A Brief Explanation of Time
The Need for Time
Time, goes the old joke, is nature’s way of making sure that everything doesn’t happen at once. Like many jokes, this one has a fairly large grain of truth. If two states of the same object are allowed by the universe, such as being red and being green, or being in one place and being in another–or if two objects, such as two fundamental particles of the same mass, spin, and charge, can occupy exactly the same state and place–then major problems arise. Either, in the first case, the principle of identity is violated–is it one object or two?–or, in the second case, there is not room in space for both objects at once (in physics, this problem is known as the Pauli exclusion principle). In a universe of pure space, without time, the laws of science could not exist because identity and location could not be reliably established.
Time gives the universe a way of connecting different states of the same object (first it was red, then it turned green; first it was in one place, then it was in another) and of spacing out events and objects so that they do not get in each other’s way (first one atom was there, then another). Further, if one of the states of an object has to exist if the other is to exist, time provides an order of events. The tree cannot exist unless its seedling has earlier existed, nor the seedling without the seed; whereas the seedling could exist without the tree but not without the seed. Time is whatever space a logical scheduling problem requires for its solution.
We can actually study situations where time almost doesn’t exist. In the tiny and always minutely brief world of quantum mechanics there is so little time that identity and location do indeed lose a good deal of their clarity and indeed their distinction from one another: a particle can exist in a state of superposition, in which two different things are true of the same object, and it can exist very tenuously in two places at once. But for objects with more solidity and persistence, time is necessary not just tautologically for them to exist “in” but also as a way of resolving paradoxes of being and location. Another place where time almost doesn’t exist is in black holes, where it is only their slow leakage and eventual unlocking that prevents paradoxes such as that information can be destroyed (a contradiction of identity) and that two things can be in the same place (black holes can be almost infinitely dense with matter).
The Enlightenment description of time, which is familiar to us all–and which even after ninety years has not been replaced in our intuitive imagination by relativity theory, let alone other modifications of it–sounds like the simplest way of providing the “spacing-out” and scheduling function that is so important to the universe. What it says is that time is very like a spatial dimension–say, length–extending out in a straight line, and that everything in the universe at any given moment is at the same point on that line; what is on one side of us is the past, what is on the other is the future, and where we all are is the present.
But wait: all is not well here. When it comes to the “passing” of time, the familiar model begins to get complicated. The present moment moves along the line in a futureward direction providing each point in it with an infinitesimal moment of reality–or, in the opinion of some physicists and philosophers, the whole line is always already real, and our consciousness moves along the line, like a spotlight, giving us the illusion of encountering a new future and leaving behind a dead past. But the space analogy has already begun to break down. Our experience of space doesn’t necessary include a “passing of space”; there’s no necessary point of maximal existence along a line, or maximal human attention to it, and there’s no place on a line that all of the universe is at. And if either reality or our awareness moves along the line, in what time is it moving? How fast? How many miles per what? Can it accelerate? how could we tell the difference between slow and fast? and if we can’t, how could we tell if it had or hadn’t stopped altogether? what does “move” mean if there’s no discernible distinction? Is there a second time in which reality or awareness moves along the line of the first time? Then why not a third time in which the reality of the reality or the awareness of the awareness moves along the second? And so on.
If the whole timeline is already there, moreover, then the future is merely awaiting its actualization or our attention to it, and cannot be changed. So we are bound to the rails of fate and such fundamental values as morality, freedom, responsibility and creativity are illusions. This reflection might be bearable for a philosopher who preferred truth to moralistic wishful thinking, if it did not also imply that the philosopher’s own cogitations are part of the same clockwork, and the feeling that something must be logically true is too, so truth is also an illusion. And there is no way of checking whether such an automaton is correctly calibrated, so as to verify that the illusion of truth coincides with its reality.
