The Ontology of the ‘Now’ in Aristotle
Theodore Scaltsas
University of Edinburgh
Forthcoming in Aristotle on Time, Etudes Aristotéliciennes
Les éditions Ousia, ed. D. Sfendoni-Mentzou
One of the influential, controversial, and eminently challenging areas of Aristotle’s metaphysics is his
theory of time. Its complexity, and the idiosyncratic turns and twists one encounters in it, have not
encouraged commentators to engage with it, by comparison with the attention that the rest of his
metaphysics has received. I will argue in this paper that Aristotle’s account of time is a reciprocally
constructive dialogue with the rest of his metaphysics, which gives him the opportunity to develop
novel metaphysical types of entity. In particular, I will concentrate on the type of entity the now is in
his theory, and try to bring out the ontological makeup of the now, while identifying what about it is
novel for Aristotle’s metaphysics.
Our intuitions about the now
Aristotle begins his investigation about time following his preferred tactic of raising questions
generated from the way we think about time and the now. The first question pertains to the
relation of the now to time itself. Aristotle is wondering what time is composed of, and whether
time is, in view of the fact that on the one hand it is composite, but on the other none of its parts
seem to be. This is because the one part of time extends into the past, and is not any more, and the
other part extends into the future, and is not yet, while the now is not part of time: ‘the now is not a
part, for a part measures [the whole], … but time is not thought to be composed of nows’ (218a6-9).
Already this poses a challenge as to what the ontological relation of the now is to time, especially as
the now, Aristotle continues, appears to be the boundary between past and future.
Aristotle continues with the challenges that the now presents, asking whether ‘the now, … remains
always one and the same or is different from time to time’ (Physics 218a8-10). This raises the
question of the individuation criteria of the now, which seem to point in both directions. On the one
hand, the now is not different from time to time, while on the other it is not the same from time to
time. It is not different because there is no moment at which the now has ceased to be, ‘for we take
it that it is impossible for the nows to be adjoining one another, as it is for a point to be adjoining a
point’ (218a18-10); but if the now does not cease to be in the next moment but at a later one, then
the now will be simultaneous with infinitely many other nows, which is not possible; hence it does
not cease to be. Aristotle’s argument about the second alternative consists of two subarguments, a
straightforward one, and a second with a slight surprise in it. If the now is the same from time to
time, then first, all events will be simultaneous because they will be in the same now.
Second, ‘it is not possible either that the same now should always persist. For nothing that is
divisible and finite has [only] one limit, whether it is continuous in one direction or in more than one.
But the now is a limit, and it is possible to take a finite time’ (218a22-26). In a common sense way
we would agree that if time extends along a line, then a finite segment of it has to have two different
end-limits. But the interesting aspect of the argument is Aristotle’s addition that the same applies to
divisible finite magnitudes which extend in more than one direction. Extending in more than one
direction could mean that the finite line is winding; or it could mean that the magnitude is not a line
but a surface or body. If it is a winding line, the same argument applies again. But if it is, e.g., a
finite surface, does it have more than one limit? Hussey (1983) objects to Aristotle’s point,
introducing the example of a finite circle (p. 140). Hussey does not spell out his argument, but I
believe that it does not present an exception to the claim that Aristotle is making. The reason is that
what Aristotle stipulated is that nothing that is divisible, and finite, has only one limit. This entails
that it has one limit, whereas a line circle has none. If on the other hand we take the circle to be a
surface, then presumably its perimeter is the only limit. Or does the surface have infinitely many
limits at its perimeter? Aristotle says ‘whether it is continuous in one direction or in more than one’.
The representation of time he is proposing is one in which the finite segment begins at the now, and
extends continuously, say in two directions, until the end of the finite segment. Whether the now
begins at the centre of the circle, extending in continuously larger concentric circles all the way to its
perimeter; or the now begins at a point in the surface’s perimeter, extending all the way to another
point of the perimeter (whether crossing the surface or along the perimeter of it), there will always
be the starting and the end points.
These are the challenges that Aristotle poses regarding the nature of the now and of its relation to
time. He immediately raises the question of what time is, and the nature of time, to which we will
turn in order to understand the nature of the now and how it relates to time.
Time and Change
Aristotle examines the received opinions about time, and argues against their adequacy in explaining
what the nature of time is. But his discussion develops into the following conclusion: ‘It is clear that
time is not change and that it is not without change. So it remains, since we are inquiring into what
time is, to start out from this and ask what it is of change’ (219a1–3). His answer, ultimately, is that
‘time is a number of change in respect of the before and after’ (219b1-2), where the primary
application of the before and after is in space, and secondarily in change, and from it in time.
