Back in the 4^th century, St. Augustine asked the question, “What, then, is time?—if nobody asks me, I know; but if I try to explain it to one who asks me, I do not know.” [1]  Until recently, I never gave much thought to the question of time.  Most of my career as an academic was devoted to sociological rather than philosophical questions, except for questions of a methodological nature.  Only after I retired from teaching sociology and began to read more outside my discipline did I become aware of the great diversity of views on the nature of time.  Some scholars regard time as close to the very essence of reality, while others dismiss it as something of rather minor importance.

As an example of this diversity, let me start with two early twentieth-century scholars, Bertrand Russell and Alfred North Whitehead.  In their early careers, they were collaborators, co-authoring a major contribution to mathematics and logic, the Principia Mathematica.  Later they went their separate ways intellectually and came to disagree over many philosophical issues, one of which was time.  Russell said, “To realize the unimportance of time is the gate of wisdom….There is some sense—easier to feel than to state—in which time is an unimportant and superficial characteristic of reality.  Past and future must be acknowledged to be as real as the present, and a certain emancipation from slavery to time is essential to philosophical thought.”  Whitehead, on the other hand, became one of the founders of what is often called “process philosophy,” for whom time is of central importance.  He said, “Apart from time there is no meaning for purpose, hope, fear, energy.  If there be no historic process, then everything is what it is, namely, a mere fact.  Life and motion are lost.”

Here are some other quotations that suggest the diversity of opinions about time:

The Moving Finger writes; and, having writ,
Moves on: nor all your Piety nor Wit
Shall lure it back to cancel half a line,< /br> Nor all your tears wash out a Word of it.

—Omar Khayyam

[Khayyam’s metaphor of the writer suggests that the flow of time is a creative process.  We can make a sharp distinction between what is not yet written and what is already written indelibly.  On the other hand:]

The flow of time is clearly an inappropriate concept for the description of the physical world that has no past, present and future.  It just is.

—Thomas Gold

For us believing physicists, the distinction between past, present and future is only an illusion, even if a stubborn one.

—Albert Einstein

The history of natural philosophy is characterized by the interplay of two rival philosophies of time—one aiming at its “elimination” and the other based on the belief that it is fundamental and irreducible.

—G. J. Whitrow

In this last quote, the word “elimination” is in quotation marks, suggesting some uncertainty about how far this elimination really goes.  Those scholars who minimize the importance of time don’t stop talking about it altogether, but they do leave out of their conception of time ideas that other scholars consider essential, in particular a meaningful distinction between past, present and future.  To see how this can happen, let’s start with some simple ways that we measure time.

Mechanical time vs. process time

The metronome is a simple device that musicians use to keep time.  We can see it move and hear it clicking.  But all we are observing is a cycling back and forth.  We can call one direction forward and the other backward if we like, but that would be arbitrary. There is nothing in the metronome’s action to tell us that we are moving forward in time, or that the future is any different from the past.  We find a similar limitation in a clock.  A clock has a somewhat different kind of motion, in that the hands always move in the same direction, which we call “clockwise.”  Nevertheless, it is very similar to the metronome in having a cycle that always brings it back to where it was before.  Every 12 hours the hands return to the same position they occupied 12 hours earlier.  Repetitive cycles of this kind are also found in our natural ways of marking time, such as the rotations of the earth that we count as days and the orbits of the earth around the sun that we count as years. To measure time more precisely, scientists rely on much faster oscillations, such as the oscillations of electromagnetic fields, but these too are repetitive cycles.

What I want to emphasize is the symmetry of these temporal cycles.  By symmetry I mean the similarity between the past and the future, as long as the cycle continues.  There is symmetry with regard to direction, since things always go back to where they were before, instead of moving on to something new.  There is also symmetry with regard to certainty, because the cycle’s future is just as certain as its past as long as the cycle continues.  As long as the clock keeps running, there’s no doubt about where it must go next.  The kind of time we are talking about here has been given many names: symmetric time, periodic time, recurrent time.  We can also call it mechanical time, because the symmetry displayed by clocks is the same kind of symmetry we expect of machines in general.  When you go out to the parking lot and restart your car, you're looking for repetition of past behavior, not novelty.  You expect the engine to turn over and keep turning over repeatedly until you turn it off.

