On the Role of Presentism in Aristotle’s Account of Time



Aristotle’s Presentist Account of Time and the Charge of Circularity

by Kenneth Boyce

Last Revised 4/11/12

Abstract: Various commentators have charged Aristotle’s discussion of time in Physics IV 10-14 with being illicitly circular. In this paper, I defend Aristotle’s account from such charges. I do so by arguing that those who make them fail to properly understand Aristotle’s aims. In particular, I argue that Aristotle is attempting to dissolve certain puzzles that arise for him because he holds a presentist view of time. I further argue that once Aristotle’s aims are properly understood, the charge that his account of time is illicitly circular is seen to be misplaced.

Introduction

Various commentators have charged Aristotle’s discussion of time in Physics IV 10-14 with being illicitly circular. Taking Aristotle to be attempting to show that all temporal facts can be reduced to non-temporal ones, they charge that he illicitly appeals to notions that presuppose prior reference to time (such as motion and temporal direction). In this paper, I defend Aristotle’s account from such charges. I do so by arguing that those who make them fail to properly understand Aristotle’s aims. In particular, I argue that Aristotle is attempting to dissolve certain puzzles that arise for him because he holds a presentist view of time. I further argue that once Aristotle’s aims are properly understood, the charge that his account of time is illicitly circular is seen to be misplaced.

I. The Charge of Circularity

In Physics IV 11, Aristotle defines time as “number of motion in respect of ‘before’ and ‘after’” (219b 1).[1] Aristotle also maintains that by coming to realize that time is the number of motion, we can account for various features that time has, such as its having a linear order and being continuous. We can account for these features, he suggests, by noting that they correspond to features had by a spatial interval, over which motion occurs.

In his own words,

But what is moved is moved from something to something, and all magnitude is continuous. Therefore the movement goes with the magnitude. Because the magnitude is continuous, the movement too is continuous, and if the movement, then the time; for the time that has passed is always thought to be as great as the movement. The distinction of before and after holds primarily, then, in place; and there in virtue of relative position. Since then before and after hold in magnitude, they must hold also in movement, these corresponding to those. But also in time the distinction of before and after must hold; for time and movement always correspond with each other. (219a 10-20)

Here many commentators have taken Aristotle as attempting to offer an account of time according to which all of the features of time can be shown to derive from features of movement (and ultimately from the features of spatial magnitude, insofar as movement inherits those features in virtue of occurring over a spatial magnitude). Many of these commentators have also charged that, in making this attempt, Aristotle illicitly appeals to temporal notions.[2],[3]

G.E.L Owen states, for example,

[Aristotle] wants to show that spatial order is conceptually basic to the rest, that by starting from this we can explain the order of movement, and at another step the order of time, without circularity – i.e. without importing into our explanations the things they were meant to explain. The enterprise fails.[4]

Denis Corish similarly states,

Aristotle’s attempt in book iv. 11 of the Physics to derive a temporal order of [before] and [after] from a similar order of movement and spatial magnitude begs the question by implicitly treating the order of movement as temporal in the first place.[5]

Julia Annas also maintains something similar. She states,

It would in fact be an error to make time logically derivative from motion, because motion or change already involves time. Aristotle recognizes this at 222b 30–223a 15: all motion is (relatively) fast or slow, and this involves the notion of covering a distance in more or less time. But he does not remain sufficiently aware of this, or he would have suspected a covert circularity in the scheme in which before and after in time is derived from before and after in motion and this in turn from a primary before and after in space.[6]

Some of the above charges of circularity, it would seem, have more to be said for them than others. The charge that Aristotle’s account is circular because it appeals to motion and motion involves time, for example, is, perhaps, easily dispatched with. As other commentators on Aristotle have pointed out, Aristotle elsewhere provides an account of motion and change that makes no appeal to temporal notions.[7] And, as other commentators have suggested, perhaps various features of Aristotle’s account of motion can be exploited to absolve him from the charge that his attempt to derive the direction of time from motion and spatial magnitude is circular.[8]

Regardless of what else might be said in Aristotle’s defense against the charge that his account of time is circular, however, I believe that this charge can be seen to be misplaced for another reason. What all of the above charges of illicit circularity share in common is the presupposition that Aristotle aims to provide a reductive account of time, one according to which all the temporal features of the world derive from antecedently non-temporal features. It is this presupposition that I will challenge in the following sections.

II. Aristotle’s Puzzles About Time

The best way to understand Aristotle’s aims when giving his account of time is to start where Aristotle himself does – with the opening discussion in Physics IV 10 concerning various puzzles surrounding the nature of time. Commentators offer different enumerations of these puzzles;[9] for my purposes, it suffices to see Aristotle as offering two.