Whether this definition is circular or not, presupposing time to define change, has been the pivot of
the time debate. The majority of the commentators charge Aristotle’s definition with unavoidable
circularity; for example, Owen says:
But can this direction be derived from the spatial before-and-after we have just defined,
without importing just the temporal priority we meant to explain? Evidently not. … if we try
to sharpen the condition by specifying where on the line the movement begins or ends, our
explanation of temporal order becomes immediately circular. (Owen, 1976)
Denis Corish similarly states:
Aristotle’s attempt in book iv.11 of the Physics to derive a temporal order from a similar
order of proteron [before] and husteron [after] movement and spatial magnitude begs the
question by implicitly treating the order of movement as temporal in the first place.1
Julia Annas also maintains a similar criticism; she says,
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.2
Aristotle’s explanation of the priority of the spatial before and after, from which the before and after
in other modalities is derived, is the following:
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 10-19)
Aristotle’s idea is that the spatial relation between objects provides the basis for relativising the
position of each object to the position of the other(s) in some perspectival context that supplies the
priority of the before and after. So from perspective x, object a is spatially before object b; e.g.,
walking towards them one encounters first a and then b. With respect to this change, the encounter
with a is before the encounter with b. So, movement follows the spatial priories in this context.
Corresponding to this movement are the times associated with the movement; so the time of the
encounter of a is before the encounter of b. So, the contextual priority of before and after in spatial
positions translates into a priority in movement and change, in that context, which then also
determines the temporal priorities in that context.
1
2
Corish (1976), 241.
(Annas 1975, n.11).
Would this line of reasoning be sufficient to justify the claim that Aristotle’s definition of time, ‘time
is a number of change in respect of the before and after’ (219b1-2), is not circular? The
straightforward idea would be that the priority underlying the before-after distinction in the
definition of time derives from the priority of the corresponding events of change in motion, and this
latter priority stems from the before and after of the spatial positions of the objects in that context.
The latter might be less obvious than the former, namely, the derivation of the before and after, not
only in movement, but in change in general, from the more fundamental priority of the before and
after in the corresponding spatial locations. Coope (2005: 52) addresses this concern and explains
why Aristotle did not see any problems with this correlation between the priority in change and that
in spatial locations. It is the way Aristotle conceives of change as spreading within an object that
reveals why for him the correlation obtains: ‘The thought seems to be that in a qualitative change a
new property spreads gradually through the changing thing.’ The spread, Coope shows, according to
Aristotle, is in incremental, in steps in which the change unfolds with continuity. For example:
‘When the sea becomes paler, each minimal change (from one shade of blue to the next) spreads
continuously over the surface of the sea. The change in colour is continuous because each of the
spreadings of colour over the surface is continuous. And these are continuous because they each
trace out a continuous spatial path.’ Thus the change, even if it is not movement but qualitative
alteration, follows incrementally the spatial expanse of the object suffering the change, and it is in
this way that Coope justifies Aristotle’s contention that the before and after derives from spatial
relations.
The reason why this is deemed unsatisfactory by the commentators is that it is not clear that the
difference in the spatial magnitude itself can lend meaning to the temporal duration. The priority of
distance of a’s location over b’s, e.g. because a is closer to me than b, cannot convey the priority of
duration in time, i.e. the brevity for reaching a as opposed to the length of time for reaching b. The
reason is that spatial distance does not, by itself, entail anything about temporal duration, or even
about movement. For example, if movement was quantised into ‘jumps’ of unequal length,
difference of distance would be uninformative about difference in duration of change, and hence of
temporal priority.
There have been two interesting attempts in recent work on time at explaining the priority of the
before and after in change and time non-circularly, by Ursula Coope and Tony Roark. Although, as
we shall see, there are difficulties with both these interpretations, I should register that working
through them has improved my understanding of time in Aristotle.
Coope’s attempt to argue for the non-circular account of temporal priority in time and change
begins with her analysis of Aristotle’s definition of change: ‘change is the actuality of that which is
potentially, qua such’ (Physics 201a10–11). Coope says:
‘For our purposes, there are several aspects of this account of change that are important.
First, Aristotle explains change in terms of the notions of potentiality and actuality. His
account makes no explicit reference to time. That there should be such an account of
change is, as I have said, presupposed by his whole project of explaining time in terms of its
relation to change.’
