A (limited) defence of Priorianism

ABSTRACT

This paper defends Priorianism, a theory in the philosophy of time which combines three theses: first, that there is a metaphysical distinction between the present time and non-present times; second, that there are temporary propositions, that is, propositions that change in truth-value simpliciter over time; and third, that there is change over time only if there are temporary propositions. Priorianism is accepted by many Presentists, Growing Block Theorists, and Moving Spotlight Theorists. However, it is difficult to defend the view without appealing to premises that those who reject the view find controversial. My aim in this paper is to defend Priorianism in a way that largely avoids appealing to such premises. I do three things: first (Section 1), I describe the component theses of Priorianism and the relations between them. Next (Section 2), I show how Priorians can respond to the argument that the B-theory implies that there are temporary propositions, and therefore satisfies the Priorian condition for there being change over time. Finally (Section 3), I defend the Priorian thesis that there is change over time only if there are temporary propositions against an alternative principle of change defended by Ross Cameron (The Moving Spotlight, 2015).

KEYWORDS:

• Time
• change
• temporalism
• Arthur Prior
• B-theory

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

1 I don’t claim that all of these works contain explicit defences of the relevant theses, but rather that the views they defend can reasonably be interpreted as views on which the relevant theses are true.

2 Skow (2015, Chapters 11 and 12) describes a number of ‘arguments from experience’ for the conclusion that the present time is metaphysically privileged. See also Spolaore and Torrengo (2019) for the development and rejection of such an argument.

3 This seems to be the case for Prior (1968, 11), for example.

4 Again, see Prior (1968, 9).

5 As an anonymous referee pointed out to me, some philosophers have argued that Priorian views fail to secure ‘dynamic’ change: see e.g. Deng (2013); Fine (2005); Leininger (2015); Lipman (2018); and Skow (2015). Unfortunately, limitations of space mean that it is not possible to consider these arguments here.

6 Read ‘<φ>’ as ‘the proposition that φ’.

7 The claim here is not that every ‘time-specific’ proposition (i.e. every proposition about a particular time) is permanent. For example, Barlassina and Del Prete (2015) argue that <Lance Armstrong won the Tour de France in 2000> has changed in truth-value over the past two decades, and is therefore a temporary proposition.

8 Some philosophers posit a second ‘time-like’ dimension – call it hypertime – and allow that time-specific propositions such as <I am sitting at u> can have different truth-values relative to different hypertimes (even if they have the same truth-value relative to every time). Such propositions would be permanent but also hypertemporary. (Thank you to an anonymous referee for drawing my attention to this point.). Note also that the distinction between temporary and permanent propositions does not map exactly onto the distinction between ‘tensed’ and ‘tenseless’ sentences. For example, whereas the tensed sentence ‘It is raining in New York’ may be taken to express a temporary proposition, the tensed sentence ‘It is now raining in New York’ plausibly expresses a permanent proposition (given the standard tense-logical principle that what is now the case is always now the case). (Thank you to an anonymous referee for drawing my attention to this point.).

9 As well as Prior (1971, Chapter 3), see e.g. Bostock (2004); Frege (1879); Dorr (2016, §4); Jones (2018, 2019); Rayo and Yablo (2001); and Williamson (2003).

10 Or, indeed, as involving implicit first-order quantification over linguistic entities such as predicates or sentences, as on the ‘substitutional’ interpretation of higher-order quantifiers. See e.g. Marcus (1961) for an introduction to substitutional quantification.

11 See e.g. Markosian (2004), Prior (1968), and Rasmussen (2012).

12 See e.g. Forbes (2016) and Forrest (2004).

13 Deasy (2015) defends this sort of ‘traditional’ Moving Spotlight Theory; Cameron (2015) does not. Rather, according to Cameron, this time u is present in virtue of being the unique time t such that for all x, x’s age at t is x’s age simpliciter (where ages are fundamental temporary properties of objects).

