The passage of time is an inescapable feature in our experience and our lives. Now that I am in my seventies and see photos of myself when I graduated college, got married and had young children, I am keenly aware of time passing. Yet, what Augustine famously said of time may be equally said of the passage of time from which it is inseparable: “What, then, is time? Provided that no one asks me, I know. If I want to explain it to an inquirer, I do not know.” When we begin to reflect we soon realise that there is something puzzling about time passing. The ordinary notion of passage or passing, is a spatial notion, and not a temporal one. We talk of passing through small towns on our drive through upstate New York, or passing a car on the highway, or passing a football 50 yards for a touchdown. These are all examples of something moving through space. However, when something or someone passes or moves through space it also moves through time. Thus, if time itself passes, and our model is spatial, it too would have to pass through time. In that case, we would need a second time-dimension in which time passes. Presumably, the second time-dimension would also move through time, requiring the need for a third time-dimension in which the second time-dimension moves and so on indefinitely. This doesn’t seem right, so we should not think of events in time passing in the way we think of objects in space passing. How then should we understand the passage of time?
Although we may find it difficult to say precisely what the passage of time really is, we certainly are aware of its presence in our experience, language and thought about the world. Consider, for example, our experience of events moving from the future into the present and then receding into the past. The writing of this article when I first conceived of it was in the future, then when I began to write, it became present, and after completing the writing, it became past. This common experience is reflected in language using grammatical tenses when I say I will write this article tomorrow, I am writing the article today, and I wrote it last week. Such language has been construed as implying that the event or action of my writing first has the property of being future, loses it and acquires the property of being present, and subsequently, my writing has the property of being past. On this view, call it the transitory temporal property view (“property view” for short), the past, present and future exist, and temporal passage consists in events or times changing their temporal properties of futurity, presentness and pastness in that order as they transition from the future to the present and then from the present into the more and more distant past; a process called “temporal becoming.”
Augustine in the Confessions, eloquently argues for the existence of the past, present and future as follows:
“Who will tell me that there are not three times, past, present, and future, as we learnt when children and as we have taught children, but only the present, because the other two have no existence? … Where did those who sang prophecies see these events if they do not yet exist? To see what has no existence is impossible. And those who narrate past history would surely not be telling a true story if they did not discern events by their soul’s insight. If the past were non-existent, it could not be discerned at all. Therefore, both future and past events exist.”
However plausible the property view appears to be, there is another way of understanding temporal passage that is equally plausible, if not more so. We intuitively believe that what has not yet happened, but will happen – the future – does not yet exist, and that what has already happened – the past – no longer exists. In other words, our commonsense view of time is that only the present exists, and that the past and future are, to use the words of A. N. Prior, “two particular species of unreality”. On this view, call it “presentism”, there are no properties of futurity and pastness since there are no future or past events or moments of time to exemplify them. For the presentist, the passage of time consists in events transitioning from non-existence to existence to non-existence again. For example, my writing this essay passes through time by first not existing, then coming into existence, and then ceasing to exist; a process called “absolute becoming”.
Although these two views of passage are intuitively plausible to unreflective common sense, they are incompatible. For if, as the presentist maintains, only the present exists then it cannot also be the case that the past and futureexist, as the property view claims. Furthermore, if temporal passage consists in events/moments existing through a change of temporal properties, then the passage of time cannot consist in events/moments changing their existential status. So, presentism and the property view are mutually exclusive, but things are worse than that since there are reasons for claiming that both intuitive views do not provide an adequate account of temporal passage.
On the temporal property view, my writing this essay passes through time by first existing in the future, and then flowing through time until it becomes present, then immediately becomes past and subsequently recedes forever further into the past. One problem is that my writing happens over a relatively short period of time, and has a relatively short duration. Yet, if the event passes from the far future through the present and into the distant past, then it exists at all those times and so has an exceedingly long duration! Moreover, if an event changes its temporal properties as it flows through time, we are once again faced with the original question, what constitutes the passage of time through which events flow? To say that time passes when temporal individuals (or moments of absolute time) change their temporal properties in a second time-dimension leads to precisely the same difficulties regarding events passing through time: moments of time have an exceedingly long duration and a third time-dimension is needed for moments of the second time-dimension to flow through.