Although Aristotle makes no explicit reference to time in his definition of change, Coope’s
explanation of the definition undoes this. She centres on the ‘qua’ in the definition, namely qua
potential, and explains it in terms of a distinction she takes Aristotle to be drawing between being
bronze, becoming a statue, and being a statue (p. 8). She says:
‘We have already invoked this clause [qua such] in order to distinguish becoming a statue
from being bronze. As we have seen, the change is the actuality of the bronze qua
potentially a statue ... . In order to distinguish becoming a statue from being a statue, we
need to spell out the phrase ‘qua such’ in a way that adds a further emphasis. The change in
question is the actuality of the bronze qua potentially (but not actually) a statue.’ (p. 8)
Coope is not alone in taking the definition of change to mean this. This is the standard way in which
it is taken in the literature, and it is even possible that Aristotle meant it this way. As we saw, she
takes this to be an explanation of change in terms of potentiality and actuality, which leads her to
Aristotle’s notion of the incompleteness of actuality in change: ‘Change is held to be a kind of
actuality, but an incomplete one. The reason is that the potential of which it is the actuality is
incomplete’ (201b31–3). Coope explains this through the actuality of the potential: ‘The bronze's
potential to be a statue is only actual‐qua‐potential when it is not yet a statue’ (p. 9).
Roark objects to Coope’s attempt at a non-temporal account of change because it involves an
ontological commitment to potentialities, and even draws Coope on his side:
“Despite its attractive simplicity, I am convinced that this line of explication is inadequate,
principally because it reifies potentialities. Not only is it implausible to think that Aristotle is
eager to regard potentialities as subjects of predication, it is independently quite difficult to
understand how this might be made to work. As Coope herself laments, ‘This notion of a
potential’s being actual is almost impossible to explain without resorting to metaphor’ (p.
7).”
I disagree on both counts. Far from Aristotle not wanting to regard potentialities as subjects of
predication, he develops a whole theory about potentialities, namely, his account of powers.
Aristotle’s powers are everywhere in his system, doing much of the explanatory work within it, and
he devotes to them one of the central books of his Metaphysics, Book IX. For instance, Aristotle says
there that ‘clearly some potentialities will be non-rational and some will be accompanied by a
reason. This is why all arts, i.e. all productive forms of knowledge, are potentialities; they are
principles of change …’ (Metaphysics 1046b1-4). Aristotle has no difficulty predicating of
potentialities as subjects, and even elevating some potentialities to being the subject matter in the
domains of crafts. Aristotle is not alone in this. Potentialities and powers have become the topic of
study in contemporary philosophy, where philosophers dwell upon the topic of the definition of the
essence of powers.
Furthermore, the difficulty of the actuality of the potential, which both Roark and Coope seem to
find, is not the explanatory dead-end they seem to present it as. Potentialities, or powers, or
dispositions raise a problem because they cannot be known in themselves, but have to be defined in
terms of their effects or manifestation. Additionally, since the actuality of a potentiality qua
potential has not reached the manifestation stage yet, a further question is how this incomplete
actualisation of a potentiality, which is in progress and hence actual qua potential, differs from the
totally unactualised potentiality. Nevertheless, despite these difficulties, a theorist is not at a loss as
to how to proceed epistemologically. Once we have the methodological approach established by
Aristotle – that potentialities are defined in terms of their achievements – then, this can be applied
to either their full or their partial achievements, namely, to either their total potentiality status or to
their incomplete actualisation. This need not be unclear or metaphorical, but straightforwardly
philosophical and in some cases scientific. Contemporary philosophers have recognised this and
don’t shriek away from the actuality of the potential qua potential. Bird (2007) says:
‘Part of the being of a potency is the existence of a potentiality. Since potencies are
essentially dispositional, every potency will have potential manifestations. But these
manifestations may be merely potential. A disposition can have unrealized manifestations.
So the fact that the fragile glass would break if struck is part of the being of the fact that the
glass is fragile, even if the glass is never struck and never breaks.’ (p. 100)
But in contemporary science, too, potentiality enters the domain with such concepts as of potential
energy, which is to be found in physics, chemistry, nuclear physics, and quantum mechanics. More
generally, there is no fear of potentiality, which is posited in both theoretical and applied domains,
in which it carries explanatory weight with no mystery associated with it. The distinction between
complete potentiality and actualised potentiality (which is an incomplete actuality) is not drawn in
contemporary literature along the Aristotelian lines, but the conceptions of the reality of potentiality
or of dispositions that have some unrealised manifestations are close enough to allay fears of
incomprehension in the case of the corresponding Aristotelian conceptions.
But does the actuality of the potential deliver a non-temporal account of change, as Coope and
Roark think? Despite the fact that this is the received conception of the notion of the actuality of
the potential, I cannot see how it can be justified. Let us consider the example that Coope gave, of
the bronze from which the statue was made. The lump of bronze is actually bronze but potentially a
statue. Let us consider the half-point in the construction of the statue, when the sculptor has carved
out the outline, but not the details of the statue. At that point, some of the potentiality of the lump
of bronze to be a statue has been actualised, but not all. In that sense we would be justified in
saying that the potentiality has been actualised, but not fully, because it still has not reached its goal
but remains incomplete, and so still a potentiality for being a statue. So the actualised potentiality
of the bronze to be a statue, while it has still not reached its goal, is the state of the half-built statue.
