The previous article article on the flow of time discussed the dynamic and static theories of time that have occupied philosophers throughout history pointing out the way we seem to mark time in two distinct ways, either with the changing properties of past, present, and future, or with the fixed relationship of before and after. Past, present and future are established in relation to an ever-changing point in time that we call ‘now’ or the present. The relationship ‘before’ and ‘after’ does not refer to or need the idea of ‘now’, it is simply a ‘timeless’ relationship between events … it does not demand that things ‘flow’, ‘move’, or ‘lapse’. This second static view of time is the one preferred by science which finds no need for temporal flow. And yet change in the universe seems undeniable, a primitive, brute fact.
How can we possibly claim that change is a subjective phenomenon, just something we feel, rather than something that is actually going on outside our minds? Various philosophers have claimed that not only is change in the universe real, time does not exist as an object in the universe separate from other things, time is simply change itself. Notable among these philosophers was Plato’s student Aristotle who regarded time as a unit system used to count, order, or measure things. The tradition has continued to the present day with, for example, the Australian philosopher Jack Smart describing time as the ‘dimension of change‘. If we are struggling to define time in terms of change then the denial of change itself is very useful – because it means that the reality of time can be quickly denied too.
So what have we learned about change in the course of history?
Permanence & change
The philosophical conundrum of permanence and change in the universe dates back to at least the Eleatic pre-Socratic philosophers and was expressed by Plato through his ideas of Being and Becoming (see Socrates, Plato, Aristotle). It is easy to dismiss this dichotomy of thought as fanciful and unproductive philosophical speculation but it is still with us today in modern science with science taking the more ‘other-worldly’ view. The pre-Socratic philosophers Parmenides and Zeno argued that change was a kind of idea in the mind – they were what we earlier called idealists. To make the point about the subjectivity of change Zeno (c.490-430 BCE) devised a number of space-time paradoxes and a couple of these are well worth thinking about here.
First, there was the Paradox of Achilles and the Tortoise. We imagine Achilles racing a tortoise. He gives the tortoise a head start. To catch the tortoise he must first reach the point where the tortoise started – but by that time he reaches that point the tortoise will, of course, have moved forward. He must therefore now reach the point that the tortoise has got to. But again, when he does so the tortoise will have moved forward again. At this point it becomes clear that Achilles can never catch up, so the tortoise wins the race. How can that possibly be?
The second is the Paradox of the Arrow. A flying arrow is an excellent example of change because it demonstrates the motion of an object in space. Zeno pointed out, however, that if something is in motion then it must be in motion now, not in the past (when it was somewhere else) or the future (when it will be somewhere else). But at the brief instant of time which has no past or future the arrow can only occupy a space equal to its own size: it is therefore at rest. The same reasoning can be applied to all motion: movement and change are illusory. These idealists believed that the true nature of the world, its timeless perfection, is only evident to us when we ignore the evidence of our senses and apply strict reason. Aristotle and others have given compelling answers to these paradoxes but they express the flavour of problems that arise in philosophical discussion.
Parmenides (c. 485 BCE) is less easily dismissed. He also had a tricky question that he framed in the form of a prose poem. Here he argued that change involves something becoming something else in a transition we can only interpret as the reality of transition from future to present to past. For example, we treat the past as real when we say ‘it is a fact that I was driving my chariot to work this morning‘. But we also treat reality as applying to now. But if past events were real then they would be now, they would be present! More specifically we talk about non-present things as if they were real when we know that they are actually nothing; we treat events as ‘something’ coming out of the future, which is ‘nothing’, and ‘something’ in the present passes into ‘nothing’ in the past – but how can something become nothing? Where does it go? Variations of Parmenides’s concerns are still with us today.
We are tempted to say that of course things dont pass into nothing: a rock, for example, endures. But wouldn’t time still be passing while the rock endures? Parmenides pointed out that anything that endures must have temporal parts, those existing now, those that did exist, and those that will exist. But an existing rock surely cannot have non-existing parts? For Parmenides this is another way of demonstrating the illusion of change and time.
If you are puzzled by these paradoxes then you can look them up on the web and see the standard replies. Aristotle’s answers were not based on the evidence of the senses but on reason (Zeno and Parmenides considered the evidence of the senses as illusory, so Aristotle could not use sensory evidence to defend an alternative point of view). There are modern-day compelling answers to Zeno’s paradoxes but Parmenides has continued to mesmerise the philosophical mind because when we describe change we appear to commit ourselves to the reality of past and future while at the same time being tempted to deny their existence.
There is no doubt that in the attempt to reduce time to its simplest form philosophers have fallen back on the brute fact of change. We simply cannot imagine a change that does not require a temporal interval T(rd) and, most significantly, we measure time using movement and change so it is difficult, if not impossible, to dissociate ourselves from this aspect of time. The idea of an instant of zero duration is incoherent. Indeed, the argument that time is change itself is very persuasive and since Aristotle considered time to be way of thinking about the way events are objectively related he did not think that time was a kind of idea in the mind, it had reality in the universe, he was a relationist.