The first puzzle may be found in lines 218a 1-10. Here Aristotle informs us that it seems problematic to think that time exists given that “if a divisible thing is to exist, it is necessary that, when it exists, all or some of its parts must exist.” But it would seem, Aristotle explains, that none of the parts of time exist. For, on the one hand, the past and future do not exist. And while the present instant (“the ‘now’,” as Aristotle calls it), we might say, does exist, it is too small to be considered a part of time, since (Aristotle holds) no extended thing can be made up of a collection of entities that have no extension.[10]

The second puzzle is found on lines 218a 11-29. Here Aristotle poses the following question: “The 'now' which seems to bound the past and the future – does it always remain one and the same or is it always other and other?” Aristotle notes that it seems that we cannot give a satisfactory answer to this question. If we say that the now is always different, then Aristotle points out that we seem to be committed to the claim that a prior now has ceased to be. But, Aristotle notes, we cannot say that the now “ceased to be in itself (since it then existed).” So it seems that we have to say that it ceased to be in another now. But if we answer that way, Aristotle argues, we find ourselves mired in paradox. For, Aristotle insists, time is continuous, and for that reason it cannot be the case that any now is next to another. And so, Aristotle concludes, had the prior now ceased to be in another now, it would have, in the interim, existed “simultaneously with the innumerable 'nows' between the two – which is impossible.”

On the other hand, Aristotle points out, it seems that we cannot say that the now is always the same, since then our answer runs afoul of the fact that none of the (non-overlapping) parts of time are simultaneous with another (so that “things which happened ten thousand years ago would be simultaneous with what has happened to-day, and nothing would be before or after anything else”). Furthermore, it also seems that we can’t say that the now is always the same, Aristotle notes, since “the 'now' is a termination” (i.e. a point of potential division within time), but time is “continuously extended” and “no determinate divisible thing has a single termination.”[11]

What both of these puzzles share in common is that they appear to reveal an inconsistency between two theses concerning the nature of time. The first of these is that our ordinary ways of thinking and talking about time commit us to the existence of an extended, continuous, linearly ordered temporal dimension (analogous to a spatial dimension) that contains past and future times as proper parts – call this “the extended thesis”. The second of these is the thesis that there are no merely past or future entities, that everything that exists, exists presently. Call this “the presentist thesis”.

We see these two theses being contrasted in a rather straight forward manner in the first puzzle. There time is envisioned as something continuously extended and as having past and future times as parts (the extended thesis). Yet (as the puzzle has it) none of the extended parts of time exist because only the present instant does (the presentist thesis). The second puzzle also relies on both of these theses to generate a paradox. It relies on the extended thesis insofar as it relies on the premise that time is composed of continuously divisible parts, none of which are simultaneous with each other. It relies on the presentist thesis insofar as it relies on the premise that if the now is always different, then the prior now must have ceased to be (note that someone who did not hold to the presentist thesis could simply maintain that the prior now exists as a wholly past entity and thus never ceased to be).[12]

Of course, as matters stand, all we have here is an indication that Aristotle takes the extended thesis and the presentist thesis to be in apparent conflict with one another. We do not as yet have any indication as to whether Aristotle takes the above conflict to be genuine, nor do we have any indication that Aristotle himself adopts either of the above two theses. As I will argue below, however, Aristotle is best read as attempting to show how we can resolve the apparent conflict by rejecting one of the above theses in favor of the other. In particular, I will argue that the textual evidence indicates that Aristotle rejects the extended thesis in favor of the presentist thesis. I will begin my exegetical case by starting with an observation made by Julia Annas.

III. Aristotle’s Presentism

In her article “Aristotle, Number and Time,”[13] Julia Annas argues persuasively that, in defining time as a kind of number, Aristotle intends to assimilate his account of the nature of time to his anti-Platonist account of number given in Metaphysics X 1-3. As Annas points out, in Metaphysics X 1-3, Aristotle develops an account of number that is thoroughly anti-Platonist in character, an account intended to show that “statements apparently about numbers do not in fact require reference to be made to any such entities as [abstract] numbers (p. 99).” Rather, as Annas points out, according to the account of number that Aristotle gives in Metaphysics X, the sense of mathematical statements that, on the surface might seem to refer to abstract numbers, “is fully given by statements in which no such apparent reference occurs, which only involve counting and measuring” (p. 99).