The question of relevance here is, not how actual the potentiality is, but what it is for it to be actual.
My point is that the actualised potentiality, qua potentiality, is as static a state of the bronze as the
initial potentiality of the bronze to be a statue. This is not what these commentators think.
The actuality of the potentiality marks a difference between the lump of bronze and the half-build
statue. Is this change? More metaphysics is required to show it to be change, both with respect to
the changing subject, and the direction of change. We shall come to the direction of change in what
follows, but let us for now assume that both metaphysical requirements are in place. But even with
these in place, the actuality of potentiality qua potentiality could only mean ‘changed state’. That is,
the bronze is described in two states: one in which it is not at all a statue; and a changed state in
which it is a partially carved out statue. But crucially, what is not given by the actuality of the
potentiality is changing, namely the transition from the one state to the other. And yet, this is what
is assumed by the commentators.
We saw that Coope said that “In order to distinguish becoming a statue from being a statue, we
need to spell out the phrase ‘qua such’ in a way that adds a further emphasis. The change in
question [becoming a statue] is the actuality of the bronze qua potentially … a statue.” (p. 8)
Whence does this follow? It might be thought that it follows from the term that Aristotle uses in the
definition of change for actuality, which is a term he coined himself: entelecheia (Physics 201a10-11),
which we can understand as ‘being in a state of completeness’, and is usually translated as actuality.
But entelecheia will not give us becoming. The entelecheia of potentiality, qua, potentiality is not
the potential becoming actual; it is not a transition from one state to another. Rather, as we have
seen, the actuality of potentiality, qua potentiality, is a static, partially-actualised potentiality. Joe
Sachs (2005) has argued that commentators that translated the actuality of potentiality as the
actualisation of potentiality rather than as the actuality of potentiality, are mis-translating
entelecheia:
“Sir David Ross … writes: “entelecheia must here mean ‘actualization,’ not ‘actuality’; it is the
passage to actuality that is kinesis” [motion, change] (Physics, text with commentary,
London, 1936, p. 359). In another book, his commentary on the Metaphysics, Ross makes it
clear that he regards the meaning entelecheia has in every use Aristotle makes of it
everywhere, but in the definition of motion. as being not only other than, but incompatible
with the meaning “actualization.” In view of that fact, Ross’ decision that “entelecheia must
here [in the definition of change] mean ‘actualization’” is a desperate one, indicating a
despair of understanding Aristotle out of his own mouth. It is not translation or
interpretation, but plastic surgery.” (Sachs, 2005)
Yet, Sir David Ross must be right in thinking that Aristotle means actualisation with the entelecheia
of potentiality qua potentiality. The example Aristotle offers to illustrate the actuality of potentiality
in his definition of change in the Physics makes this clear: ‘the actuality of the buildable qua
buildable is the process of building’ (201b9-10). But, as we have seen, we should not take such
explanations to offer innocent definitions of change in terms of further concepts, in particular, of
actuality and potentiality, but see them for what they are, namely circular explanations explaining
motion in terms of motion – transition, actualisation, becoming.
And yet, as I shall argue, Roark claims to have shown this definition to be a non-temporal account of
change. His approach is different from Coope’s. He holds that Aristotle develops a conception of a
peculiar type of entity, namely one that consists of a combination of a substance and a modal
property, a telic property:
‘[Aristotle’s] definition of motion is couched in terms of substances and telic properties, not
in terms of temporally variant property instantiation. So he is in fact at liberty to define time
in terms of motion without thereby falling into circularity.’ Roark (2011:77)
Roark explains that ‘an example of a telic property is being potentially located in the agora . A telic
property, like a magnetic charge property, endows its possessor with a kind of intrinsic orientation
or directedness within its environment.’ (2011:68) So far so good; his motivation is that the sui
generis metaphysics of Aristotelian properties will carry the weight of the non-temporal explanation
of change. He aims to exploit the directedness of telic properties, namely that telic properties aim
towards a goal beyond themselves. In a way, the directedness of a telic property will be the ‘motor’
of change.
But this account is not any more innocent that the ones we previously examined. There is a
conceptual move that Roark makes which is critical for the innocence of his account. We saw that
he explained a telic property as one which endows its possessor with a directedness within its
environment. But this is a static state of the oriented possessor. Yet this is not how Roark sees it.
