation can
only be instantiated if all of its relata exist. Presentists who go
this route deny "serious presentism" and start down the
road towards Meinongianism, a position which many find quite
undesirable (see the entry on
 nonexistent objects,
 esp. SS4). Serious presentism is the temporal analogue of
"serious actualism", the view that "necessarily, if
*x* has *F* or bears *R*, then *x*
exists" (see the entry on the
 possibilism-actualism debate,
 esp. SS4.1). (We remain neutral on the question of whether
presentism implies serious presentism, *pace* Bergmann 1999,
Davidson 2000, and leave the "non-serious" option open to
presentists.) There's at least one more option open: to say that
such seeming cases of relations aren't, in fact, relational at
all. Thus, rather than our admiration of Curie being a state that
consists in Curie existing, our existing, and our bearing a relation
to Curie, all that there is to such a state is our existing and
instantiating a monadic property, *admiring Marie Curie*. Since
the property is monadic, its instantiation requires only our
existence.



Unsurprisingly, there are questions about the advisability of each
strategy, in general, as well as about whether each can be pursued or
applied sensibly in defense of presentism. Nonetheless, with the above
general overview in hand, we now turn our attention to two
philosophical problems that confront presentism: the problem of
reference to non-present entities (SS5) and the
"truth-maker" problem (SS6). Both are specific
instances of our main objection, introduced above, and both present
special problems for presentists. (The well-informed reader will note
that we haven't yet mentioned explicitly problems concerning
quantification across times or metric tensed statements. We consider
both as part of
 SS6.)


## 5. Reference and Propositions



Note that Socrates was a wise, snub-nosed philosopher, who happened to
be Plato's finest teacher. From this story, we can infer that
"Socrates was wise" is true and, we might reasonably
suppose, it expresses a (true) proposition, <Socrates was wise>.
Similarly, we can take it that "Plato's finest teacher was
wise" is also true and it expresses a (true) proposition,
*<*Plato's finest teacher was wise>. [See the entry
on
 propositions.]



Some preliminary observations. Both propositions exist; they are true
and so they must exist in order to be true. (Assuming something like
"serious actualism", see above.) Equally, both
propositions are about the very same individual, Socrates, though
there's a sense in which <Socrates was wise> is about
Socrates more thoroughly (more intimately) than <Plato's
finest teacher was wise> is about him. Indeed, it seems that
<Socrates was wise> is "directly" about Socrates,
whereas <Plato's finest teacher was wise> is only
"indirectly" about him. <Socrates was wise> cannot
fail to be about Socrates; it determines Socrates, the same
individual, in all possible contexts. But, by contrast,
<Plato's finest teacher was wise> is about Socrates only
accidentally, only in virtue of the contingent fact that Socrates was
Plato's finest teacher.



Further, note that the sentence "Socrates was wise", which
expresses <Socrates was wise>, contains a proper name
("Socrates"). And, suppose that this directly refers to
Socrates. By contrast, "Plato's finest teacher was
wise", which expresses <Plato's finest teacher was
wise>, contains a description ("Plato's finest
teacher"). We might suppose that this doesn't directly
refer to Socrates, nor does it determine him in all possible contexts.
Consider, for example, the possible scenario in which Socrates never
encountered Plato. In this context, Plato's finest teacher would
have been a distinct individual and the corresponding description
"Plato's finest teacher" would pick out that
individual. As such, <Plato's finest teacher was wise>
would not be about Socrates and the truth of the proposition
wouldn't depend upon any facts about him. What unites both cases
is reference; what divides them is the direct or indirect character of
how the expressions refer. Typically, reference is construed as a
relation that obtains between language and reality (between linguistic
items and things in the world). [See the entry on
 reference.]
 And, again: for two things to be so related, both things (both
relata) must exist.



In defending presentism, we face a problem of direct reference with
respect to merely past entities. (Although, on one reading, it's
merely an instance of the problem of "cross-time
relations" introduced in
 SS4.)
 It seems that we can and do refer successfully to entities that have
existed and exist no longer, entities that don't exist at all,
given presentism. But, if this is so, then the past entities that we
refer to (and which are related to our linguistic items) must exist,
contrary to presentism. Presentists face a difficult choice. That is,
they must reject one of the following four claims, which form an
apparently inconsistent set: (i) we successfully refer to merely past
entities, (ii) reference is a relation, (iii) for a relation to
obtain, the relata must exist, and (iv) there are no merely past
entities (i.e., past entities don't exist). Presentists
can't deny (iv), since that amounts to a rejection of
presentism. But it proves almost equally difficult to reject any of
the other claims, given their independent plausibility.