Equally problematic is the direction of time. Space doesn’t have a preferred direction. In space one can get from London to Paris and from Paris to London, but whereas one can get from A. D. 1980 to A. D. 2001 in time, one can’t, as one could with space, get a return ticket. Nineteenth century thermodynamics showed that thermal and energetic events in the universe always went one way–toward the increase of entropy. You can burn a log but not unburn it, you can let perfume diffuse out of an open bottle but not suck it back in again, you can turn work into heat and heat into work but only if you pay a tax or interest of work energy on the exchange each time. But then the study of biological metabolism and evolution seemed to show that living systems can feed upon the flow of the increase of entropy, like paddle-wheels in a torrent. Without violating the Second Law of thermodynamics, a tree can turn ash (soil) and smoke (atmospheric CO2) and heat (sunlight) back into a log, and a rose can suck chemicals out of air and soil and make perfume. So not only can time possess at least two directions, different kinds of organisms can take different directions.
In the twentieth century, relativity theory showed that the universe is not all at the same point in the line; a present moment is not something simply given to the universe, but rather something rather fuzzily earned by two-way communication among objects and events that puts them in synch with one another. An “in-synch” region is called an inertial frame. Some parts of the universe are in different inertial frames from others and our present knowledge of them is necessarily of their past, while other parts of the universe are over our event horizon and we can never know them. And if we cannot know them, the proposition that they exist and share our present moment is a purely metaphysical and unscientific notion–unless we improve our model of time.
More recently still, quantum theory showed that the state of knowledge that exists about a particle partly determines its nature and identity–disturbing enough, but more so if we reflect that one can only know about something after it has happened, since even the fastest messenger, light, has a finite speed. This means that knowledge must somehow retroactively affect what it is knowledge of; so the present-point on the line can be neither the spotlight of awareness (we are aware only of past events), nor the place where reality momentarily condenses (since it is busily condensing previous realities).
So the Enlightenment time-line description ends up by being not so simple after all, and worse still, it is full of contradictions. It was contradictions, after all, that we needed time in order to resolve, and if our account of time just introduces more of them, we are worse off than we were before. (If it strikes the reader that I am sliding back and forth between the universe’s need for ordered time in order to exist coherently, and our need for ordered time to explain the universe with, that slide is entirely intentional: for after all we are part of the universe, and any problem of ours is thus a problem of the universe’s as well. This little move or slide is going to be important later on.)
Evidently no simple description of time will do. It looks as if we may have to settle for a description that is at least not contradictory, and let the complications fall as they may. Certainly we will have to abandon the timeline concept; which means that we will have to be very skeptical about clocks (analog ones which wind the timeline onto a dial, or digital ones which map it onto the line of natural numbers) and calendars (which winch it onto the larger pawls of months and years).
An Emerging Solution
A new view of time is emerging from a variety of disciplines. However, this new conception is as yet fragmentary, divided among schools and disciplines often at odds with each other. I shall here treat it as a unity rather than as a collection of competing hypotheses, because I am convinced that in this case to demand the kind of elegance we expect of a scientific theory, that complex details and phenomena can be reduced to a single simple principle, would be a mistake. If time is, as I will argue, precisely the principle of complexification, we should expect any true theory of it to be a messy Rube Goldberg contraption rather than a graceful piece of abstract geometry.
We can summarize the new time-conception under six propositions:
1. Time is complex and concentric.
2. Time is generated by objects and organisms and its local properties vary accordingly.
3. Time is evolving and emergent.
4. Time is branchy and thus free.
5. Time is looped and nonlinear.
6. Time is self-pruning and thus providential.
Complex and Concentric
Like Chinese boxes or Russian dolls, time is a nested hierarchy of temporalities. This idea has been ably synthesized by the International Society for the Study of Time and its founder, J. T. Fraser. Human time contains the more primitive times of animals and of living organisms in general, which in turn contain the time of matter with its electrochemical and crystalline clocks; and matter-time contains the cruder time of quantum particles and light, out of which all things are made. When brain scientists began to investigate human consciousness, the experience of the self as a simple and single being was revealed as an illusion, one marvellously constructed, to be sure, by the nervous system so as to establish unitary command, but actually composed of a huge range of neural mechanisms. Likewise our experience of time as a simple flow is a fine neural achievement, a sort of Michael Jordan arabesque that looks so easy from the viewer’s end.