He makes a comparison that I believe is metaphysically inappropriate. To explain telic properties, he
compares them to magnetic charge. He begins his explanation of telic properties as follows: ‘A telic
property, like a magnetic charge property, endows its possessor with a kind of intrinsic orientation
or directedness within its environment.’ (p. 68) This is helpful because it serves to explain in an
intuitive way the directedness of a telic property. Magnetic charge is directional, biased like a
corridor or the river bed of a river. But then, Roark derives the result that:
'… the telic property being potentially red. An object that has this telic property is one that
stands in an “attractive” metaphysical relation with the property red, in much the same way
as a magnetized needle stands in an attractive relation with the magnetic poles of the earth,
or as two massive bodies stand with one another in gravitational attraction.’ (p. 70)
This is a significant and crucial metaphysical jump, from magnetic charge to magnetised needle. It is
a jump from ‘potency to act’ which cannot be allowed in the explanation of what ‘actualised
potentiality as such’ means. A magnetised needle is interacting with the magnetic poles, just as two
massive bodies are interacting between them. By contrast, the possession of magnetic charge is not
an interaction with anything; it is not even describing the behaviour of the magnetic object, although
it is providing the tools for explaining its behaviour. The transition from possession of a property to
the exercise of that property in explaining ‘the exercise’ of properties (or powers in potentiality)
begs the question, the same question we encountered above.
Roark thinks he can escape the criticism. He explains as follows:
‘let me pre-empt one line of objection that was all too familiar among critics of
scholasticism, according to which Aristotelian definitions are vacuous. Against such
objections, I must insist: to attribute a telic property to an object is not simply a fancy way of
saying that the object happens to be moving, any more than attributing magnetism to a
needle is simply a fancy way of saying that it happens to align itself with the earth’s
magnetic poles. The attribution of magnetism is intended to explain the needle’s behavior
by revealing something about the structure of reality, and similar considerations apply in the
case of attributing telic properties.’ (69)
This will not do. To attribute a telic property to an object is not at all a fancy way of saying that the
object happens to be moving. Attributing magnetic charge to a needle is describing its state and
structure, which explain its capacities, but it is not describing its action. Roark, with other
commentators, and Aristotle, takes the actualised potentiality as such to be the actualisation of
potentiality; but additionally, objectionably, Roark holds that this offers a non-temporal account of
change. But actualisation is not shown to be non-temporal; on the contrary, it invites temporality in
the very activity of becoming, which it is. Aristotle does not take the further step; time and change
are interdependent in the conception of becoming (the actualisation of potentiality).
A Metaphysical Treasure Chest
It is clear from the discussion above that Aristotle has not offered a way of giving a non-temporal
account of change through the metaphysical analysis of potentiality. In fact, there is little reason to
think that he believed it should be done, since he holds that ‘through the magnitude's [i.e. space’s]
being continuous, the change too is continuous, but through the change, the time. For the amount
of time that has passed is always thought to be as much as the amount of change … through the
following always of the one upon the other of them’ (Physics 219a12-19). I will not engage in the
analysis of his conception of ‘following’, but only to say that the continuity dependence between
them shows that the ‘following’ is not a supervenience relation. Nor is time reducible to change,
and change to space. Although Aristotle is talking about priorities of priorities, namely, priorities in
the arrangement of the before and after in space, in change, and in time, there is no attempt to
reduce the one to the other. Priorities for Aristotle may arise from a host of different metaphysical,
or epistemological perspectives, independently of reducing one phenomenon to others. What is
clear is that Aristotle establishes the interdependence of time, change, and space relations.
But what is exceptional about his exploration of time through the interdependence with change and
space is the astonishing, and unique wealth of ontological innovation that Aristotle displays here,
populating his metaphysics with new types of entity in order to address the ontological
requirements of time. In what follows will examine the types of entity that play a role in Aristotle’s
account of time, in an effort to come to understand the metaphysics of this elusive entity, the now.
But this is only one aspect of what there is to discover in these passages. I believe that equally
importantly, his discussion of time reveals significant features of Aristotle’s methodology in
developing his metaphysics. Aristotle is classified as a card-carrying substance-ontologist, so much
so that e.g. Roark (2011:3) builds his whole interpretation of time in Aristotle on an attempt to base
the ontology of Aristotle’s account of time on his account of substances.
But the analysis of the ontology of the now is complex. In consequence, I will first offer in the
present section a metaphysical description of the types of entity we encounter in Aristotle’s analysis
of time, anticipating his analysis. Then, in the following section, I will come to his account of the
now, where we shall encounter these types of entity. The hope is that in this way we shall be
prepared for comprehending the exceedingly complex passages on the now.