### 5.1 Singular Propositions



Let's move away from the issue of reference and turn to the
metaphysics of propositions. First, note that <Socrates was
wise> is a "singular" proposition: a proposition
that's directly about some individual, Socrates, whereas
<Plato's finest teacher was wise> is a
"particularised" proposition: a proposition that's
about Socrates, but not directly about them. [See the entry on
 singular propositions.]
 Frequently, propositions are taken to be complex metaphysical
entities, entities with constituents and structure. [See the entry on
 structured propositions.]
 On this way of thinking, singular propositions are understood
typically as constituted by individuals, specifically the individuals
that they are (directly) about. Hence, a singular proposition about
some, *x*, is constituted by *x* itself. By contrast,
particularised propositions aren't constituted by individuals,
although they are structured entities with constituents. A
particularised proposition about *x* isn't constituted by
*x*, but may be constituted by a property of *x*. On
this view, <Socrates was wise>, for example, is constituted by
Socrates himself, whereas <Plato's finest teacher was
wise> isn't constituted by Socrates--but, perhaps, the
proposition is constituted by some actual accidental property of
Socrates, *being the finest teacher of Plato* or, indeed,
*having been the finest teacher of Plato*. This way of thinking
about (singular) propositions isn't universal, but it's
part of a standard theory with many adherents (see Adams 1986;
Williamson 2002; King 2007). In what follows, we refer to this view as
the 'neo-Russellian' view of propositions.



If propositions are complex (structured) entities with constituents,
then they depend for their existence upon the existence of their
propositional constituents. The way that such entities ontologically
depend upon constituents is analogous to the way that sets depend upon
their members. Consider, for example, {*x*}, *x*'s
singleton set. {*x*} depends upon *x* for its existence.
Typically, this is cashed out as follows: necessarily, {*x*}
exists only if *x* exists; and, it's not the case that
*x* exists only if {*x*} exists. Similarly, we say:
necessarily, some proposition *P* exists only if its
(propositional) constituent *c* exist; and, it's not the
case that *c* exists only if *P* exists. [See the entry
on
 ontological dependence.]



Presentism faces a problem about how to account for the existence of
singular propositions about past entities. It seems that there are
such propositions; recall that "Socrates was wise"
expresses a true singular proposition, <Socrates was wise>,
which must exist in order to be true. The problem arises given the
following treatment of singular propositions: a proposition
that's directly about an individual *x* is constituted by
*x* itself, and propositions depend for their existence upon
the existence of their constituents. So, for example, <Socrates was
wise> is constituted by Socrates himself and this proposition
ontologically depends upon Socrates.



Here's a deductively valid argument against presentism, based on
the above considerations:


* (1) If a proposition is
true, then it exists.
* (2) <Socrates was
wise> is true.
* (3) <Socrates was
wise> exists. (1, 2)
* (4) If a proposition
exists and has constituents, then its constituents exist.
* (5) Socrates is a
constituent of <Socrates was wise>.
* (6) Socrates exists.
(3, 4, 5)
* (7) If Socrates exists,
then presentism is false.
* (8) Presentism is
false. (6, 7)



The argument is clearly valid. To defend presentism, we must deny one
of the premises. But each premise appears independently plausible. (1)
takes truth to be a monadic property, e.g., *being true*, and
reflects a commitment to serious actualism: if *P* instantiates
*being true*, then *P* exists. (2) takes propositions as
truth-bearers (or "truth-value bearers") and follows from
the simple claim that there are truths about the past (more on this in
 SS6).
 (4) takes propositions as complex entities and reflects a commitment
to the principle that a complex depends for its existence upon things
that constitute it. The remaining premises, (5) and (7), follow
straightforwardly from the two metaphysical theses at issue, the
neo-Russellian view of propositions and presentism, respectively.



The most obvious line of response (if we wish to avoid rejecting too
many plausible premises) is to deny some aspect of the
neo-Russellian view of propositions. Here we see at least two
sorts of reply: some suggest a modification of the view (e.g.,
Ingram 2019: 85-104), others suggest a total rejection of
it (e.g., Merricks 2012, 2015: 157-90). If we take the way
of modification, we can accept that propositions are structured
entities with constituents, but urge that the propositional
constituents are presently existing entities, and not any non-existent
past entities. If we take the way of rejection, we can deny that
propositions are structured entities and, instead, suggest a distinct
treatment of propositions.



For another line of response, presentism might be modified
*a la* Williamson (1998, 2002), who defends a view
according to which past objects still exist, but are no longer
concrete. We don't take a stand on whether such a position
deserves the epithet "presentism" and, further, we note
that Williamson (2013: 20) explicitly states that he would prefer to
see the presentism-eternalist debate recast in other terms, using a
different methodology (see SS3.4). Nonetheless, it is clear enough
that if the existence of abstract-Socrates (who once was concrete but
now is abstract) is compatible with presentism, then this would give
the presentist a means to deny (7) and reject the argument given
above.



For discussion of the above problem, in a variety of forms (i.e.,
concerning direct reference or singular propositions), see Adams
(1986: 315-22), Fitch (1994), Markosian (2004), Merricks (2012:
64-67, 2015: 170-3), and Ingram (2016). There's a
modal analogue of this problem, facing actualism (roughly, the view
that "only actual things exist"), and a rich literature
accompanying it. For discussion of this problem, see Adams (1981),
Plantinga (1983), Barcan Marcus (1985), Fine (1985), Davidson (2000),
Merricks (2012: 64-71, 2015: 173-80), and Speaks
(2012).