Annas further notes that in Physics IV 10-14, Aristotle, in defining time as a kind of number, appears to be similarly concerned with giving (what Annas refers to as) an “anti-Platonist account of time” (p. 100). Annas notes, for example, in Greek as well as English, “ordinary talk about time tempts us naturally enough to [a] Platonist view [of time],” in which time is held to have an existence that is independent of concrete things, “or at least into vague acceptance of Time as a mysterious cosmic entity or container” (p. 102). “In Greek particularly,” Annas points out, “there are many idioms with this kind of implication.” “Time is what ‘includes’ or ‘enfolds’ everything, and is thought of as a boundless resource that will never give out; there is a time greater than any time” (p. 102). Annas further notes that “Aristotle takes these idioms very seriously, and thinks it important to give a non-Platonist interpretation of them” (p. 102). Thus, according to Annas, in giving his account of time, Aristotle “applies his general definition of time as a kind of number at specific points …” in an attempt to show that such “idioms should be analyzed like the corresponding number idioms”, the latter of which involve no reference to entities over and above those which we count and measure (pp. 105-107; here Annas refers in particular to 221a 9-30, 221b 14-6, 224a 2-15).

Note that what Annas describes as a “Platonist account of time” is very similar to what I have been referring to as “the extended thesis”. The Platonist thesis, as Annas describes it, is a thesis according to which time is some sort of “mysterious cosmic entity or container” that “‘includes’ or ‘enfolds’ everything.” Likewise, according to the extended thesis, time is constituted by an extended, continuous, linearly ordered temporal dimension that contains past and future times as proper parts. Aristotle, on Annas’s reading, is assimilating his account of time to his account of number in order to avoid such dubious ontological commitments, while retaining the truth of our ordinary talk and beliefs about time.

At this point, however, an interpretive puzzle arises. As Annas herself notes,

“there seems to be little to prevent the extension of Aristotle’s treatment of time as a number to magnitude or length,” but Aristotle never does this. As Annas notes, Aristotle “certainly seems to find the existence of time more problematic than that of magnitude (as opposed to unmeasured space), but it is hard to see why.” “This,” she points out, “raises the interesting question of why Aristotle makes his sole application of the [Metaphysics X] ideas to time, and not to the other continua” (p. 109).

The hypothesis that in giving his account of time Aristotle is rejecting the extended thesis in favor of the presentist thesis provides us with an answer to these questions. Aristotle offers puzzles that seem to show that the presentist thesis is incompatible with the extended thesis; and given that (ex hypothesi) Aristotle retains his commitment to presentism, the existence of an extended temporal dimension becomes problematic for Aristotle in a way that spatial extension does not.

Furthermore, this interpretation fits well with Annas’s observations concerning Aristotle’s assimilation of his account of time to his account of number. Just as in Metaphysics X Aristotle is concerned to show that our activities of counting and measuring things do not involve us in any ontological commitments over and above the things we count and measure, so he is concerned in his discussion of time to show that our activities of timing don’t involve us in any additional ontological commitments. His insistence that various features of time correspond to features of motion and spatial extension can be understood as part of an attempt to show that we acquire no ontological burden in our talk about time that we do not already acquire in our talk about motion and spatial extension. In so doing, Aristotle attempts to give us an account of our talk of time that does not commit us to past and future times, one that is compatible with a thoroughgoing presentism.

IV. Dissolving the Circularity Charge

If the interpretation of Aristotle that I have been presenting is correct, we can also see that charges of circularity against his account are misplaced. As my interpretation would have it, Aristotle is not so much concerned with reducing all of the temporal features of the world to non-temporal features, but with showing that our ordinary beliefs about time do not involve us in any ontological commitments that are incompatible with presentism.

But if this is what Aristotle is concerned with, he is free to invoke whatever concepts he has available to him – including temporal concepts (e.g. temporal direction) – to further his aims.[14] Indeed, as contemporary discussion has borne out, presentists already have independent motivation to take facts about tense as irreducible.[15] And so Aristotle’s invoking temporal notions like before and after to absolve us of unwelcome ontological commitments fits well with an overall presentist outlook.

What about “the ‘now’,” which figures so prominently in the puzzles that Aristotle raises? A fully adequate discussion of Aristotle’s view of the now is beyond the scope of this paper. Nevertheless, if my interpretation is correct, one would expect that he attempts to dissolve puzzles that arise from our talk of the now by showing how that talk relates to the counting and measuring of presently existing things. And this is just what we find. In 219b 10-30, he purports to explain how it is that the now is in one sense always the same and in another sense always different by appealing to how a moving body (the motion of which time is the measure) is in one sense always the same and in another sense always different. A moving body, he reminds us, is the same in “substratum”, but different in “definition,” “as the sophists assume that Coriscus’ being in Lyceum is a different thing from Coriscus’ being in the market-place.” So too, Aristotle contends, “the ‘now’ corresponds,” in this respect, “to the body that is carried along.”

Of course, I have not shown that Aristotle succeeds in showing that our beliefs about time do not involve us in any further ontological commitments than do our beliefs about spatial extension and motion. Nor have I explained just how Aristotle purports to show this. Nevertheless, I believe that I have made a good prima facie case that while Aristotle’s aims in giving his account of time are ontologically deflationary, his account of time needn’t be reductive in order for him to achieve those aims. And provided that his account needn’t be reductive, the charge that it is illicitly circular on account of its relying on temporal notions is misplaced.[16]

Works Cited

Annas, Julia (1975) “Aristotle, Number and Time” The Philosophical Quarterly, 25, pp.