Aristotle’s account of substance is familiar. Substances are hylomorphic compounds of substantial
form and matter. The par excellence cases of substances are planetary bodies or biological
organisms, which are perpetual in nature. Each substance is a subject of properties, some of which
are essential (or derivatively, necessary), and some accidental. In change, the substantial subject
gains or loses properties. In substantial change, that is, in generation or corruption, the hylomorphic
compound dissolves, and the matter that survives acquires a new form (either a substantial form, or
a non-substantial form, e.g. of dead-wood). What is important for the present discussion is that the
substantial subject is the carrier of oneness and continuity in substances, enduring accidental
changes through time.
Related to the substantial subject is another type of entity that some times emerges in Aristotle’s
discussions, namely, accidental unities. An example of this is ‘musical man’, considered to be an
entity of its own (individuated by abstraction from a person that is musical). Accidental unities are
not separate entities, but dependent on substances, or more broadly, objects. They are in some
sense comparable to phases of substances; both are ways of articulating substances, by abstraction,
in order to best understand their structure, and features. The explanatory work that accidental
unities do in Aristotle’s system is limited. Their role is confined to ontological discussions, and they
do not figure in Aristotle’s semantics. Accidental unities are ways of creating oneness and continuity
on the ground of accidental properties of objects – e.g. while the person is musical, and in so far as
he is being musical. ‘Being musical’ is essential to the abstract entity ‘musical man’; but it is
accidental to ‘man’.
If a change is a transformation, rather than merely accidental to a substance, and a substantial form
is lost or gained, it is the substratum that becomes the carrier of oneness and continuity through the
change. We do not normally have need for individuating substrata; such a case would be, e.g., to
refer to materials that are extracted from other compounds, e.g. in extracting fat from cheese.
Aristotle individuated substrata to explain the difference between change and transformation. The
survival of material substrata through transformation (like substantial subjects through change)
were the Aristotelian answer to Parmenidean concerns about generation ex nihilo.
But substrata turned out to be very useful to Aristotle in his metaphysics, not just for answering
Parmenides. A prime example is that of a point, one that connects the two halves of a line, but also
divides them. As a dividing point, it is the end of one half of the line, and the beginning of the other
half of the line. In that sense, Aristotle observes, it is two points, although a single dot. What
grounds the claim for two different points is the fact that the dot is associated with two different
functions. The one is to be the end, and the other the beginning of two different lines. In fact, as
such, the one point belongs to the one half-line, and the other to the other half-line. Yet, as a
connector, it is only one point. It has only one function, namely to connect the two parts of a line.
So, is there one, or are there two points in the line? Aristotle says, both: ‘For the intellect, it is not
always one and the same point, since it is other and other when one divides the line; but in so far as
it is one, it is the same in every respect’ (Physics 222a16-17). It is important that Aristotle says ‘for
the intellect’, a rare occasion of making such a qualification. It shows something important about his
methodology – that in trying to achieve comprehension, the ontology will follow explanation
through the powers of abstraction. A single point, although indivisible qua point, is divided (from
itself) by virtue of its functionality. We can follow this, when we recognise what the existential claim
means; once we realise what the individuation criteria are for these entities, we recognise how they
are interrelated. At heart, there is the substratum – the dot – which may be associated with one
function, or with two functions. In so far as we can understand what it is for the same dot to be
performing two different functions, which it can, then we are given the perspectives from which the
dot constitutes two points. In so far as the dot is associated with only one function, the dot
constitute one point. We find a way to come to terms with the ontology because we accept the
explanation.
In the example of the point, the overall oneness and continuity is carried by the substratum, the dot,
which underlies all points, single or divided. But further instances of oneness and continuity are
carried by the points that are constituted of the dot and its various functions. This makes such a
type of entity – or type of ontological complexity – a very useful metaphysical tool for Aristotle.
Finally, there is a fascinating type of entity that surfaces in Aristotle’s discussion here, which I have
not encountered elsewhere in Aristotle’s works. The conception for this type of entity is framed just
before Aristotle comes to discussing time, while he is examining infinity. He says:
‘But the phrase 'potential existence' is ambiguous. When we speak of the potential existence
of a statue we mean that there will be an actual statue. It is not so with the infinite. There
will not be an actual infinite. Being is spoken of in many ways, and we say that the infinite is
in the sense in which we say it is day or it is the games, because one thing after another is
always coming into existence. For of these things too the distinction between potential and
actual existence holds. We say that there are Olympic games, both in the sense that they
may occur and that they are actually occurring. For generally the infinite has this mode of
existence: one thing is always being taken after another, and each thing that is taken is
always finite, but always different. Again, 'being' has more than one sense, so that we must
not regard the infinite as a 'this', such as a man or a horse, but must suppose it to exist in the
sense in which we speak of the day or the games as existing – things whose being has not
come to them like that of a substance, but consists in a process of coming to be or passing
away; finite, yet always different’ (206a21-29).