But this mechanical conception of time does not include everything that we find in our experience of time.  Our experience of time is not entirely symmetric with regard to direction or certainty.  In our experience of time, we have a sense of irreversible direction, a sense of moving forward in time never to return to a previous state of affairs.  We are always moving away from what has been and toward what has not yet been.  We also have a sense that the past and the future are distinctly different in certainty, with the past being more certain than the future.  We assume that we cannot change what has already happened, but what happens next is to some degree up to us.  In everyday life we make both of these assumptions, that time is irreversible and that it is open-ended. These assumptions are what David Ray Griffin calls “hard-core commonsense” assumptions without which our lives make no sense.  This conception of time, the idea of time as an irreversible movement from a certain past to an uncertain future, has been called asymmetric, non-recurrent, or process time.  We can also call it lived time, since it is the time that gives meaning to every moment of our lives, regardless of what time it is according to the clock.  It involves creative becoming, not just repetitive being.

The debate over time is largely a debate over whether this process time is to be taken seriously.  Is process time real, or is it a misconception that we should eliminate from our understanding of time?

Scientific resistance to process time

Process time is taken for granted not only in our everyday lives, but in many academic disciplines, especially the social sciences and humanities.  Try to imagine the study of history or developmental psychology without the distinction between the finished past and the open future.  On the other hand, many scientists have questioned at least the open-endedness of process time.  Strict determinists have regarded the future as entirely determined by the past, and therefore just as certain or closed as the past.  Determinism has been around long enough to be familiar to most educated people.  What is less well known is that many scientists have also questioned our understanding of the direction of time, as always going from what has been to what hasn’t yet been.  Some branches of science, such as cosmology and evolutionary biology, talk as if they believe in irreversible time, since they speak of some things having to exist before other things could come to exist.  Elementary particles had to come before atoms and molecules; bacteria had to come before more complex life forms; and so forth.  However, scientists working on a more fundamental level, such as relativity physicists, have suggested that irreversibility may be a matter of appearances rather than reality.  Perhaps time isn’t a movement toward new realities at all, but only the gradual appearance to some observer of what already exists.  Perhaps the future is just as objectively real as the past, although we are not yet subjectively aware of that future.

Now I’m going to try to give you some idea why a physicist might think this way, although I’m limited in two ways: (a)  I’m not well trained in this perspective, and (b) I don’t really find it very convincing!  To understand it I have to turn away from the kind of historical sociology that I’ve done most of my life, and focus on the elementary laws of physics, which are non-historical. Consider Newton’s laws of motion.  Suppose we have a series of observations of a body in motion, such as a ball rolling down an inclined plane.  The distinction between a certain past and an uncertain future does not, of course, appear in the observations themselves, since all our observations are of things that have already happened.  Nor does that distinction appear in the mathematical equations that physicists use to account for the observations.  We can calculate the acceleration of the ball by dividing the gravitational force by the mass of the ball, and that allows us to calculate with certainty the position of the ball at any point in time.

Equations like this are symmetrical with regard to time.  If we know the position of the ball at an earlier time, we can calculate what its position must be at a later time.  But if we know the position of the ball at a later time, we can calculate what its position must have been at an earlier time.  And once we have equations that account for the things we have observed, we can also use them to predict things that we haven’t yet observed. Nothing in the equation indicates that earlier events are certain but later events are uncertain.  On the contrary, science seeks both explanation and prediction, and so it tries to say both why the past had to happen as it did and what must happen under specified conditions in the future.  Classical physics describes a symmetrical world, in which the past and the future are in a certain sense one, all part of the same deterministic sequence.

Once we have gone that far, we may go all the way toward symmetry by saying that the past and the future actually coexist.  They are not only equally certain, but they are equally real.  Physicists have done this by thinking of time as a fourth dimension similar to the three dimensions of space.  They imagine a timeline, with events occurring at every point along the line.  All points on the timeline are equally real, just as all points in space are equally real.  This idea is sometimes called the “spatialization of time.”  As Einstein said, “It is a characteristic of thought in physics…that it endeavours in principle to make do with ‘space-like’ concepts alone.”  Einstein’s own theories of relativity strongly encouraged this kind of thinking.  One thing that space and time have in common is that both space and time intervals are affected by speed and gravity.  A foot has no absolute length and a second has no absolute duration.  As a result it can be 12:00 for one clock and 11:59 for another equally accurate clock, perhaps because they are running at different altitudes.  If it can be both 12:00 and 11:59 “at once” so to speak, then perhaps all times—and all temporal realities—coexist the same as different places do.  Whatever we see we call the present, but the past and the future exist somewhere in four-dimensional space.  That would also imply that time travel in either direction is theoretically possible. 