Generated by Organisms
Time is not a medium or container within which things happen: it is a property generated by the things themselves, individually and together. J. T. Fraser coined the term “temporal umwelt” to describe this idea. The animal ethologist Jacob von Üxkull used the word “umwelt” to mean the world as it appears to a given animal and as an animal can affect it, according to what senses and limbs it possesses. A blind mole has an umwelt that involves digging but not seeing: a hawk one that involves seeing but not digging. Atoms are sensitive to the four forces of physics but to nothing else and cannot, for instance, respond to a goose’s mating dance or stalk prey or be offended by a slight or even individually exert gas pressure. Humans can extend their umwelt by machines like airplanes and bulldozers and instruments such as telescopes, radios and oscillographs. The temporal umwelt of an organism is whatever kind of time it needs to experience things and to do things. Our complicated human sense of time includes its present moment, its continuity, its before and after, its past and future, its futureward direction, its memories and prophecies, its anticipation of death, and its conscious freedom, illustrated by its branched verb tenses (as in such sentences as: “If you had invested in Microsoft you could have retired three years ago and would be able now to choose whether to live in France or Hawaii”, which implies several branchpoints of decision and alternative timelines).
But human temporality is only the outermost shell of a series of simpler temporalities. Next down is biotemporality, the time of non-human life, which lacks much of the higher machinery but retains a direction, continuity, a present moment, and a past. Next down (or in) we find the temporal umwelt of molecular matter, which possesses continuity and a direction (given by the increase of entropy) but no present moment, past, or future. Deeper still is the temporal umwelt of atoms, which possesses continuity but no necessary direction–no earlier and later. You can run the movie of atoms moving about and bouncing off each other forwards or backwards without a discernible difference or violation of scientific laws, whereas if you did the same thing with an energetic chemical reaction or the diffusion of a gas (or a vase falling and breaking) there would be clear absurdities. Simpler still are quantum particles, which don’t even possess temporal continuity: each occupies its own little fragmentary and eternal spot of time. We humans are made up of all these levels and can experience the lower ones in our feelings of animal lust, roller coaster rides, mystical trance, dream, sleep, and death.
Different organisms at the same hierarchical level also differ in their temporal experiences and capabilities, but in ways that are more easily translatable into each other than across levels; animals of different species can understand much of each other’s behavior, but atoms cannot understand animals. Human science is the art of such translation.
Evolving and Emergent
If time can be hierarchically nested, and its nature contingent upon the local system where it is studied, a further implication follows. Time itself evolves. As we have noted, time is that which enables the universe to sort and space out different states of a system so that they do not coexist in a paradoxical violation of identity. Time enables a tree to be a seed, a seedling, and a mature tree in order rather than all three at once; and it gives the rule for what order those states should take. The order in which temporalities are nested is also the order in which they appeared; the more complex and elaborated following the less complex and rudimentary. Higher more complex temporalities evolve out of lower simpler ones. And this principle is robustly proved when we look at the order in which the objects and systems that comprise the universe made their evolutionary appearance. In the big bang, only elementary particles existed, with their rudimentary temporality. Soon afterward, when the universe cooled enough for them to exist, atoms appeared, with their characteristic of temporal continuity. Molecular matter followed, with its characteristic tendency to become more thermally disordered over time. Then life, with its present moment, its genetic or neural memory, and its ability to make order out of entropy. Finally, humans, and their panoply of tenses and their awareness of freedom and death.