The conclusions we reach about time and its relationship to change will depend largely on a simple underlying assumption: whether time exists in its own right as a physical part of the universe with an identity of its own or whether it only exists as a relation between things. The physics of this question will be discussed in Time 6- Physical time.
Time-lapse photograph of an eight-ball break ‘Time is change’ Courtesy Wikimedia Commons
Semantics of change
First some tidying up around the linguistic edges. Change, like time itself, is a complex concept. As metaphor we frequently associate change with spatial rather than temporal change so we need to be on our guard for difficuties associated with making time space-like and space time-like. Then there is polysemy. We can, for example, differentiate between intrinsic and extrinsic change. When we say a poker ‘changes’ from hot to cold this is an actual change in physical properties of the poker but when we say a road changes from bitumen to gravel this is not an intrinsic change in the road surface but a change in perspective relating to someone travelling on the road.
Time as change, T(c), is undoubtedly semantically and conceptually the most complex aspect of time T(n). The relationship between change T(c), physical time T(*), absolute time T(a) and relational time T(r) is critical to our general philosophical conclusions. There are three major difficulties:
• T(c) entails the temporal categories ‘now’, ‘past’, ‘present’, ‘future’ and the temporal relations of ‘earlier/before’, ‘simultaneous with’ and ‘later than/after’ both as they relate successively to one-another and to events
• There is then the interrelationship between T(c), T(a), T(r), and T(*)
• Finally there is the determination of the subjective and objective elements of these various categories
Central to the philosophical discussion is whether or not we regard ‘now’ as a product simply of human perception or whether it has some objective basis in the world. ‘Now’ has a similar meaning to ‘present’ being difficult to define without circularity. However, ‘now’ does have a more urgent sense than we usually attribute to ‘present’ and this needs recognition in any semantic taxonomy. For the purposes of this account this distinction will be drawn more finely by defining ‘now’ as DF the indeterminacy of the future (unknown) giving way to the determinacy of the past (known): the coming into being of determinate reality (objective). Note that this definition is given in the present tense and also that it is not ‘the moment when’ now occurs. Now is our perception of time itself. ‘Now’ is the only semantic element of the semantic taxonomy (excluding T(a) and T(r)) that does not exist in T(ud). ‘Present’ is defined more innocuously as DF the current state of affairs or now as perceived and acted upon by humans.
Semantically ‘change’ is very closely related to the notion of ‘succession’. However, if we link duration T(ud, rd)] strongly to the notion of time, as most people would, then this diminishes the semantic impact of succession although there is clearly semantic overlap.
TIME, SPACE & CHANGE
Time has been described by at least one philosopher as the dimension of change (see Smart, Encyclopaedia Britannica). A change is something having incompatible properties at different times: that is, a variation over time in the properties of something.
Separating space & time
Philosopher McTaggart maintained that permanent truths, say, that on any weekday I am in bed at 6 am and at work at 8 am, do not demonstrate change. We are inclined to say that if I am in bed at 6 am and at work at 8 am on the same day then something must have changed. McTaggart stressed that on close inspection the two facts as presented were unchanging facts that could not constitute change itself. He claimed that change must involve changing facts about how things are now: it is only the present time (now) that keeps changing and this is the only true change: it is temporal change and we refer to it as the passage of time.
McTaggart noted that time and space are closely related and this shows up in our language. We even speak of a large space of time. What makes the dimension of time genuinely different from the dimension of space is that time seems to flow in some sense while the dimension of space does not.
Space and temporal intervals seem totally different. Maybe we can compare the two by making time space-like, and space time-like, then we will be comparing similar things. So perhaps it possible to tease out the difference between space and time by asking a precise question involving space, time, and change? For example: ‘What is the difference between poker 1 that is hot at one end and cold at the other, and poker 2 that is hot at first and cold later?’
We cantake a time-like view of the poker question by temporalizing space (describing it in terms of time, the spatial differences of the poker that is hot at one end and cold at the other) by answering:
(1) The difference is that poker 2 is hot before it is cold, but poker 1 is hot and cold at the same time.
This is true, but presents us with a contradiction. How can a poker be hot and cold at the same time? To resolve the contradiction it is necessary to point out the omitted spatial information, that the poker is hot in one place and cold in another. It is important to note that when we temporalize space like this it is immediately obvious because of the apparent contradiction.
Now we can spatialize time (describing the temporal difference as though it were a spatial one) by answering:
(2) The difference is that poker 1 is hot in one place and cold in another, and poker 2 is hot and cold in the same place.
This is also true but again there is a contradiction. How can the poker be hot and cold in the same place? The contradiction is resolved by pointing out the omitted temporal information, that poker 2 is hot before it is cold in the same place. Thus, when we spatialize time we omit the essential before and after relationship.
Endurantism vs perdurantism
In trying to get to the true nature of space and time we can accept that the poker has separate spatial parts; but can it, in a similar way, have separate temporal parts? Do objects have temporal extension in the same way that they have spatial extension?