97-113.

Barnes, Jonathan (1984) The Complete Works of Aristotle, 2 vols. (Princeton University

Press).

Broad, C.D. (2001) “Ostensible Temporality” Metaphysics: Contemporary Readings

edited by Michael J. Loux (Routledge), pp. 272-278. Excerpted from Examination of McTaggart’s Philosophy by C.D. Broad (Cambridge University Press, 1938), pp. 309-313.

Coope, Ursula (2005) Time for Aristotle (Oxford University Press).

Corish, Denis (1976) “Aristotle’s Attempted Derivation of Temporal Order from That of

Movement and Space” Phronesis, 21, pp. 241-251.

Kretzmann, Norman (1976) “Aristotle on the Instant of Change” The Aristotelian

Society. Supplementary Volume 50.

Owen, G.E.L. (1976) “Aristotle on Time” Articles on Aristotle, vol. 3, edited by Jonathan

Barnes, Malcolm Schofield and Richard Sorabji (New York: Saint Martin’s Press). Originally published in Motion and Time, Space and Matter: Interrelations in the History and Philosophy of Science. Edited by Peter Machamer and Robert Turnbull (Ohio State University Press, 1976).

Roark, Tony (2003) “Aristotle’s Definition of Time is Not Circular” Ancient

Philosophy, 23, pp. 301-319.

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[1] All quotations of Aristotle are from (Barnes 1984).

[2] For a more thorough discussion of this charge and the various forms that it takes, see (Roark 2003). My own discussion of the charge in this section is heavily indebted to Roark’s.

[3] Actually, there are at least two distinct charges here that can and have been made against Aristotle’s view. Aristotle’s account might be charged with being conceptually circular insofar as it invokes temporal concepts in attempt to analyze those very concepts. Or Aristotle’s account might be charged with being ontologically circular insofar as it attempts to show that temporal features of the world ontologically reduce to non-temporal features of the world but winds up including temporal features of the world in its reduction base. (On this very distinction, see (Owen 1979, 157) and (Roark 2003, n.7)). Since the response to the circularity charge that I will offer can be made against either of the above versions, however, I will not take great pains to distinguish the two (rather; I will shamelessly conflate them); nor will I attempt to tease out which version of the charge is being offered by each of the authors I cite (although, see the note below).

[4] (Owen 1979, p. 157). Note that, in Owen’s case, it is clearly the conceptual version of the circularity charge that is in view (see the above note). In fact, immediately above the quote cited here, Owen explicitly states in his article that he does not believe that Aristotle intends to show that time is ontologically reducible.

[5] (Corish 1976, p. 241). NB: I inserted English translations of Greek terms where brackets appear.

[6] (Annas 1975, n.11).

[7] See, for example, (Coope 2005, 5-9) and (Roark 2003, 306-310).

[8] Roark (2003) has noted, for example, that Aristotle’s account of change is fundamentally teleological so that, on Aristotle’s view, every change has an inherent teleological direction. Roark further suggests that this fact about Aristotle’s account of change can be exploited in such a way as to account for how there could be a non-circular derivation of the direction of time from the direction of change. For a different yet similar suggestion, see (Coope 2005, 72-75).

[9] Kretzmann (1976), for example, is representative of a number of commentators in seeing four puzzles here.

[10] For Aristotle’s argument for this conclusion, see Physics VI 1.

[11] For helpful discussions of this point, see (Kretzmann 1976, 97) and (Coope 2005, 9-13).

[12] Strictly speaking, all that is required to generate the particular puzzle that Aristotle raises is the claim that prior nows have ceased to be. So, strictly speaking, it is not presentism, per se, that is required to generate that puzzle, but merely the claim that past times do not exist. However, it is easy to generate a parallel puzzle given the claim that future times, but not past ones, exist (as certain views of time, such as shrinking tree theories, would have it): If future times, but not times past, exist, and the now is always different, then the current now will cease to be. But we can’t say that it will cease to be in itself …

[13] (Annas 1975).

[14] I thank Michael Loux for this point. Coope (2005) also considers the possibility that Aristotle is simply not offering a reductive account of temporal asymmetry as a way of defending Aristotle from the charge of circularity (see p. 71), but she then proceeds to develop an alternative suggestion.

[15] Presentists are A theorists. And, as indicated by Broad (2001), a natural way for an A theorist to evade McTaggart’s paradox is by taking tense as primitive.

[16] I thank Anne Peterson and Michael Loux for helpful comments.

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