There are several measures by which we can guage this evolutionary process, some simple, others less so. For instance, the universe begins very hot and at very high pressure; naturally it expands and so do the systems that make it up. As it gets bigger, its density decreases, like an exploding gas or liquid; and first-year thermodynamics tells us that an expanding gas or liquid must cool. As the universe cools, new forms of order crystallize out, like frost-flowers forming on a windowpane–first gravity, then the strong and weak nuclear forces, then electromagnetism, then coherent matter, then crystals, then living organisms, and finally ourselves. Each new form of order differs from its predecessor by being more reflexive, self-referential, self-maintaining, and self-replicating: a wave of energy merely reproduces itself as it flees its point of origin at the speed of light; matter is energy that uses part of itself to bind itself into a stable knot that can occupy a single location; life is matter that contains a replicable DNA record of itself; human culture is life that knows itself neurally and can breed itself into new forms. This increased reflexivity is identical to an increase in temporal complexity: the more conscious and self-referential and self-ordering a system is, the higher its temporal umwelt.
The mechanism by which this series of emergences occurs is becoming familiar to chaos theorists: it is self-organization in complex far-from-equilibrium situations, crises sometimes known as bifurcation points. An ordered system spontaneously appears as one of a number of ways in which a stressed (in technical terms, a damped, driven) environment solves its energy-budget problems; this process in isomorphically similar to the emergence of equilibrium solutions in the context of both zero-sum and nonzero-sum games. You can observe this happening when a pan of heated water adopts a rolling boil, thus solving the problem of how to transfer heat from the bottom of the pan to the air. A hurricane is a larger version of the same thing, and the Great Red Spot on Jupiter a larger one still. The frost-flowers, and crystallization in general, provide another example, with the stress this time provided by cooling rather than heating. The bodies of mature animals and plants are the unimaginably complex emergent answer to the problem of how to find the most parsimonious solution to the turbulent interaction of all the proteins their embryonic DNA has specified.
Branchy and Free
In a range of scientific disciplines, branchiness has become a dominant theme in explaining how the world works. Most quantum physicists accept some version of Hugh Everett III’s idea that in the absence of any mechanism of choice, every time a quantum event occurs in which there are equal probabilities of different outcomes, each of those outcomes does indeed happen, initiating at the branchpoint a new parallel universe, a new timeline. Since quantum events are happening all the time everywhere, this would produce a rather unruly foliage of temporal dendrification–but there are pruning shears available in nature, which we will look at in a moment. Branchiness is a key concept in many other fields. Evolutionary theory concerns itself with the branched lineages of life. Anthropological studies of kinship and descent, scholarly establishment of influence, provenance, or text, electrochemical investigations of alternate molecular pathways, all accept a branchy view of the world. Computer science is all about branches–a transistor is a controllable branchpoint. Logic itself is the study of branchpoints such as ands, ors, ifs, boths, and alls.
The branchiness of things as we now conceive them stands in marked contrast to the iron rails of unique linear deterministic cause and effect as conceptualized by the eighteenth, nineteenth, and much of the twentieth centuries. There is not one line of necessity. The universe is now increasingly coming to be seen as an open system, with freedom as a constitutive principle. Though we can still see the causes by which some situation came to exist, we are also aware of other plausible outcomes, and we know that some situations are hugely and irreducibly unpredictable, and that all events are unpredictable at some minute level of exactness. Humans are no longer seen as unique in being free–everything is, more or less; our uniqueness is now that we recognize and can to some extent control that freedom–even, as we bind ourselves with promises, freely corral our own freedom and prune our possible futures.