The controversy endurantism vs perdurantism combines several separate debates including the following (at least): eternalism vs presentism; A-theory and A-properties vs B-theory and B-properties; differences between space, time and space-time; the true nature of physical objects and events; the true nature of change; and as usual, and most importantly, the question of whether we should treat time as a relation or an object. Endurantists maintain that all temporal parts must entail the entire poker (3D, temporal, A-series, presentist, Becoming) perdurantists (4D, atemporal, B-series, eternalist, Being) maintain that they do not.
Perhaps the most telling difference between 3-D and 4-D is that there is generally an entailment of presentism with 3-D, and eternalism with 4-D with their corresponding temporal and ontological commitments. We are once again talking about the A series (absolute) view of the world and the B series (relational) view of the world. 3-D is temporal: it uses language relating to past, present and future, the A series. 4-D is atemporal: it is timeless and removes all talk of tenses, the B series. For example, 3-D temporal part-hood is irreducibly relative to times. A 3-D’ist can either say “I am 2.2 m tall”, in which case it is assumed that what is said assumes 2.2 m tall now (tensed). Or she can say “I was 0.1 cm tall in 1945” (tenseless?). This is our everyday way of speaking. The perdurantist places no ontological emphasis on tensed language. Therefore since my space-time worm includes my height as being say 0.0001 m to 2.2 m the temporary properties of being 2 cm or 2 m tall are had simpliciter depending on which part of my space-time worm we are talking about. Both heights exist unconditionally and equally in my space-time worm. Being human I want to add the subjective now to locate the height in my time. Thus in the perdurantists tenseless world Socrates exists tenselessly as a part of the total space-time-scape while the endurantist says Socrates exist(ed) (wholly) because clearly he does not exist now. Just as here is not spatially privileged, so now is not temporally privileged.
For the perdurantist objects have temporal extension in the same way that they have spatial extension. We should think not of 3-D objects in time but of spatio-temporal objects in regions of space-time. Spatially, an object can have one property in one place and a different one at another and the whole object exist. But temporally we are tempted to say that the temporal whole exists all at once, unless we adopt the ontology of eternalism. The 4-D’ist must be temporally neutral and tenseless in the location of events and objects in space-time.
The difference between 4-D and 3-D can be seen in what they imply about change. In a world where substance is permanent, what changes is the properties or relations, or aspects of them? Endurance theory holds that change involves properties or relations coming into or going out of existence because if the past and future do not exist there is no place for them to come from or to go to. For perdurance the properties and relations never come into or go out of existence because if the future exists then the properties and relations already exist before the change takes place.
What is it that physicists are measuring when they measure time in the 4-D manifold? Which part of the space-time-scape are they measuring and why that particular piece – to locate that piece of time we must assume A-properties.
[The Block Universe is temporally closed, quantum mechanics is temporally open. To be explored later].
Semantics of ‘change’
Let’s try to isolate the idea of spatial change from that of temporal change. Over a distance (space) of 1 km a road surface might change from bitumen to gravel. This is a spatial change in the road, not a temporal change. Certainly the way the word ‘change’ is being used here follows common usage since we say ‘The road changes from bitumen to gravel’. Would we say that this is genuine change?
There are three important points to be made about this example that seem to distinguish spatial change from temporal change.
If we think of spatial change as the movement of a whole object from one place to another then this movement will take time; so itis not just a spatial change. So if we assume that spatial change of objects involves change(s) to spatial parts, not to the whole object then we might say that one spatial part of a road is bitumen, the other spatial part is gravel, one does not literally change into the other. But we should note that this is not the way we gnenerally understand change. Viewing the road from above in a helicopter one part of the road is gravel, the other is bitumen. We generally refer to spatial change when we have an externally defined direction from which to view the change – as when we travel along a road that changes from bitumen to gravel. The road was bitumen before it was gravel which is a temporal change.
In contrast, temporal change, such as that of a poker being hot before it is cold, involves the whole of the poker. (this difference is examined in more detail in ).
So we have two difficulties. Firstly, there is the word ‘change’ used as metaphor. Spatial change of the type bitumen to gravel on a road is not a change in physical properties (intrinsic change), it is better described with the word ‘difference’. The bitumen and gravel have remained the same. Indeed, because they have remained the same, we are surely entitled to say that they have not undergone true change at all.
When viewing change in this way we feel justified in claiming that the only true change is temporal change and that spatial change is far better referred to as difference (since nothing actually changes). Also the temporal before and after of temporal change implies ‘direction’ that is intrinsic (a part of the sequence of change). The before and after of spatial change has only extrinsic ‘direction’ (a direction that is imposed from without). This is a critical distinction: temporal direction, unlike spatial direction, is not a matter of human perspective. We can be assertive about this.
We can recognise the vagaries of language by asserting that spatial change as an object having different properties at different places (spatial change) is metaphor for real change which occurs when an object has different properties at different times (temporal change).