The problem is that this way of thinking is in serious conflict with our most fundamental commonsense beliefs.  We have no problem with the idea that different points on a spatial line are equally real.  But we experience different points on a timeline as existing only one at a time.  We experience the present moment as particularly real, and also as the dividing line between what has already come to be and what has not yet come to be.  And we ordinarily assume that what hasn’t yet come to be may or may not come to be.  How could we possibly regard a child that we might someday have as being just as real as a child we already have?  Those who have advocated the spatialization of time are forced to dismiss our most basic convictions about time as illusions.  Science has shattered our illusions before, perhaps most famously by denying that the sun revolves around the earth.  We still speak of the sun rising in the morning, but we now know that this is only what appears to happen, not what really happens.  Scientists who speak of the illusion of time are making a similar point, although a much more disturbing one.  They claim that process time is an illusion arising from a limitation of our perspective.  We are limited, at least for now, to moving along a timeline in one direction, seeing only one reality at a time.  But that doesn’t mean that what we are seeing is the only reality.  When we drive down a road, we see only one piece of road at a time, but we don’t deny that the rest of the road already exists.

Perhaps an even better analogy is a motion picture.  When we see a movie we have an illusion of life unfolding, but in reality the entire movie already exists as a set of frames on film.  When the frames go by very quickly, we get an illusion of motion, but if we could slow the movie down, we would see that each individual frame is without motion.  In theory, a timeline could consist of a series of infinitesimally small points or instants, each of which is a slice of reality.  All these slices of reality could coexist.  When we move down the timeline, we encounter them one by one, giving rise to an illusion of process.  But if we could slow things down enough to see a single instant, we would see that it has no motion, no change, no duration.  In the words of distinguished physicist Louis de Broglie:

In space-time, everything which for each of us constitutes the past, the present, and the future is given in block [a four-dimensional block of reality], and the entire collection of events, successive for us, which form the existence of a material particle is represented by a line, the world-line of the particle.  Each observer, as his time passes, discovers, so to speak, new slices of space-time which appear to him as successive aspects of the material world, though in reality the ensemble of events constituting space-time exist prior to his knowledge of them.

Herman Weyl puts it more simply: “The objective world simply is.  It does not happen.  Only to the gaze of my consciousness crawling upward along the lifeline of my body does a section of this world come to life as a fleeting image.”

That’s about the best I can do to explain a point of view that I don’t accept.  And I’m not alone.  Not all physicists agree on that interpretation of relativity theory.  As far as I know, they do agree that the length of time intervals can be different for different observers, and therefore different clock times can coexist.  But it doesn’t necessarily follow that the past, present and future coexist in any meaningful sense.  As I understand it, there is nothing in relativity physics to support the idea that you can observe your own future, or that any other observer can observe your future.[2]  We have no reason to believe that anyone can observe anything you do prior to your experience of doing it.  If the future is never actually observed, then no statement that the future already exists is scientifically testable.  We may then reasonably ask whether it is a scientific statement at all, even if it is put forth by scientists.

Philosophical support for process time

Beyond the scientific arguments, which can get rather technical, there is a fundamental question that some philosophers raise, namely whether this spatialized conception of time can contribute anything to a philosophy that we can live by.  Many philosophies take very seriously the concept of becoming.  The spatialization of time seems to eliminate the idea of becoming, at least in its most fundamental sense, which is coming to be.  If the future already exists, we can’t really say that it is coming to be; we can only say that we are coming to observe it by changing our position on a timeline.  Becoming can then have only two more limited meanings: For objects, it would mean merely coming to be observed.  And for human subjects, it would mean merely coming to observe, without actually altering that which is observed.  However, I think that gets us into a contradiction.  There is at least one thing that we must believe that we change in the course of our observations.  And that is ourselves.  New observations create new knowledge, and new knowledge changes us.  But if nature isn’t really changing, we can’t really be changing, since we are part of nature.  If process is an illusion, then our learning process must also be an illusion.  If the future already exists, then we must say that we already know what we haven’t yet found out.  But I know of no scientist who would take that position, because scientists believe in science itself as a process of acquiring new knowledge.  Process philosophers call this a “performative contradiction,” a contradiction in which scholars continue to affirm in practice what they try to deny in theory. 