What type of entity, then, is a day? How does it resemble the infinite? Aristotle says that the
infinite cannot be actual, but is like we say it is day. But for day, as for games, we can say that they
are actual, in the sense that they are actually occurring. To resolve this, we need to introduce a
further distinction that will allow the infinite, and day in so far as it resembles the infinite, to be both
actual and not actual. It must be that, in thinking that the infinite is not actual, Aristotle means that
the infinite will never be completed. And yet, we can refer to it. To what is it that we refer to when
we refer to the infinite. It cannot be like referring to the number 5, which is a whole. What Aristotle
needs is a way of referring to the infinite as it is being ‘produced’, rather than as a whole after
production (which it never reaches). Now, ‘day’ can refer to a whole day, e.g. the fourth day of last
week; in so far as it does this, it would not serve to explain the sense in which the infinite is actual,
since it is a whole day. But in so far as we can talk of ‘being daytime’ now, it can serve to explain the
production of the infinite. The criterion that is operational must be that the individuating forms of
the infinite, or of daytime, or game-time do not extend into the past or the future but only the
present. This is in sharp contrast to the individuating form of a substance, which, as Aristotle says, is
a ‘this’: When Alexander says Bucephalus is powerful, ‘Bucephalus’ refers of the whole substance, as
one, from Bucephalus’ birth, to its death. The form of ‘being a horse’ extends diachronically to the
whole existence of the horse, including the unrealised phases, which comprise Bucephalus. But not
so with the infinite, in Aristotle’s conception, or with daytime. When I say ‘it is daytime’, I am not
saying anything about what it was two hours ago or what it will be two hours hence. I am not
referring to “today”, but to the present state of affairs of daylight, as it is developing and unfolding.
The individuation criteria of ‘being daytime’ do not extend beyond the present. Similarly, the
individuation criteria of ‘infinite’ do not extend beyond the present, e.g. the process of division or
addition.
It should not be thought that this is the way that Aristotle individuates processes. He has no
difficulty accounting for talk of house-building as a process that begins with the builder’s conception
of the house and ends with the completion of the house; e.g. the house-building required four
months. Rather, his introduction of the example of daytime is a brilliant way of allowing for the
individuation of an incompletable actual process.
I have gone through this itemisation of Aristotelian types of entity, because Aristotle uses these
types in the explanation of his ontology of the now. We shall now turn to his account of the now.
The ontology of the now
The core challenge Aristotle fames in his account of the now is the following: “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? It is hard to say.” (218a8-11) He formulates the dilemma on the basis of received
opinions about the now and takes as his starting point that the now is not part of time: “a part is a
measure of the whole, which must be made up of parts. Time, on the other hand, is not held to be
made up of ‘nows’” (218a6-7) … “the 'now' is no part of time nor the section any part of the
movement, any more than the points are parts of the line” (220a19-20). So the now is
instantaneous, and has no duration.
Aristotle then addresses the fundamental challenge: “The 'now' in one sense is the same, in another
it is not the same.” (219b12-13). This is a metaphysical challenge, for which he will invent
ontological ammunition to resolve it. We shall turn to this, to evaluate his arguments and discern his
position.
Aristotle offers a truncated, complex, as well as surprising explanation of the sense in which the now
is the same and different. To understand what he is trying to explain with his account we need to
engage in a thought experiment in which time is represented as a point traversing a line; we further
need to raise, ourselves, the question: what is it that is different between a point traversing a line,
and the now traversing time? The now can certainly be thought of as a point that traverses time.
But it is a special point, and the question is: what metaphysical account will show what is special
about this point?
Aristotle sets up a comparison between a point, which represents the now, and a body that is being
carried. The now is travelling as a point along a line, representing the current flow of the movement
of the body that is carried. Aristotle explains that: “This, whatever it is, is the same (whether a point,
or a stone, or something else of the kind), but it has different attributes, as the sophists assume that
Coriscus' being in the Lyceum is a different thing from Coriscus' being in the market-place.” (219b1821). What is important to observe here is that Aristotle is not talking about a substratum – despite
translations of the same passage to this effect, e.g. in Barnes (1984) ‘This is an identical substratum
(whether …)’. There are three indicators that should dissuade us from thinking that Aristotle is
talking about a substratum. First, his expression in question is non hupokeimenon but ho men pote
on (whatever it is); secondly, he gives as examples the point (stigma, not sēmaion, dot), or a stone,
etc., which are not substrata for him, but hylomorphic compounds – although not necessarily
physical (as Aristotle believes there is noumenal matter of abstraction, as well); thirdly, Aristotle
proceeds to give an example for the identity of the now, using a person, Coriscus, not his material
substratum. Indeed, my contention is that the reason why Aristotle uses such generic expression as
‘this, whatever it may be’ in order to refer to a metaphysical aspect of the now indicates that he is
not referring to any of the stock ontological components of entities in his metaphysics, but
innovating. This is confirmed by the example of Coriscus.