14 There are exceptions, however. In particular, although he ultimately rejects the view, Skow’s (2015, §4.3) ‘MST-Time’ combines Temporal Disparity with an apparent rejection of Temporalism. Skow (2015, 67) writes: ‘When I introduced MST-Supertime I discussed the objection that MST-Supertime does not contain objective becoming because in it time does not undergo robust change. The same objection could be made against MST-Time.’ Given that for Skow, a theory T implies that time ‘undergoes robust change’ just in case T implies Temporalism, this seems to be an admission by Skow that MST-Time does not imply Temporalism. Similarly, Deasy (2015) defends a version of the Moving Spotlight Theory that implies Temporal Disparity but does not clearly imply Temporalism (see §4 below).

15 Following Dorr (Counterparts MS).

16 Opponents of Priorianism may respond here by arguing that the fact that there are temporary propositions – conceived by them as propositions that bear the (permanent) true-at relation to some but not all times – does not imply that there is an accurate time. Whether this response is successful turns on the important question of what exactly it is for a proposition to be ‘temporary’. I return to this important question in §3 below.

17 Prior’s use of the expression ‘for some sentence p’ here is, I think, an unfortunate slip, as it gives the unhelpful impression that for Prior, Temporalism is to be interpreted as involving first-order quantification over sentences rather than higher-order quantification into sentence position. However, that would be very surprising given Prior’s clear commitment to irreducibly higher-order quantification: see especially Prior (1971, Chapter 3).

18 See e.g. Zimmerman (2008, 221), who writes: ‘My reason for believing the A-theory is utterly banal[…]: it is simply part of commonsense that the past and future are less real than the present.’

19 For example, according to some B-theorists, for someone to bear the dancing-at relation to a time t is for them to have an ‘instantaneous temporal part’ located at t that is dancing (simpliciter). See e.g. Sider (2001).

20 See also Bostock (2004); Dorr (2016, §4); Frege (1879); Jones (2018, 2019); Rayo and Yablo (2001); and Williamson (2003).

21 See especially Lewis (1983) and Sider (2011). Note that both Lewis and Sider are B-theorists.

22 Note that a commitment to the view that propositions are true/false simpliciter does not preclude holding that some propositions are also true/false relative to times. For example, Priorians who identify times with maximal, consistent, sometimes-true propositions will naturally hold that for any p, p is true-at a time t just in case t implies p. It follows that for any p, p is true simpliciter just in case p is true-at the present (i.e. true) time. The key point here is that for such Priorians, truth-at is analysed in terms of truth simpliciter.

23 See especially Cappelen and Hawthorne (2009) for arguments concerning monadic truth.

24 Or, indeed, on the rejection of ‘standard realism’ á la Fine’s (2005) fragmentalism. See especially Lipman (2015) for a careful discussion of Fine’s view.

25 The question of whether the fundamental property of presentness really is temporary given BST is one that I return to below.

26 BST is not merely a straw-man alternative to Cameron’s view: a very similar view is defended by Deasy (2015). I discuss Deasy’s view in more detail below.

27 According to Cameron (in correspondence), given MAT, this time u time is present in virtue of being the unique time t such that for all x, x’s age at t is x’s age simpliciter. I assume this metaphysically distinguishes u from all other times, so that MAT implies Temporal Disparity. The idea is that given BST, the only role for the tense operators is to capture change in which time is present; therefore, given the above analyses, there are no fundamental tense operators given BST.

28 This is my own reconstruction of Cameron’s argument.

29 Where the truth-predicate is interpreted as expressing a monadic property.

30 See also Cameron (2017).

31 Cameron (in correspondence).

32 Sider (2017, 790, n.2) also recommends this view to MSTers.

33 Although Deasy refers to this as an ‘analysis’ of ‘at t’, it looks more like a way of systematically translating sentences involving ‘at t’ into sentences of the tense operator-free fundamental language of MST. However, not much of importance rests on this point, so I will continue to refer to it as an ‘analysis’.

34 I am grateful to an audience from Trinity College, Dublin and the Society for the Philosophy of Time (SPoT) for comments on an earlier version of this paper. I am especially grateful to Luca Banfi and an anonymous referee for this journal for comments on the MS. This paper is dedicated to my father William P. Deasy (1946–2019). Thanks for everything Bill.