One must be suspicious of scientific arguments that if taken to their logical conclusion would render all human activity meaningless, including science itself.  Without a meaningful concept of becoming, how can there be personal growth, intellectual development, or social progress, all of which scientists claim to believe in?  The existentialist philosopher Henri Bergson said, “Time is invention or it is nothing at all.  But of time-invention physics can take no account….Modern physics…rests altogether on a substitution of time-length for time-invention.”

Process philosophers like Bergson and Whitehead do not spatialize time, dividing it into infinitesimal instants like the frames of the movie, without motion or duration.  They only divide time processes into events, each of which requires some minimum amount of time to occur.  Their basic unit is not a still shot, but an event in which something is happening.  In Charles Hartshorne’s interpretation of process philosophy, each event is a “creative synthesis” which incorporates past realities into present reality.  There is a constant flow of the past into the present; the present contains elements of the past as its essential constituents.  For example, your past experiences with language are essential constituents of your present experience of making sense out of my words. You are constantly synthesizing what you just heard with what you previously knew in order to construct meaning.

From this perspective, time must have direction because each moment depends on previous moments, not vice versa.  And the future is uncertain because each event is a unique synthesis, a coming into being of something that has never existed before in its precise details.  A present event has only a general, abstract similarity to previous events, which permits a limited degree of predictability.  The next time you hear a word will be something like the last time you heard the same word.  But it won’t be exactly the same because something in the total context will have changed.  By focusing on concrete detail rather than abstract generality, process philosophers view every moment as unique and the future as open-ended.  Every moment is a creative moment. 

We may reasonably ask how we can make such statements, how we know these things to be true.  We do not know them from observation alone.  Strictly speaking, we can’t observe creative becoming, since everything we observe must already have come into being before we can observe it.  When we look at the stars, we don’t see them in the present but as they were many years ago, because it takes many years for their light to reach us.  But if you think about it, that’s true to some degree for all observation.  It takes time for the sound of my voice to reach you, or the light reflecting off me to reach you.  All observations are observations of the past.  You can notice differences among observations recorded at different times, but you cannot tell from the observations alone that anything truly creative has occurred.  The observations are just a pile of snapshots that could be glimpses of an unchanging block of space-time.  Your awareness of creativity doesn’t come from these snapshots, but from your inner experience of your own creativity, your unshakeable conviction that regardless of what you have done in previous moments, your next moment is open and offers you choices. 

Although we observe only the past through our senses, we actually live in the creative present.  We experience ourselves as being able to act in a number of different ways right now, under the same conditions, and thereby shape the future through our choices.  And unless we think we are God, we must assume that this creativity arises from a greater creativity beyond our own, either natural or supernatural.  The reason I say that is because we are talking about the nature of time, not just human nature.  I don’t believe that the emergence of our one species on our one planet could alter the nature of time.  If the future were already written, it would be written for everything, including humanity.  If we believe that our future is open, then we must also believe that the future is open in principle, and always has been, and that requires creativity on a cosmic scale.

A choice of perspectives

The debate over time presents us with a profound choice.  On the one hand, we can believe that the passage of time is only a passage between already existing realities, that the future is as real and as certain as the past, and that time is in principle symmetrical and reversible.  This view seems to reduce us to mere spectators of our own lives, watching a movie unfold without being able to alter a single frame.  On the other hand, we can believe that the passage of time is a passage from a closed past to an open future.  This view regards each moment of our lives as a creative moment that alters the future for better or for worse.

The philosopher Frederick Ferré sees this as a choice between mathematical abstraction and firsthand experience.  In Euclidean geometry, a line consists of an infinite number of points, each of which has no width.  If time is spatialized, a timeline consists of an infinite number of moments, each of which has no duration.  But a moment without duration is an abstraction that we cannot actually find in our experience.  Process philosophers say that it takes time to be, and so we can’t really separate being from duration and becoming.   Science relies on mathematical models to describe nature, and those models work for certain purposes, but if carried too far they oversimplify and distort reality.  The world of mathematical models is a useful place to visit, but you can’t entirely live there.  After discussing the spatialization of time and associating it with Einstein, Ferré says:

My mention of Einstein’s name in connection with this conception of time shows that it is a distinguished view.  Indeed, it has in recent years been virtually the only scientifically thinkable theory.  And yet it rules out, if it is accepted, fundamental human intuitions of the unfinished character of the future as contrasted with the settled character of the past and the decisive, event-actualizing character of the present.  On this view, there is no reality exposed by such intuitions….