## 6. Truth and Truth-Making



A good deal of work on presentism in the philosophy of time concerns
itself with truth. In the current context, the work in question
focuses on whether (and, if so, how) presentism can account for the
different kinds of true proposition that we endorse. Our primary focus
will be on how to defend presentism whilst giving appropriate
ontological explanations for the truth of true claims about past
things (with the "truth-making" literature as the
background). We also briefly address a related problem of truths about
spans of time, which is sometimes treated as a separate issue
concerning quantification over times.



We turn to one of the most discussed challenges to presentism in the
contemporary debate: the truth-maker objection to presentism. At first
pass, this objection is another instance of the general problem of
cross-temporal relations
 (SS4),
 but there are reasons for thinking that concerns about truth-makers
underwrite a special problem for presentists. This objection is
treated as a significant problem for presentism by many, including but
not limited to: Sider (2001: 35-42), Armstrong (2004:
145-50), Keller (2004), Crisp (2007), Cameron (2011), Sanson
& Caplan (2010), Markosian (2013), Tallant & Ingram (2015),
and Emery (2020). For one general discussion of the problem, see
Caplan & Sanson (2011). [See the entry on
 truthmakers
 for background.]



The truth-maker objection is presented as a tension between three
independently plausible principles: (i) presentism, (ii) that there
are (evidence-transcendent and objective) truths about the past, and
(iii) truth-maker theory, the view that truths about the past are
"*made true*" by some existent (see, e.g., Keller
2004: 85-87; Cameron 2011: 55-57; Tallant & Ingram
2015: 355, for this mode of presentation). Obviously, we cannot defend
presentism and abandon (i). Further, rejecting (ii) seems a steep
price to pay (cf. Dawson 2021; Miller forthcoming). If there are no
truths about the past, then it's hard to make sense of the idea
that things change from moment to moment (or that time passes; see
 SS7).
 That leaves us with (iii). Here, three options present themselves:
locate the required truth-makers, deny that truths about the past
require truth-makers, or argue that truth-making isn't the kind
of relation that requires the existence of both relata. We consider
these options in turn.



Note that a version of this problem can be stated with the principle
that "truth supervenes upon being" in place of truth-maker
theory (as in Kierland & Monton 2007). It's far more common
to raise this objection as a problem about a lack of truth-makers
(rather than the lack of an appropriate "subvenient
base"). Hence, we focus on the truth-maker objection.


### 6.1 Locate the Truth-Makers



Truth-makers for truths about the past aren't easy to find. We
are searching for entities "*in virtue of*" which
propositions about the past are true. For example, <Curie
existed> is true *in virtue of* some entity, its
"truth-maker". But what plays the truth-making role?
Schematically, two kinds of solution can be given here: (i) posit
presently existing truth-makers, or (ii) posit truth-makers that exist
"outside time". Option (ii) is open to presentists who
countenance the existence of some *atemporal* entities (e.g.,
propositions, numbers, etc.), though such a version of presentism
would require a defense of the idea that entities that exist
*outside* of time do no violence to the claim that "only
present things exist"
 (SS1).



Presentism can be amended via the addition of *atemporal*
truth-makers--truth-making entities that are, in a sense,
"outside" time (see Bourne 2006; Crisp 2007). This is
"ersatz presentism". Ersatz presentists claim that, e.g.,
<Curie existed> is "made true" by an abstract time
that represents how things were when Curie existed. (This is an
"ersatz" time, rather than a "genuine"
concrete time.) One way to understand ersatz presentism is as the view
that there's an abstract four-dimensional manifold of times that
represents how things were, are now, and will be. This manifold is
ordered by an ersatz B-theoretic "earlier than" relation
and forms an ersatz B series of times. The truth-makers for truths
about the past are abstracta: the ersatz times. An ersatz time,
*T*, represents how things *were* (at some past time) by
some other ersatz time, *T\**, accurately representing how the
concrete world *is now*, and by *T* bearing the
"earlier than" relation (the "ersatz
B-relation") to *T\**.



Ersatz presentism is popular, but option (i)--positing present
truth-makers--includes more variation. The most well-known
version of this view is "Lucretianism" espoused by John
Bigelow (1996). Lucretians claim that <Curie existed> is made
true by the world now instantiating a primitive past-tensed property
(a "Lucretian" property) of having contained Marie Curie.
The presently existing truth-maker is the present instantiation of the
Lucretian property (*having contained Curie*) by the world.
There are a range of other "property solutions", alongside
Lucretianism, which differ in important respects, but which share a
common core. For instance: see Keller (2004: 94-101) on a range
of solutions, including one with indestructible atoms and their
properties, Cameron (2011, 2013) on temporal distributional
properties, McKinnon & Bigelow (2012) on tensing the instantiation
tie, and Ingram (2018) on uninstantiated thisnesses, amongst
others.