We can summarise the differences between temporal and spatial change as follows:
• Temporal change involves things changing their intrinsic properties. Spatial change is not intrinsic change
• Time has an intrinsic ‘before’ and ‘after’ (generally referred to as ‘direction’) while the ‘before’ and ‘after’ of space is extrinsic
• The ‘before’ and ‘after’ of temporal change is real change while the language of spatial change is ‘as if’ metaphor
• Spatial change is more appropriately referred to as ‘difference’
• When we spatialize time or temporalize space then essential information is lost
Our examination of the poker indicates that the isolation of space and time does not seem possible: it can only be treated as a kind of thought experiment. Although we can imagine spatial difference and temporal change as sepearate entities, especially in our everyday language, we can see under analysis that underlying everyday language there is not space and time but space-time. Everything that exists, exists ‘in time’.
Before and after
If the analysis above is correct then reference to ‘before’ and ‘after’ are intrinsic to time but extrinsic to space.
The nature of temporal change
Accepting temporal change as true change this can now be thought of in three ways:
1. Relations at times
The poker is hot before it is cold
This asserts that objects stand in different relations at different times in the same way that parts of the poker have particular spatial relations. This seems to deny change because at t1 the poker is hot (and that will always be true) and at t2 the poker is cold (and that will also always be true), so, when expressed in this way, there is no true change. Of course, we might impose true change by adding that t1 is before t2 (see discussion ).
2. Perdurance as temporal parts
The poker is hot at t1 and cold at t2
Change involves one temporally extended object (t1) having one part with one property (p1) (hot poker) and another temporal part (p2) with another property (p2) (cold poker). Change is treated the same way as spatial difference. Also the properties now attach to temporal parts: there is no whole thing (the poker) that changes its properties. Assumes eternalism: things exist equally over time. (see discussion)
3. Endurance as a whole
The poker is now hot and will be cold
The only properties the poker has are those that it has now, so it can never have incompatible properties. An object is wholly present at every moment of its existence. Assumes presentism; things only truly exist in the present. (see discussion )
ABSOLUTE AND RELATIONAL TIME AND CHANGE
If time is an object, it may well exist independently of change. If time is a relation then it only exists with change.
For the Relationalist time is change so time can only exist if there are objects with properties in spatial and temporal relations. McTaggart’s B series is relational because if, as B theorists maintain, the relations earlier than and later than involve primitive temporal relations, then the temporal relations are between things – time is not something in addition to those relations.
For the Absolutist, if time is independent of other things then it is equally obvious that it cannot be reduced to any of them, no matter how appealing that might be. If time (a) is independent of change then it cannot be change. Change then occurs in time and not vice-versa. Defenders of Absolute time maintain that although we may need change to measure time, that does not mean that it is impossible to have time without change. There may be a time that began earlier than our universe; time without events; time without objects; time with no beginning or no end – we simply do not know. If now is time itself (or change as McTaggart claimed) and we relate past, present and future to now, as we do in McTaggart’s A series, then we are treating it as an object: that is, as absolute.
McTaggart’s A series treats time as now, as an object, and therefore as absolute. McTaggart’s B series treats time as absent (a relation) since, according to McTaggart, it lacks true change as nothing relates to the truth-changing now. B-theorists who maintain that the B series entails primitive temporal relations must also assert time as a relation between things (not to now) and therefore relational.
When we ask a question such as “Can we imagine a world with time but no change?” it is important to remember that.
A material object can no more exist with zero duration than with zero length or breadth.
Strong arguments have been forwarded for the theoretical possibility of time and changeless worlds (see Shoemaker, ).
PAST, PRESENT, FUTURE
Most questions in the metaphysics of time lead to the questionable basis in reality of past, present and future (ppf). This does not, at first, appear to raise a problem. After all, we understand, think and act on the ideas of ppf without any practical difficulties or philosophical puzzlement. The key question, however, is what is it that makes a statement that something is ppf true or false?
Mellor (1998, pg.2) poses the problem by asking what makes a statement like ‘e is past’ true when it is true, namely when it is said at any time (t) later than e? He then offers our alternative replies that either e has the property of being past (A-theory), or e is earlier than t (B-theory).
But this is to pose the question in an unfair way because it both assumes the B-theory as a solution (the statement is true because t is later than e), and illustrates its detached perspective on the world (e and t are being observed by a third “timeless” party). The reason the statement ‘e is past’ is true at the time when it is actually said, is not because the statement was made later than e. The objective feature in reality that makes the statement true is that the time when the statement was made was later than e. We call that particular time the present, or now. (The time when it was made is a B-fact) BUT presentism.
In the context of this argument, presenting the problem in terms of statements is to superimpose the linguistic on the metaphysical: it is both unnecessary and confusing.
ONTOLOGY OF TIME
There are eight possible combinations in which past, present and future may be allocated existence or reality. What combinations may be called real or objective?
Only the following have been taken seriously:
• The past, present and future exist equally (eternalism)
• The past and present exist but not the future (past-presentism)
• Only the present exists (presentism)
• Only the present exists but the past is more real than the future
Eternalism will be dealt with in the chapter on Permanence. For the time being past, present and future are considered from the point of view of presentism.
Common sense tells us that the past is in some sense real. Fossils display to us the times when dinosaurs roamed the earth and the empty cup of tea in front of me indicates what has been going on in the more recent past. But our feeling is that only the present truly exists – or at least that it exists in a very special way. Is the immediacy of the present real or in some way a function of our conscious awareness?