It would not be too strong, perhaps, to say that this reversible, becomingless conception of time is the standard view of modern science.  We need not be surprised, therefore, at the sense of alienation that many have come to feel toward such science—many, that is, who are convinced of the importance of human intuitions into the decisiveness of the present and the openess of the future to various possibilities and into the objective nonreversisiblity of the present and the past.

This is what makes the work of certain physicists—like Prigogine, Bohm, and Stapp—so profoundly exciting and important.  They are challenging at its root an orthodoxy on how to conceive of time.[3]

Beyond science

The new physicists referred to by Ferré have been trying to develop new models of reality that are not only consistent with the scientific data, but also do justice to our fundamental intuitions about time.  The day may come when the attempt to minimize time will no longer have any serious support.  The fact that it did have so much support in the twentieth century may tell us something about the limitations of scientific thinking in that era. So I’d like to conclude with a brief comment on science and philosophy in general.  Whitehead was himself a scientist, but he didn’t believe that all truth could be found in science.  He said:

Science can find no individual enjoyment in nature: Science can find no aim in nature: Science can find no creativity in nature; it finds mere rules of succession.  These negations are true of natural science.  They are inherent in its methodology.  The reason for this blindness of physical science lies in the fact that such science only deals with half the evidence provided by human experience.[4] 

The half he’s referring to is the evidence given by observation of the outside world: extrospection as opposed to introspection.  Western thought in general, and science in particular, assumes that reality is to be understood by looking outward rather than looking inward.   Science takes a series of snapshots of things that already exist.  It then organizes the snapshots to find abstract patterns in them, and it regards those patterns as laws of nature.  From the standpoint of classical science, the principal characteristic of nature is its lawfulness, as if nature were nothing more than a grand machine performing the same routines over and over.  This approach to reality has been remarkably successful in rendering nature more predictable and controllable.  What it has not done is reveal the underlying creative process that generates the patterns themselves. 

Newton’s solution to this problem was to attribute all creativity to a supernatural God.  He regarded the laws of nature as God’s laws, which nature was simply bound to obey.  The sociologist in me suspects that this view was a reflection of the rigidly hierarchical and authoritarian social order of Newton’s time, in which order was imposed from the top down.  Modern science took God out of the picture, but retained the notion of a machinelike universe bound by rigid laws. 

I submit that this was an incomplete solution.  If we reject the concept of a supernatural God, then I think we have to acknowledge within nature some of the qualities previously associated with God.  There must be something in nature that is eternal, always having existed in some form, unless you believe that there ever was a time when there was sheer nothing, and something somehow emerged out of nothing, which would be the mother of all miracles.  It is nature that must be self-sustaining, self-generating, self-organizing, self-modifying—or in a word—creative.  Time must lie at the very heart of that creativity.  But it must be process time, irreversible, open-ended, constantly synthesizing something new from what has gone before.  The creativity we find within ourselves—our own “spirit” or “soul” if you like—is our best evidence that this kind of time exists.  And it must have existed long before us, since it was surely beyond the power of the first humans to invent it.  This is part of the great mystery that lies beyond scientific understanding, at least the kind of scientific understanding that has prevailed to this day.  No wonder science has tried to evade the issue by minimizing the importance of time.

Some scholars make a distinction between science and scientism.  Science is a wonderful method of inquiry based on empirical observation and logical reasoning.  Scientism is a futile attempt to turn science into a complete philosophy of life.  I like to put it even more bluntly: Scientism takes good science and turns it into bad philosophy.  It does this by assuming that the aspects of reality most accessible to empirical observation are the only realities.  The result is often a deification of science and a disparagement of all other ways of seeing, whether religious, philosophical or artistic.  The tension between science and other perspectives can be a healthy tension, but it can also be a mutually destructive antagonism.  Our Unitarian-Universalist distaste for war ought to extend to such intellectual wars, and our commitment to respecting diversity ought to include respect for all the ways we can know ourselves and our universe.

Closing words:

“It is impossible to meditate on time and the mystery of the creative process of nature without an overwhelming emotion at the limitations of human intelligence.”

--Alfred North Whitehead

References