Responses to positions that posit present truth-makers (i.e.,
Bigelow's Lucretianism and "Bigelow-style" property
solutions, mentioned briefly) are that each suffers from three
problems, perhaps only one of which afflicts the ersatzer's
proposal. The problems facing presentism supplemented with these
truth-makers are as follows.



First, note that any solution must ensure that the truth-makers
deliver the "right results" with respect to what's
true about the past. To illustrate, consider the following natural
progression of an object through time. Our story begins with a green
banana. Time passes; the banana ripens. The banana is now yellow, but
it was green. The world now instantiates the property *having
contained a green banana* (so says the Lucretian). So far, so
good. But consider a progression where the banana ripens and yet the
world comes to instantiate a different Lucretian property. Suppose
that the world instantiates *having contained a red banana*
instead. This is problematic. In the scenario imagined, though it was
the case that the world contained a green banana, <There was a
green banana> is false; and, despite the world never having
contained a red banana, <There was a red banana> is true.
Although the problematic progression is deviant, the worry with
property solutions is that these kinds of progression appear
*possible*, given the advertised metaphysic. If such deviant
progressions are possible, we can object to these present entities
being the right kind of truth-makers for truths about the past (see
Tallant & Ingram 2012; Cameron 2013; Leininger 2015).



A second concern with "property solutions" stems from the
worry that the kind of properties involved, e.g., tensed
"Lucretian" properties, are wholly objectionable. Some
regard properties such as *having contained dinosaurs* as
"suspicious" or "dubious" entities--they
are objectionable entities that shouldn't be countenanced in a
respectable metaphysic. They are objectionable because, in a sense
that's difficult to pin down, they *point beyond* their
instances (their bearers). Thus, *having contained dinosaurs*
is a property that "points beyond" how the world *is
now*; it points beyond the intrinsic nature of its bearer, and
"points" to how the world *was*; namely, containing
dinosaurs. And, say the objectors, acceptable properties aren't
like that; respectable properties don't point beyond (see Sider
2001: 39-42; Crisp 2007: 93-98; Merricks 2007:
134-6; Cameron 2011: 58-62).



Another significant objection facing presentist attempts to solve the
truth-maker objection is based on "aboutness" intuitions
and their role in determining which entity (or entities) is an
adequate truth-maker for some truth. The idea goes as follows. A truth
(any truth) is about something. If a proposition is made true--if
a proposition "owes its truth" to something in the
world--then the thing in the world that makes the proposition
true should be what the truth is about (Merricks 2007: 28-34).
After all, <Taylor loves to sing> is about Taylor and her love
of singing. It would be altogether wrong for that proposition to be
made true by the existence of anything other than Taylor and her love
of singing. At least, so goes the thought.



However, all these "solutions" to the truth-maker
objection share a common feature: the past entities that propositions
about the past seem to be *about* don't exist, given
presentism. Marie Curie doesn't exist, yet <Curie existed>
*is* about Curie. There are no dinosaurs, yet <there were
dinosaurs> *is* about them. Our "aboutness"
intuitions tell us that propositions *about the past* should be
made true by past entities, but they simply cannot be, given
presentism. Whether the truth-makers we posit exist *now*, or
exist outside time, the kind of entities that we posit won't be
up to the task. If we respect the aboutness constraint (on truth-maker
theory), and cannot shake off this objection, we will likely be
inclined to give up on solving the objection by attempting to locate
the required truth-makers. (There are some exceptions. E.g., Ingram
2019 develops a Bigelow-style response and argues that the putative
truth-makers, uninstantiated thisnesses, do satisfy aboutness
intuitions.)


### 6.2 Deny the Need for Truth-Makers



Recall, the claims that generate the truth-maker objection: (i)
presentism, (ii) there are truths about the past, and (iii)
truth-maker theory. By locating truth-makers for truths about the
past, we attempt to reconcile all three claims. But another strategy
is to simply deny (iii), to assert that truths about the past
don't require truth-makers.



This way of approaching matters has been mooted (e.g., Tallant 2009b;
Ingthorsson 2017), but it hasn't received a huge amount of
support. This is due, at least in part, to the fact that it can be
viewed as a partial response. We can deny that truths about the past
require truth-makers, but we must go further to explain what to say
*instead* about their truth. Presumably something must be said,
if we hope to account for them. We can't say, simply, that
truths about the past require no truth-makers and then say nothing
more about what they require. And while we might look to replace
truth-maker theory with something less ontologically committing,
presentists haven't been forthcoming with an account of how
truths get to be true, if not by some kind of truth-making
account.