If only the present is real then what are we to make of past and future events? For, if there are no past events, there can be no temporal series.The past is what has already happened. It is the totality of objects, their properties and spatiotemporal relationships that occurred in a present that no longer pertains. Nothing ever happens in the past. Things only happen in the present. What is objective – that which is real in the world outside our minds – is the objects, their properties and spatiotemporal relationships as they pertain now. Because many of the objects and relationships that occurred in the past, persist in the present there is a strong sense in which the past remains with us, so that we feel that it is real now. But it is not the past that is real now, only the persisting objects, properties and relationships.
We also feel that the past is with us because we can clearly recall past events. However, all memories of things from the past necessarily occur in the present and are subjective. A memory is, of course, a real and objective mental process in the present. But it is only a representation of something that has already happened, and it is not accessible to other people: it is the past event itself that is objective and real, not its representation in our minds. In other words, we cannot visit the past physically (objectively). We can only have subjective memories, recollections and imaginings of things that occurred, or might have occurred, in the past.
The past, we feel, no longer exists. However, there are facts that we believe about the past: that dinosaurs existed, as did Greek philosophers, ammonites, Elvis Presley and so on. Though not existing now, these facts have greater reality than assertions about the future. Can we argue that it is a fact that something in the future will be the case? Only the present exists but the past is more real than the future.
We need a clear and objective view of the past. It has already been noted that the process of aging is the lapse of time in the present. So is Socrates now over 1000 years old? Socrates does not exist so he cannot be aging, although we can calculate how long it is since he existed. There are some dinosaur bones that exist now and they are tens of millions of years old and still aging.
We feel that we have conclusive evidence of events that occurred in the past. Using tensed language we say that dinosaurs existed in the past. To capture a sense of the reality of past events we could say that dinosaurs exist, but they do not exist now. The future is what has not yet happened .We cannot say that anything exists in the future.
PRESENT AND PRESENT EXPERIENCE
Intuitively all our experience takes place in the present: this is the common sense view of the world. We catch trains, set watches, watch sporting events world-wide and view the ebb and flow of stock markets and currency values as a world community. These are all public events that occur in a public now that is accepted universally without question. We believe that biological species and the universe itself has reached a particular historical phase of evolution that we refer to as now. If we are deceived about the reality of now, then we are all deceived together. There must then be a collective “subjectivity”.
Direct awareness of things and events seems to justify their being present, and that earlier events that we remember are past. But when we look down a telescope we see past events, things that happened light years ago, as present. So can we be deceived – is presence a matter of awareness, or our human perspective or some other subjective influence?
The B theory cannot account for the following aspects of the presentness of events:
• We sense that we are at a particular stage in the evolution both of the universe and biological organisms that we call now. There is no evidence of any future – we are not visited from people of the future or have any kind of experience of things in a time beyond now.
• There is a completely unquestioned world-wide communality of now as instanced by an agreed synchronisation of, for example, watches, sporting events world-wide, and the ebb and flow of stock markets and currencies. If these are illusory or subjective then they are to humanity as a whole.
• For the B theorist the present is simply an indexical (token reflexive) relationship to statements. When we refer to the present or now we simply mean “simultaneous with this utterance”. But there are many occasions that we regard as present when nothing is uttered.
• B theory relates awareness of A-times to dates but we may be aware of the present regardless of any dates
It should be noted, however, that for the B theorist presentness is a feature of our awareness rather than a feature of events: we must distinguish between our experiences and our present-tensed beliefs about them.
Although “E is present” cannot be translated into tenseless language, what makes it true is that it occurs at the same time as the awareness of it!?
HERE AND NOW
‘Here’ is the spatial analogue of ‘now’. Just as A-times relate to now, so A-places relate to here: and just as B-times do not relate to now but to each other, so B-places do not relate to here but to each other. It is notable that although many people believe in temporal A-facts (e.g. that an event itself has the property of being now), no-one believes in A-places (e.g. that Melbourne itself has the property of being here). Things and events in space are literally neither here nor there.
We have isolated three meanings of present – do these have spatial analogues?
The presence of experience – our awareness that all our experiences and actions are present (same as below?)
Specious present (now) – my now, the perceived immediate moment appropriate to human action = my here.
Contextual present (now) – contextual now i.e. present second or present century = contextual here i.e. the town or planet that is here.
Present (now) – the physical temporal boundary between determinacy and indeterminacy (mind-independent), the true A-time of an event (what is the true A-time of a soccer match?) – no spatial analogue
We need to determine similarities and differences between here and now, as this may be a significant difference between space and time – now being associated with temporal change and there being no objective here? What is the relationship between here and now? Are they completely congruent? If they are then whenever we make an assertion about now then there should be an equivalent assertion about here.