For the presentist, the passage of time consists in the coming to be and ceasing to be of events or moments at successive times or NOWs. Thus, my current (or present) writing of this essay does not exist at any earlier time or past NOW, it does exist at the present time or NOW and it does not exist at any later time or future NOW. Since earlier/later than are temporalrelations that obtain between times or NOWS at least one of which is not present, they are an anathema to the presentist view that only the present (time or NOW) exists. However, without the succession of NOWs the passage of time, as the presentist conceives of it, would be restricted to a single time or NOW and that is impossible. My writing this essay cannot not yet exist, come into existence and no longer exist at the same time or NOW.
The common problem with the property view and presentism is that they can explain the passage of time only by appealing to the times or successive NOWs at which events or moments change their temporal properties, or come into existence and cease to exist. Thus, these views assume the existence of time in attempting to understand the passage of time. We are left to wonder what then can be done? Is there a better way of understanding temporal passage? I think there is, but to do so we must recognise that the passage of time is timeless.
To begin to see what is involved, suppose we return to the phenomena by which we come to know the passage of time. When I was 16, I decided that I wanted to get a Ph.D. in philosophy. It was, at the time, a goal for the distant future. I realised that goal 11 years later and many decades after that I remembered that accomplishment. Another instance of knowing that time has passed occurs in planning on being on time to a meeting at 1 o’clock. I check my watch and see that it is 12:30; look at it again, and see that it is 12:50; then, when I see that it is almost 1, I get up and go to the meeting. These experiences reflect that time has passed, since in one case I can reflect on successive changes along my life’s way, and in the other I can see that the position of the minute hand on the watch has changed. There is, however, a more immediate way in which we know that time is passing. This occurs when we are directly aware of passage, when we experience change in a single act of awareness. For example, if we look at a second hand of a watch or a flickering flame, we see the moving second hand at one place on the watch before the other, or one flicker of the flame occur before another in a single act of awareness. These are cases where we experience two stages of the second hand or flame occur in succession, one earlier than the other, and in so doing we are directly aware of a temporal transition or passage from one stage to the other. Similarly, when we hear the successive notes of a tune or feel the successive taps of a physician on our abdomen during a physical, we directly experience that time is passing.
My proposal is that an appeal to the direct experience of succession in a single act of awareness is consistent with founding or grounding our most basic experience of the flow or passage of time on mind-independent temporal earlier/later than relations alone; a view I will call the temporal relational theory (“R-theory” for short). On the R-theory, the commonsense belief that time passes is to be understood in terms of the relation of succession between earlier and later temporal objects. Thus, the passage of time consists in the succession of events throughout the history of the universe; one event – the earlier – being followed by another – the later.
Although the R-theory understands and grounds the passage of time – the flow and transition from one event to another – by appealing to the mind-independent temporal relation of succession, there is a sense in which the passage of time is mind-dependent. For, the passage of time also refers to the phenomenon of temporal becoming or the “movement” of events from the future to the present and into the past, and though there is a close connection between these two temporal phenomena, there is an important difference between them. On the R-theory temporal becoming is dependent on the perspective from which events are viewed and the successively changing psychological attitudes we have toward the same event, whereas the passage from earlier to later events is not so dependent. When I am consciously anticipating a later unpleasant event, say, an upcoming root canal, the event is future and I may think of it with dread. Later, when I am consciously perceiving or otherwise experience the (roughly simultaneous) unpleasant event, the event is present and I am experiencing it (with, perhaps, some distress). Finally, when I am consciously remembering the earlier event I feel relieved that it is over or past. Thus, temporal becoming – events moving through time from the future to the present and into the past – is a change, but it is a change brought about by the succession of different psychological states in me. Since it is a change of mental states toward the same object, temporal becoming is mind-dependent, but it is founded on the mind-independent relation of succession.