### 6.3 The Truth-Making Relation isn't Existence-Entailing



All of this leads us to the final option that we will consider here.
Namely, that the truth-maker relation isn't existence-entailing.
This kind of approach, described elsewhere as "nefarious"
(contrasted with the "upstanding" project of locating
truth-makers), uses the language of truth-making without positing
truth-makers for truths about the past. In presenting the nefarious
strategy, we can treat it as something like the union of two theses:
(1) truths about the past are expressed using primitive and
unanalysable tense operators, and (2) tense operators don't pick
out a distinctive ontological category or aspect of reality. This sort
of nefarious approach has been pursued recently by Tallant (2009a),
Sanson & Caplan (2010), and Baia (2012), amongst others. The
labels ("nefarious" and "upstanding") are due
to a recent discussion by Tallant & Ingram (2015).



To clarify: nefarious "cheats" (like Tallant) will say
"<It was the case that p> is true, because it was the case
that p". "Was" is primitive and unanalysable, and
those adopting this position will agree that "was"
doesn't pick out any ontology; it doesn't help us to speak
of a distinctive metaphysical category. To that extent, those in this
"nefarious" camp, will agree that there are truths about
the past, and will agree that how the world *was* makes true
how things are, but they deny that the ensuing truth-maker
"relation" (such as it is) between the past and the
present (i.e., the true propositions) is existence-entailing. For
some, that might simply be considered treacherous. How might
presentists motivate the nefarious position?



One key motivation involves a comparison with the
"upstanding" approaches
 (SS6.1)
 and the first problem we raised, *viz*. getting the
"right results". If we think that there are truth-makers,
then we must ensure that the truth-making entities get things right.
That is, if the world contained a green banana, then it had always
better be true, any time after the fact, that a truth-maker exists for
<There was a green banana> (rather than, say, a truth-maker for
<There was a red banana>, in the case where the world never
contained a red banana). But notice, then, that this seems to imply
some kind of "fixing" relation; how the world *was*
(containing a green banana, not containing a red banana) serves to
"fix" what truth-makers exist *now*.
"Fixing" is, plausibly, a relation. And, if *x*
fixes *y* then, intuitively, both *x* and *y*
must exist; both relata of the fixing relation should exist. But on
the presentist picture, that's unacceptable. Past things
don't exist. In that case, the required "fixing"
relation isn't existence-entailing; it doesn't require the
existence of both relata. And, if that's right, then presentists
may as well "cut out the middleman" (so to speak) and
treat the truth-making relation as
"non-existence-entailing" and avoid any ontological
inflation. Presentists don't require ontological commitment to
present truth-makers (ersatz times, Lucretian properties, etc.) for
truths about the past. They can do without. (See Ingram 2019:
179-92 for critical discussion.)



Is presentism out of the woods when it comes to the truth-maker
objection? It's unclear. For instance, we might retain the worry
that any relation must be existence-entailing and that what this shows
is that we should give up on presentism (see, e.g., Baron 2013). And,
even if we can solve the truth-maker objection, there's a
closely related concern that looks like it will raise further
problems. (We discuss the related concern in what remains of this
section.)


### 6.4 Truths about Spans of Time



It's true that there have been seven English Kings called
"Edward". Is presentism compatible with that claim? How
should we interpret the semantics? At no point in history were there
all seven Kings; the Edwards weren't contemporaneous. But, if
the Edwards didn't all exist together, then how can <There
have been 7 English Kings called "Edward"> be true?
Presentism faces a novel problem regarding truths about the past when
such truths concern "spans" of time (see Lewis 2004).
After all, the natural reading is false: it was the case that
"there are 7 English Kings called
'Edward'".



Two routes suggest themselves as plausible avenues to explore. The
first is to try to make sense of talk of spans by using talk of
individual times. Following the literature, call these "slice
operators". The idea, then, is that we say that



> 
> 
> It *WAS* the case that ["<There is a King called
> Edward>, and it *WAS* the case that [<There is a King
> called Edward>, and....]]"
> 
> 
> 



Somewhat loosely, we can describe this as analyzing the span in terms
of the individual "slices" that would make it up, were
such a thing as a "span" to exist.



There are many difficulties with this kind of approach. The most
obvious challenge is that, in the above, the second iteration of our
tense operator, "WAS" appears within the scope of the
first. Thus, the attempted paraphrase of <There have been 7 English
Kings called "Edward"> is a sentence of the form
"there has been a king called 'Edward', and there
had been a king called 'Edward'...". For one
thing, however, suppose that there have been infinitely many entities
in the past. Kings will not be a useful candidate here, so imagine
instead that there have been infinitely many electrons. Hence,
<There have been infinitely many electrons> is true. But this
requires a construction with an infinite number of nested quantifiers
and tense operators. This won't do, for no such construction can
be generated, despite the fact that we clearly *can* utter a
sentence that expresses the relevant proposition, "there have
been infinitely many electrons".



Another important problem for the translation approach is that there
seem to be cases in which the paraphrase is false and yet the
paraphrased sentence is true. Consider a merely possible case in which
some of the past Kings were instantaneous and simultaneous. (If this
is too implausible in the case of Kings, given facts about royal
succession, then swap the case for one involving physical particles
which can be instantaneous and simultaneous.)