Theory of space assumes hereness and thereness are mind-independent properties of objects over and above their locations and the fact that the objects are near the places we occupy Hereness and thereness are mind-dependent properties. All that exists are objects, their spatial locations and relations to other objects. Our experience of space is just our experience of these locations and relations
Presentness is something we experience in addition to an event’s occurring: it is not simply the occurrence of an event, or the simultaneity of the event and our experience of it. We do not know what it is but we know what it is not, and we can sense it. It is something we experience in addition to the event itself which tells us that the event is now. B-theorists say that this is precisely what A-theorists deny. When we experience an object as here, do we experience it as more than the object and its nearness to us? If this were all we experienced then we would not know the object was here. Rejected. Hereness is not something extra.
We cannot choose the times we can be at We can choose the places we can be at
We feel that the present exists in an objectively privileged way. Past and future do not seem so important. We do not feel that here is spatially privileged.
Past and future events are not equally real. Temporally distant events do not occur at the same time as temporally near ones. Objects elsewhere are equally real. Distant objects exist at the same time as near objects.
Present is characterised by a changing set of events – the feel of movement Here has no sense of change or movement. If we move from place to place we would not adopt the A theory anyway
The space analogy suggests no experience beyond simultaneity is needed to experience presentness
The ontology outlined so far is called presentism. Presentism is the view that only present objects exist, all other objects are unreal. An inventory of all the things that exist would not include any non-present objects. The only things that exist are those that presently exist. Associated with this view is the assumption that time is not like space.
We want to say that it is not that the objects of the past do not exist but that they do not exist right now. This is not possible because the presentist wants to say that the set of all that exists changes over time.
The presentist position is that of common sense, the position that most people would take when first asked their view on what exists. However, such a position has many problems because much of our language is devoted to things in the future and things in the past, namely non-present objects that the presentist claims do not exist. It has already been observed that most of our mental activity involves an interplay of anticipation and recollection. When our mind is focused on the present we are hardly aware of its activity as when we are playing a competitive game of table-tennis, driving on a dangerous road or watching a thrilling movie.
Problems for the presentist include:
• There can be no singular (specific) propositions about non-present objects. For example the statement “Socrates was a philosopher”. Presentism must maintain that when Socrates was no longer present, singular propositions about him must also go
• If there are no non-present objects then no-one and nothing can stand in any relation to any non-present object. I cannot be my great grandfather’s grandson. For the same reason nothing today can stand in a causal relation to something in the past – my feeling seedy because I drank too much last night for example
• There can be no propositions about non-present times
• Presentism is possibly in conflict wit the theory of relativity. The STR demonstrates that simultaneity with here and now does not pick out a unique set of events across the whole of space. So if only the present exists then it may be thought that you must shrink what exists to what is going on here and now – that nothing exists outside your present spatial location as well as your temporal location
The presentist and eternalist agree that Socrates does not presently exist and that he existed. However, the eternalist would claim ‘There is such a thing as Socrates, which does not exist at the current time’. According to presentist there simply is no such object as Socrates. In other words for eternalists and presentists what exists and what is present do not amount to the same thing. They agree over what is present, but not about what exists. Non-presentists can argue that while Socrates is not present right now, nevertheless he exists now.
If the past and future do not exist, then the presentist must explain the sense in which statements about the past and future are true.
Presentism and modality
The debate about presentism vs eternalism is similar to the modal debate about actualism (everything that exists is actual) vs possibilism (non-actual things exist). Actualism is the philosophical position that everything there is, everything that can be said to exist in any sense, is actual. But that there is nothing beyond actuality. This stands in contrast to possibilism which includes things that are non actual but which could have been. Possibilism is sometimes accepted as referring to theoretical abstract objects which actually exist. They may be termed mere posssibilia or contingently non-actual individuals.
Actualists would generally be presentists and assert that the actual world is congruent with present time.
It may be argued that time is fundamentally like modality and unlike the dimensions of space. In logic the modal operators “it is necessary that” and “it is possible that” work in the same way as the tense operators “is”, “was” and “will”. Also abstract worlds and abstract times are similar and finally, according to the presentist, the past and future are as unreal as the merely possible. There is no reason to think that being real at a remote temporal location is like being real at a remote spatial location.
Modal realists have non-actual objects in their ontology (Lewis), while the ontology of modal actualists is restricted to the objects in the actual world (Plantinga, Adams). For these two positions to be opposed, both must agree that what exists and what is actual are not the same.
Presentism and change
Properties past, present, futureMcTaggart’s A series gains much of its feeling of true change by the passage of events from future through present to past. He says “every event must be past, present or future”. But how can an event be future except in an anticipating mind? And, if the future does not exist how can any event have the property “future”. Nothing real can have the property of being future because the future, no matter how apparently inevitable, does not yet exist; it has not yet happened. In short, nothing can pass from the future to the present. The future is a human (sentient being) projection – put simply, an anticipation. There can be no properties of past, present and future are simply a nonsense.