Looped and Nonlinear
As we have already noted, quantum theory makes the observer a player in reality, and observation always takes place after the fact. Thus the future of an event can help determine that event, so that now a weak “backward-in-time” influence is added to the strong “forward-in-time” constraints of causality, thus closing a feedback loop and rendering time nonlinear or looped. We are now observing the big bang in the form of radiation that set out thirteen billion years ago, and thus in some very minute way we are helping determine how the big bang happened. The physicist John Archibald Wheeler has argued that since events require observers to transform them from mere probabilities into actual realities, the only real big bang that could occur would be one which would later bring about observers of it. This is not as radical an idea as its initial formulation as the Anthropic Principle would suggest; even atoms are reasonable candidates for being observers in the physical sense, and harmonics among quantum waves can bring about a similar collapse from distributed probability to coherent near-certainty. Nevertheless, how something is observed affects its nature, as well as simply that it is observed; and humans can observe in a variety of new ways, asking new questions of the universe to which the universe–including its own past–must suddenly come up with an answer, never having had the need to “make up its mind” on the issue before.
The more exciting implication of this nonlinearity of time is that observing beings in our own future, or futures, must one day be observing us, and thus rendering what is indeterminate about us definite and real. If we are faintly aware of this process going on, that awareness would nicely correspond to such claims as prophetic inspiration, conversations with angels or spirits, the voice of conscience, near-death experiences, divination, deja vu and other phenomena.
Self-pruning and Providential
If we combine the ideas of branchiness and loopedness, an extremely interesting possibility emerges.
Though physicists accept the parallel universes theory, they do so grudgingly; there is something deeply cumbersome about all that foliage of timelines, and the problem remains of where they all are–why can’t we see them? The only space for them is, after all, space–the same space that we occupy. Why doesn’t their combined near-infinite mass crush our universe in an instant? If they are separate from us in space, how did they get there? If a whole new universe branches off from some quantum event in my fingernail, where does the energy come from to transport it trillions of light years away so that it doesn’t get in the way of this one? The universe does contain a lot of “dark matter” that we can only detect by the influence of its mass, but it is only a small multiple of the ordinary matter we know and love; there is room in that mass for some alternative futures of past events, but not many. Again, the universe does have a quantum fuzziness at small scales, such that quantum superposition and nonlocality can flourish; we can interpret that fuzz as the penumbra of parallel universes hovering around this one; but at larger scales that fuzziness is damped out.
How, to return to our former puzzle, can the foliage be pruned? If the universe is free, how can that freedom be transformed from arbitrary randomness to definite choice? The retroactive observer-participant effect gives us a neat answer. The futures prune the past. Later states of the universe, containing, we hope, more and more intelligent and beneficent observers, are helping us–and helped our predecessors in the living and chemical and physical worlds–to choose one future out of the many on offer. The future is still not determined, that is, there are several possible futures, each with a probability of less than one; depending on the level of their probability and their coherence with other futures, they can weakly affect us by observing us, but only with our cooperation, and we can abolish them or render them more likely by what we do. We thus live in a deeply moral universe, where good and evil futures whisper their suggestions to us in the quantum fluctuations of our synaptic junctions, and we must choose by our actions the best futures we can.
The correspondence of this idea with the teachings of all human religions should be clear. There is a (somewhat beleaguered) providence that can offer us grace or enlightenment if we choose to accept it, our moral actions are important, and we are in relationship with beings that we have always strangely represented as like children–putti, cherubs, the fat infantile Buddha, the Christ child–as he called himself, the “son of Man”, elves, spirits, alien abductors, and so on–because they are indeed our descendants. And if, after billions of years, those beings all agree on their story and achieve a transcendent unity, then the universe will have been all along the fetus of a gestating God, among whose infant neurons, gradually wiring up the synaptic connections, we can count ourselves.
The reader will recognize that these last sentences are clearly speculative and poetic. But the model of time we have possessed for over two hundred years will clearly not hold up any more. The relationship between the past and the future can no longer be seen as like a line, but more like a solid at least, a sort of expanding sphere whose innards are the past, whose surface is the present, and whose outside is all the possible futures. Past is to future as part is to whole; our ignorance of the future is the ignorance of the individual brain cell about the huge and mysterious thoughts that it mediates and in whose formulation it participates. As the physicist Arthur Eddington put it, the universe is not so much like a vast machine as like a vast thought. And Time is the milieu of that thought.