The second route sees us endorsing a primitive "span"
operator, an operator that picks out temporal intervals rather than
individual moments (see Lewis 2004: 12). Rather than try to analyze
the span in terms of slices, this approach sees us just endorsing a
span operator as a primitive piece of terminology. Berit Brogaard
(2007) introduces this strategy neatly, as follows:



> 
> 
> Where the usual slice operators mean (as the eternalist would put it)
> "at some past (or future) moment", a span operator means
> "at some past (or future) interval" ([Lewis] 2004: 12).
> Thus, where "it HAS been that" is the past-tense span
> operator, Lewis suggests that we translate "there have been two
> kings named Charles" as "it HAS been that (there are two
> kings named Charles)". By eternalist lights, this means that
> "it is true of some interval in the past that there are two
> kings named Charles" ([Lewis] 2004: 12). The presentist, of
> course, cannot accept this translation, but must presumably treat span
> operators as primitives. (2007: 73)
> 
> 
> 



There are also problems with this route. First, it seems that such
span operators introduce ambiguities. Let's introduce the span
operator "HAS" as the operator "it has been the case
that..." and consider a target sentence, "first it
was raining and then the sun shone". Then, suppose that we
paraphrase this as: "HAS (it is raining and the sun is
shining)". This is problematically ambiguous. The paraphrase
might mean that there has been an interval of time throughout which it
has both been the case that the sun has shone and it has rained. Or,
it might mean that there is an interval of time, throughout a
sub-interval of which the sun shone and throughout another
sub-interval of which it rained. Clearly, we want the latter; but with
HAS, at least as stated, we have no means of differentiating the two.
If the semantics of the span operator are ambiguous, then it
doesn't give us a sensible semantics for span-talk (cf. Tallant
& Ingram 2020).



As should be clear, merely solving the truth-maker objection
doesn't automatically address this problem of spans. The
truth-maker objection rests upon the fact that presentists apparently
lack the ontological resources required to accommodate truth-making.
The span objection rests upon the fact that, given presentism, it is
far from clear how to provide an adequate regimentation of the
semantics of ordinary language. Bringing together an adequate
semantics as well as an adequate ontology is no easy task.


## 7. Temporal Passage



Next, we turn to an objection to presentism that concerns the idea
that time really passes. The challenge, put simply: presentism
isn't compatible with time's passage. This is a problem
since presentism is a view that requires that reality is
"dynamic" and that there is a change in what exists over
time, which is usually described in terms of the passage of time. (For
the purpose of this entry, we ignore general arguments to the
conclusion that time doesn't really pass and, instead, focus on
specific challenges to presentism.)



Why think that presentism isn't compatible with passage?
Typically, the passage of time is expressed in the following terms:
what's future approaches the present, becoming less future, and
what's past recedes from the present, becoming more past. Prima
facie, there's a problem. What's apparently required for
the truth of this passage metaphor is inconsistent with the view that
only present things exist. There are no future things, so nothing can
approach the present; nor are there past things, so nothing recedes
from the present. To defend presentism, we have to suggest another way
to interpret the claim that time really passes.



One way to reinterpret the claim is as follows: there's change
in what exists over time. Put another way: what's present
changes. But it's unclear whether this solves the problem or
shifts it down the road. What's required in order to account for
the claim that "what's present changes"? One might
reasonably suppose that to assert that what's present changes,
from one moment to the next, we require a difference in the character
of successive moments (see Leininger 2015). But there are no such
successive moments, given presentism. There's only the present
moment and its contents.



In defense of presentism, we might insist that what exists
*now* is sufficient to account for the difference in character
of successive present moments. Some of the strategies used in reply to
the truth-maker objection are useful here. Consider, e.g., ersatz
presentists who posit abstract times that represent how things were,
are, and will be, when a given time is present (when it's
"true") (see Markosian 2004; Bourne 2006; Crisp 2007).
Ersatz presentism has the resources to assert that things really
change (and so time really passes); there's a difference between
the character of successive moments, given the manifold of ersatz
times. How things are at the present time is different from how things
were (represented by an abstract time). Indeed, it seems that any
version of presentism that posits presently existing entities to
address worries about cross-time relations, for instance, or as
putative "ontological grounds" for truths about the past,
can use such entities to establish that there's a difference
between successive moments without reifying any non-present
things.



At this point, however, a new question arises. So understood,
presentism has the resources to ground time's passing at only
the present time. That is, everything required to establish that
things change from one moment to the next must be contained within a
single moment, the present. But within such a version of presentism,
what *guarantees* that things *really* change? Or, to
approach the same point differently, what in the metaphysics
guarantees that the present resources accurately reflect *how
things were*--e.g., why think that the ersatz manifold
accurately represents the past--when there's no connection
to the past? Why can't reality consist of a single
"frozen" slice of concrete time, along with the various
ersatz times? If reality is that way (what's concrete never
changes and we have nothing more than a frozen concrete instant
against the backdrop of many ersatz times), then we still have no
temporal passage. What the presentist must do is find some way of
insisting that reality cannot be such; reality cannot include but a
single concrete slice coupled to truth-makers for talk about the past
and future, where those truthmakers cannot be said to
*guarantee* that things *really change* (cf. the
discussion of how truth-makers get the "right results"
from
 SS6).