PRESENTISM VS ETERNALISM
In contrast, eternalism maintains that time is like space. For space there is no special status given to things that are here. Things in other places, say London and New York, are just as real as those here in Melbourne. By the same token, for the eternalist there is no special status given to things that are present (now). So, things exist in space that are not here, and things exist in time that are not now: these things are said by the eternalist to be merely past and merely future entities. They exist now, even though they are not currently present and they would be on the inventory of things that exist. So to say that things are merely past or merely future is to assert the eternalist position. Past, present and future, the eternalist argues, are an anthropocentrism that leads us to false assumptions about the existence of objects. This is because we emphasize the non-existence of the past (and future). Eternalists point out that just as here is a relative place, so now is a relative time. When we say there are no trees here (the emphasis is on place) we don’t mean that there are no trees – after all there are quite likely to be trees somewhere. Similarly when we say “Dinosaurs do not exist” what we mean is “Dinosaurs do not exist now” (the emphasis is on time) – then it is possible that there are dinosaurs somewhen. The grammatical omission of the now distorts our interpretation of what the sentence means and therefore alters our understanding of what exists and what does not exist.
The future is what has not yet happened. We can imagine things that could not happen in the real world there also appear to be many things that are possible; things that are very likely and others that seem inevitable. Our anticipation of the future, coupled with the predictability and apparent inevitability of many events give us the impression that there is much in the future that is fixed or determined. No matter how inevitable events might seem, the unexpected is possible. The future has not yet happened. No matter how inevitable things seem in the future they only happen in the present. Nothing happens in the future and nothing is inevitable. All of the experiences we have of the future must be subjective and, of course, they must take place in the present. The only objective experience is our experience of an event itself, as it happens.
According to the B theory past, present and future exist equally and future tense statements have a truth value – the principle of bivalence (that every statement is either true or false) remains intact: future facts are truth-makers for future tense statements.
For the A-theory there are no future facts – so what are the truthmakersfor future tense statements: present facts? In which case determinism seems to follow? But it is possible to deny that future contingents have a truth-value because it means that every statement can be either proved or disproved, which is false. This is sometimes called intuitionism. Does this escape the argument?
If we hold that the future does not exist then clearly durations set into the future are human projections based on previous experiences. For example, if I have a birthday X days ahead based on a calculation made today, then I can say that the temporal interval will be 1 day less at the same time tomorrow. After 1 day has passed the interval will be 1 day less and the day of the birthday will be getting nearer based on my knowledge and experience of calendars and dates. Two important points follow:
This is lapse of time in the present (nothing is getting shorter or closer, or further away)
• Neither the birthday nor the durationsl are moving in any sense, this is metaphorical language, but more importantly neither the birthday nor the temporal interval (as extended time) real in any sense, they are anticipations, mental constructs. They are real in minds only.
But the birthday really is X days ahead! There is something in my mind AND surely something in reality? All we have in reality is X days worth of time lapse in the present.
There is no event later than a present event.
For the eternalist, past, present and future exist equally. However, in the world of the presentist and common sense, the future does not exist. Certainly there are possibilities and probabilities (possibilism) even apparent inevitabilities (fatalism), but events cannot exist in the future or have the property of being future in any meaningful way.
We do not perceive future events because we can only perceive earlier events as memory in the now – this is a causal relation. But maybe this causal relation is mind-dependent, our particular human perspective from within time. Could or does the future affect the past?
To say that the future does not exist means we must abandon all talk of the past and future. There is neither a McTaggart A or B series, A because there are no such things as future events to have the property of being future – we cannot talk of what we will do next year? At most the future is a set of objective possibilities, some of which may happen.
Denying that future events exist does not make judgements about the future meaningless. Judgements may be true or false then depending on whether or not they are instantiated.
All statements about the future must be general because they are about the merely possible. It is ony actuality, th forse of existence, which produces a discrete unity. Future must be general, past may be singular.
Both deliberation and action are causative in relation to the future. Not all existence is the outcome of necessity (determined?)
Do future contingents have a truth value – or not yet have a truth value – or no truth value at all. Do truth values change over time?
The agents concept of time is modal
Possibility -> actuality -> necessity
What can we say about future contingents (events that have not yet happened and are causally undetermined)? For example, if we say “tomorrow there will be an earthquake in the South-east pacific”. How are we to judge the truth value of such a statement?
• If there was an earthquake the following day then it was true
• It cannot be true or false because there are no facts to which the statements can correspond
Now, if we say “tomorrow there either there will be an earthquake or there will not be an earthquake”
What is the truth value of this statement?
• One of the cases must be true so the statement is true
• If neither of the possibilities can be said to be true or false then how can the two in combination be said to be true?
• If either is true then are we committed to fatalism? Logical determinism assumes that every proposition about the future is either true or false according to the law of excluded middle which says that all statements must be either true or false in contrast to the posoition asserting that nothing can be said of the future. It seems that the law of excluded middle robs us of our freedom of choice
This problem has spawned several logics including 3-valued logics and chronological or tensed logic.
If the past and future do not exist then we must explain the sense in which statements about the past and future are true.
• We remember the past but not the future
• We think we can change the future but not the past
• We assume in the present we are performing actions that add to the past but not the future
• The future contains possibilities in a way that the past does not
Statements about the future must be general. Statements about the past may be singular.
“What will happen will happen” is a harmless tautology
“What will happen will happen of necessity” amounts to fatalism
There are three forms of possibilism.