The passage of events or objects from the future to the present to the past, is not a change in the temporal characteristics of the event in question, as the property view maintains, but a change in the psychological attitudes of a single conscious mind toward the same event, each from a different temporal perspective. Thus, on the R-theory, apart from consciousness nothing is really or intrinsically past, present or future. As Bertrand Russell put it in Mysticism and Logic: “Every future will someday be past: if we see the past truly now, it must, when it was still future, have been just what we now see it to be, and what is now future must be just what we shall see it to be when it has become past. The felt difference of quality between past and future, therefore, is not an intrinsic difference, but only a difference in relation to us: to impartial contemplation, it ceases to exist.”
Nor does temporal passage consist in absolute becoming as the presentist conceives of it, namely, as a transition from non-existence to existence and vice versa. On the R-theory, temporal transition or passage, is understood in terms of succession and if one thing succeeds another they must both exist. For that reason, becoming, understood in terms of something emerging and passing away, is not a matter of successively changing with respect to existence. Rather, to paraphrase Erwin Tegtmeier, to emerge is to have a beginning and to pass away is to have an end. The beginning of a thing is its earliest temporal stage and the end is its latest temporal stage. This non-existential (non presentist) view of becoming is compatible with the relational theory that nothing can acquire and shed existence.
On the R-theory, it is time itself, construed as temporal relations and the facts those relations enter, for example, a is earlier than b, that constitutes passage. Recall, the problem that plagued the property view and presentism is that they assume the existence of time to explain time’s passage. The relational view avoids that problem by claiming that the ground of the passage of time is succession; a relation between objects that does not itself exist in time. To be in time is to be a term of a temporal relation, but on the R-theory, temporal relations are timeless since it makes no sense, and is ill-formed, to say that the earlier than relation is earlier than or later than anything. Moreover, even though the R-fact that, say, a is earlier than b does not change, it is not the case that the fact is permanent in the sense that it always exists, or exists at every time. For it too is timeless, since it is not a term of a temporal relation. Thus, since the essence of time is passage, the foundation of which are timeless temporal relations and timeless R-facts, we may conclude that the relational analysis of passage does not succumb to the difficulties facing presentism and the property view. Although time contains temporal passage, the passage of time and indeed time itself, are timeless.
To countenance temporal relational facts and temporal relations is crucial to providing a ground for the unchanging (timeless) character of time as a whole, and the dynamic flow or passage of time within it. J. S. Mackenzie, in an encyclopedia entry on “Eternity”, stated the relation between the timeless and the transitory aspects of time when he wrote, “There is no time outside the process. Hence the process as a whole might be said to be eternal though every particular part in it has a place in time. … The process, when we thus conceive of it, is not in time, rather time is in the process. Time is simply the aspect of successiveness which the eternal process contains.”
It is not surprising that the sentiment Augustine raised about time in the fourth century, Russell raised more generally about philosophy in his lectures on The Philosophy of Logical Atomism in the twentieth century:
“Everything you are really sure of, right off, is something that you do not know the meaning of, and the moment you get a precise statement you will not be sure whether it is true or false. The process of sound philosophizing, to my mind, consists mainly in passing from those obvious, vague, ambiguous things, that we feel quite sure of, to something precise, clear, definite, which by reflection and analysis we find is involved in the vague thing that we start from, and is, so to speak, the real truth of which that vague thing is a sort of shadow.”
Those ambiguous beliefs that we feel quite sure of, upon reflection and analysis, are often seen to be incompatible and give rise to puzzles. Surely the passage of time is a prime example of what Russell is talking about. Perhaps, this article moved you ever so slightly toward the “real truth” of which the vague ordinary notion of temporal passage is just a shadow. Even if, as is more likely, you are not sure whether my conclusions are true or false, I hope that your interest has been piqued about the passage of time.