## 8. Relativistic Physics



In preceding sections, we examined problems facing presentism that
come from metaphysical quarters. In particular, we looked at a problem
of "cross-temporal relations"
 (SS4),
 and discussed two instances of that general problem, which pose
special problems for presentism (SSSS5-6), before
examining a related challenge concerning temporal passage. Now, though
there are many worries for presentism that come from metaphysics,
perhaps the most serious objection to presentism comes from physics.
In particular, the special theory of relativity ("STR")
has been presented as in direct tension with presentism. [See the
entry on
 being and becoming in modern physics.]



Simon Saunders (2002) gives us a clear picture of how things
supposedly stand with respect to presentism and STR, as follows:



> 
> 
> According to presentism, all that is physically real is the
> present--a system of physical events all of which are
> simultaneous with each other. No other events are real. Precisely what
> this system of events may be, now, as I snap my fingers, may not be
> known to me; but there is a fact of the matter as to what it is, and
> it is a universal fact which embraces us all. It is an intersubjective
> reality--now, as a snap my fingers--and it is a reality
> which contains us only as an incidental part. But even if one knew all
> that there is to know, consistent with special relativity, one would
> not be able to say what this system of events might be. According to
> presentism, therefore, special relativity is radically deficient as a
> description of reality. It is blind to the sequencing of what is
> physically real. (2002: 279-80)
> 
> 
> 



A quick and dirty reply on behalf of presentism is to suggest that
metaphysics and science are, in some sense, demarcated disciplines.
That is, the findings of physics are of no relevance to our best
metaphysics (and vice versa). But this doesn't seem to be a move
that we should make. Both metaphysicians and physicists are, surely,
trying to uncover the structure of the world and to theorize about the
nature of reality (fundamental or otherwise). To ignore one another is
no way for protagonists to carry on when both aim at the same basic
goal. Of course, this means that we must say something in reply to
Saunders and others, who raise the same sort of objection (e.g.,
Putnam 1967; Stein 1968, 1970; Savitt 1994, 2000; Sider 2001:
42-52; Wuthrich 2013; cf. Emery 2019, 2021). But what can
be said?



Katherine Hawley (2006) suggests two routes: "Undermining"
or "Counterargument" (we introduce each in turn). Suppose
that, as seems to be the case in the debate concerning STR, we want to
argue that some metaphysics, posited by science, is false. That is,
the science, as it's traditionally interpreted, delivers the
"wrong" metaphysics. There are options (though, as Hawley
notes, it seems likely that any genuine attempt to respond to the
objection from relativity may require a little of each). First,
"Undermining":



> 
> 
> This is the attempt to show that the scientific metaphysics is not
> involved in generating novel prediction, and thus that its appearance
> in a scientific theory does not give us reason to think it true.
> (2006: 463)
> 
> 
> 



As Hawley notes, there's a second step to Undermining, since
merely establishing that the metaphysics implied by the traditional
interpretation of a scientific hypothesis isn't essential to the
scientific theory, doesn't establish that the metaphysics with
which we would seek to replace the scientific metaphysics is
preferable. We need to do more than show that the metaphysics implied
by traditional interpretation and the metaphysics that we prefer are
on a par. We need to show that the
"metaphysically-supported" metaphysics is on a stronger
footing than the "scientifically-supported"
metaphysics.



Undermining is a strategy that a number of metaphysicians have
plausibly looked to deploy, arguing that there are empirically
equivalent theories that differ with respect to metaphysical
commitments, but yield the same predictions. For instance, see Craig
(2001) and Markosian (2004); Zimmerman (2011) explores a range of
options.



Consider a case: if a rod, *R*, is traveling in direction d and
is observed by an observer, *O*, who is stationary with respect
to *R*, then *R* will appear to be length *l*.
If, however, *O* is in motion with respect to *R*,
moving toward it, then the length of *R* will appear, to
*O*, to be less than *l*. There are two competing
explanations we might give, a standard "space-time"
interpretation, as well as a "neo-Lorentzian"
interpretation. (For philosophical defenders of the neo-Lorentzian
picture, see Tooley 1997 and Craig 2001.) As Balashov &
Janssen (2003) have it:



> 
> 
> ...the space-time interpretation and the neo-Lorentzian
> interpretation provide constructive theory explanations. In the
> space-time interpretation, the model is Minkowski space-time and
> length contraction is explained by showing that two observers who are
> in relative motion to one another and therefore use different sets of
> space-time axes disagree about which cross section of the
> "world-tube" of a physical system give the length of the
> system. In the neo-Lorentzian interpretation, length contraction is
> explained by a combination of dynamical effects of measurement. (2003:
> 331)
> 
> 
> 