1. Those things that exist are actual – they have an intrinsic ontological property, existence or actuality. A possibilist is someone who believes that there are things that are not actual, indeed the actual is only a small proportion of what there is. This is a distinction between what there is and what is actual. The sort of things that are not actual are unborn children, non-actual brothers and sisters and so on.
2. It may be claimed that there is no difference between what is and what exists and therefore to say “there are things that don’t exist” is nonsense. The possibilist then agrees that everything there is exists, but that not everything that exists is actual. This seems to be a word game in which is has been renamed existence and existence has been renamed actuality. The possibilist has simply replaced two modes of being with two modes of existence – actual existence and possible existence. The possibilist will believe this is acceptable, others will not.
3. An alternative to 2. is that being and existence are the same but there is no special ontological property or mode of being that separates merely possible objects from actual ones. Here, again, actuality is different from existence. Actuality is not a property but a relation where things are spatially or temporally related. Then, non-actual things are simply things that occupy worlds other than ours – things that exist but are spatially and temporally unrelated to us. The semantic corollary is that “actual” is indexical, its reference being given by the context of its utterance. “Howard actually exists” then means that Howard occupies the same world as the speaker.
Thus 3., like 2., acknowledges the comprehensive character of existence but without primitive properties or existential modes of actuality.
A fatalist thinks the future is fixed or determined in the same way as the past – that there is nothing we can change. That, for example, given the conditions now in their entirety, there is only one way in which things can happen next – this in turn producing a situation from which it is not possible for anything else to happen.
]][Before then it is only an anticipated date or event. After the event it moves into the past but exists only as a memory, even though I can always state with great accuracy how far back that birthday occurred and I can remember objects and events that truly existed at least at that time. Assuming the event of my birthday only truly exists when it is happening but does not truly exist before or after the day on which it occurs, how can I speak of it approaching or receding? (Do events exist or are there only things that change?) See past, present, future. So, does only the present truly exist? Is there any sense in which the past can exist?]]]
Events, time or whatever comes out of what does not yet exist, passes through what has no duration and moves into what no longer exists. Augustine’s solution was to conclude that the future is anticipation and the past, memory. In other words past, present and future have no objective reality. He asked “If the future and past exist I would like to know where they are”. He was spatializing time. We must beware of diagrams and spatial metaphors.
Is the division of time into past, present, future and the tenses was, is and will be (A-series) with events approaching and receding (flowing) truly part of the objective world, or is it a construct of the human mind?
Perhaps we can represent the world simply in terms of before and after and at the same time (B-series statements) without any need for tenses. This is the timeless (eternal) language of mathematics and logic. We can argue that when we say that the Olympics was one year ago, this can be stated with no loss of meaning in terms of B-series language, not in terms of pastness, presentness and futurity.
Defenders of A-series statements and flowing time as objective are called process philosophers (Whitehead, Bergson) or, perhaps, in a modern form presentists (Sider), while defenders of the B-series as the only objective expression of reality are defenders of the Block Universe or eternalists (Williams, Armstrong, Smart, Grunbaum, Quine) and more recently (Mellor, Price). The latter point out that the present has no special objective status and there is no objective flow of time. Tensers claim that the B-series does not capture the essence of time as it does not adequately express change: it does not have a direction and therefore is no different from a spatial series. Only the A series generates true temporal relations. B series has primitive temporal relations while A series does not (Oaklander).
It undeniably seems as though time flows. If past, present and future all exist equally then present events must have some characteristics (such as a relation or property) which make them special and distinguishable. But then if we were to imagine transposing the events-at-times of the 3D universe (said to be dynamic or flowing) into events-at-temporal-locations of a 4D block universe (said to be static) there would be no difference. Each moment would produce a space-time slice and that would include slices of our mental states (which would be just the same as those in the 3D universe) – so there would be no difference.
NOW OBJECTS EVENTS
ACTUAL MENTAL PRESENT END/PERD PRESENT END/PERD
PRESENTISM X X X
ETERNALISM X X X
SPENCERISM X X X
Something does not become present in the same way that it becomes hot
We cannot defime memory without reference to a past event and we cannot define the future wothout reference to a future event – circular.
EVENTS AND THEIR ONTOLOGY
To define the universe in a sentence is not a simple task. However, let us define the physical universe as the totality of objects, their properties and their spatio-temporal relationships. These relationships are constantly changing in time (ud). An event is DF a particular set of objects and their spatio-temporal relations and properties over a designated duration. We could designate a childbirth, a collision of subatomic particles and a football match as three different events. So, for example, a football match is the changing properties and spatio-temporal relations of objects associated with the football match for the duration of the game. This is the objective football match. There are also many subjective aspects to the match such as: the many people looking forward to it; imagining the match approaching from the future; the thrill for individual members of the crowd when their team scores a goal and so on. An event may have a subjective component (e.g. my enjoying the goals and the win at the end) and an objective component (the spatiotemporal relationships and properties of the players and other objects related to the game over the duration of the game).
Is change a change in events, or a change in spatio-temporal relationships of things. Can events change in any meaningful way? Do events exist in any meaningful way?