Aristotle then explains the sameness of the now with an example from the Sophists. We saw that he
says: ‘This, whatever it is, is the same (…) but is different in account [logōi] as the sophists assume
that Coriscus' being in the Lyceum is a different thing from Coriscus' being in the market-place’
(219b20-21). Here Aristotle borrows an example from the Sophists precisely because his own
metaphysics would not allow him to say that Coriscus is a different thing in the Lyceum and in the
market-place, since he is the same substance. Aristotle’s metaphysics would have a way of
explaining the difference between Coriscus-in-the-Lyceum and Coriscus-in-the-market-place as two
different accidental unities, which surface rarely in his system (but he does not choose to introduce
his example in this way here). Why does Aristotle need this example?
The answer is not straightforward because there is nothing in the now which corresponds
metaphysically to Coriscus in Coriscus-in-the-Lyceum. Let us proceed in small steps. Aristotle wants
to show that there is something common between the nows every (different) time we register a
now, but also that they are different, because the times are different. Are the nows more similar or
more different? How metaphysically primary is the common element between the nows in each of
them, and how primary is what is different in each of them? Aristotle’s example of Coriscus does
not help us answer this question, precisely because there is nothing in a now that corresponds to
Coriscus. But it alerts us to the primacy of the sameness between the nows, indicating by the choice
of the example that the ‘presentness’ of a now cannot be represented by the a substratum, but
rather by a subject.
To understand the metaphysical structure of a now, and hence what is common and different
between nows, we need to consider the following about it. A now, like a point in a line, is the limit
of two converging half-lines – the end of one, and beginning of the other – ‘the point both connects
and terminates the length-it is the beginning of one and the end of another.’ (220a10-11). But the
now is always present, namely, the now travels in time. Hence it needs to be corresponded, not to a
fixed point on a line, but to a point that is traversing a line. The form that defines what such a point
is would be that of being a limit of converging half-lines, only that the limits involved at each
moment (and the corresponding half-lines) are constantly changing. This is what the Coriscus
example is trying to capture with the always changing unity of Coriscus-at-a-place, but it does it with
small success, because of the disproportionate metaphysical significance of the substance, Coriscus,
in that accidental unity, which Aristotle’s metaphysics has made plain to us. Nows are not
structured like Coriscus-at-a-place.
I wish to argue that Aristotle does answer this question about the metaphysics of the travelling now,
but not in the immediate context. The metaphysical model that we need in order to understand the
make up of a travelling point on a line, or of the flowing now, is given to us in Aristotle’s introduction
of the type of entity that day, and games are. We saw that he contrasts them to substances, and
explains what they are as entities that remain the same while their constituents are continuously
changing. (Substances are always in activity, but they differ from such entities as day or games in
that they are diachronic, and their constituents need not be constantly changing.) Furthermore,
what the day or games individuate are not objects, but, in these cases at least, states of affairs – of
daylight, or of games occurring. This fits moving points prardeigmatically, since their constituting
limits are continuously changing.
Let us then conclude with the metaphysical structure of the now. The now is not a part of time,
because it has no duration; but “the 'now' and the 'before' and the like are in time” (221a14-15), as
points are in lines. The now has no duration because it is the limit of the converging before and
after in time. As such it always has the structure of a limit of two converging lines; but since time
flows, the lines of the before and after continuously change and with them the limit on which they
converge. Thus the now at different times is the same, in the sense in which the colour of the wall
under the same conditions of daytime is pale blue. The now of different times is different, because
the constituents of the now, say, at 12:00 p.m. and at 2:00 p.m. are different. The metaphysics of
such entities as the now and daytime is fundamentally different from the metaphysics of substances,
because they are not individuated diachronically, as substances are. Their existence captures
persisting states of their changing constituents.
Aristotle does not give us a full individuation account of the type of entity the now is. But the
metaphysics of the now has led him to new territories of ontology, which enrich his metaphysical
system with types of being we do not encounter elsewhere in his works. His investigation also
displays the methodological readiness with which he is willing to modify and expand his ontology.
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