Now, to endorse this "Undermining" approach, we would have
to say that the neo-Lorentzian account is preferable to the space-time
account. And, problematically, that looks to be false. The problem is
as follows. There's an explanatory advantage to treating length
contraction as explained by geometric features of space-time, rather
than by a dynamically occurring process. This, as we see below, will
require us to postulate an unexplained brute fact as to why length
contraction and time dilation appear in laws governing all matter.
Since unexplained coincidences, or treating certain facts as
"brute", is suboptimal (particularly when, as Balashov
& Janssen argue (2003: 341-2), the space-time interpretation
offers a better explanation--one that does not treat Lorentz
invariance as brute or mysterious), so we ought to deny the
neo-Lorentzian interpretation of relativity.



Let's try to get a better sense of this. What's the brute
fact required of us? And why should we worry about it? Why should we
think that the neo-Lorentzian theory, which is acknowledged to be
empirically equivalent to STR (Balashov & Janssen 2003: 23;
Callender 2008: 52-53), offers an inferior explanation of both
length contraction and time dilation than does STR? Janssen (2002)
puts the point as follows:



> 
> 
> For Einstein, the Lorentz-transformed quantities are the correctly
> measured real quantities. In the final version of Lorentz's
> theory, measurements never reveal the real quantities because all
> measurements are made with devices that are systematically distorted
> and improperly synchronized as a result of their and the
> observer's motion through the ether. (2002: 429)
> 
> 
> 



Thus, where for Lorentz, "Lorentz-invariance" is a product
of a law governing the dynamical behavior of entities in motion, for
Einstein, Lorentz-invariance is simply a product of the geometry of
space-time. As Balashov & Janssen go on to argue:



> 
> 
> Compare the status of Lorentz invariance in the two interpretations.
> In the former, Lorentz invariance reflects the structure of space-time
> posited by the theory. In the latter, Lorentz invariance is a property
> accidentally shared by all laws effectively governing systems in
> Newtonian space and time...In the neo-Lorentzian interpretation
> it is, in the final analysis, an unexplained coincidence that the laws
> effectively governing different sorts of matter all share the property
> of Lorentz invariance. (2003: 341)
> 
> 
> 



So, here's the detail of the objection. Lorentz's theory
was born of Newtonian mechanics and Maxwellian electrodynamics
(Janssen 2002: 423): the latter incorporated electric and magnetic
fields, but made no pronouncements at all concerning other forms of
matter. Thus, although we *can* extend the Lorentzian theory to
all laws governing matter, we have no reason to do so. It just happens
to turn out that the laws governing matter all instantiate this
property. Craig Callender (2008) makes the point clearly, as
follows:



> 
> 
> The matter fields are Lorentz invariant but the space-time is not. For
> this reason, all else being equal, one ought to prefer the Einstein
> Minkowski interpretation to the Lorentz interpretation. Positing
> otherwise unnecessary unobservable structure--absolute
> simultaneity--does violence to Ockham's razor. (2008:
> 53)
> 
> 
> 



Callender goes on to point out that once we grant that the Lorentz
interpretation is logically consistent and empirically adequate, the
question becomes, "[w]hat are a few lost explanatory virtues in
contrast to \_\_\_\_\_\_\_ (fill in the blank with whatever tenses
explain)?" (2008: 53). After all, we have to posit an
unobservable frame of reference and we don't, typically, posit
unobservables without good reason. At the moment, we lack good reason,
unless we think that the motivations for presentism (e.g., those
described in
 SS2)
 serve to persuade us that a neo-Lorentzian interpretation of the
physics of space-time is preferable to the space-time interpretation.
Undermining thus looks to be a difficult road to plough.



The second option that Hawley (2006) describes,
"Counterargument", is as follows:



> 
> 
> This alternative to Undermining accepts that the scientific
> metaphysics is genuinely confirmed by the role it plays in generating
> empirical success, but claims that independent reasons to believe the
> traditional metaphysics outweigh this scientific support. (2006:
> 464)
> 
> 
> 



Counterargument is bold in the extreme. It seems to require that we
simply overturn the best physics on the basis of metaphysical
arguments. Perhaps we could take this line (but it seems a very
challenging route. The arguments for presentism (those stated in
 SS2,
 for instance) look somewhat underpowered when it comes to delivering
that result. The way in which counterarguers have typically tried to
proceed, then, is by giving independent motivations for rejecting the
special theory of relativity (both Crisp 2008 and Monton 2006 may be
read as doing this). An interesting way to pursue this
project is to argue that STR is to be rejected on scientific grounds,
rather than for some purely philosophical reason, suggesting that
another scientific theory (Quantum Mechanics, perhaps) requires
absolute simultaneity. This is the approach taken by Tooley
(1997: 335-71), though in defence of the growing block theory
rather than presentism. Nonetheless, the orthodoxy remains strongly
opposed to this kind of approach.