Time is of the essence. It flies, stalls, and like other things, runs out. But what exactly is it? Thinking about the existence and nature of time, one’s mind often wanders towards science fiction’s fantasy of time travel. But what exactly is the TARDIS travelling through? What precisely is it that we measure with our clocks?
The answer to this most existential of questions has occupied, ravaged and been disputed by some of the greatest minds in both Physics and Philosophy. This paper attempts to explore some of the concepts posited by both physicists and philosophers, from Plato to Einstein, observing the unique similarities and differences between each of them.
2. RELATIVELY ABSOLUTE TIME
The Newtonian concept of time was one of absolute certainty.
Absolute, true, and mathematical time, of itself, and from its own nature, flows equably without relation to anything external (6-12).
Time was constantly moving forward at the same rate, unaffected by our actions. Newton believed that the nature of time was independent of our existence; time has and will always exist. These views, however, with Maxwell’s observations and Einstein’s revolutionary theory of relativity, were soon to be highly challenged and later, disproved. Before Danish astronomer Ole Christensen Roemer’s discoveries, it was believed that the speed of light was instantaneous. Observing the eclipses of the moons of Jupiter in 1676, Roemer was able to conclude that light had a very high but finite speed, which we now know today to be 3×108 m/s. This theory was further exemplified in 1865 by British physicist James Clerk Maxwell. Maxwell deduced mathematically that both electric and magnetic forces are found in the same field, thus showing that electricity and magnetism were two inseparable entities, giving rise to the electromagnetic force that we know today. Maxwell also predicted that there were ‘wavelike disturbances’ in the electromagnetic field and upon calculation found that the speed of these waves coincided with that of visible light. Maxwell’s theory thus implied that light waves travel at a fixed speed -a concept that diverged from Newton’s theory of the fictitious absolute standard of rest.
Reichenbach argues that there is no way of actually measuring the velocity of light and proving that it is a constant. He states that this proof is dependent on the definition of the characteristics of simultaneity, which is in turn dependent on the speed of light, reaching to the conclusion that the proof itself is dependent on the outcome. Therefore, Reichenbach suggests that neither Einstein nor Maxwell proved that the speed of light is constant, but assumes it is, by definition, one.
Thus Newton’s theory created another dilemma — if there is no universal agreement on the standard of rest, then how can there be a universal agreement on the speed of an object? To explain this, we must use Hawking’s analogy of the ping pong ball.
If one carried out experiments with moving bodies on the train, all Newton’s laws would still hold. For instance, playing Ping-Pong on the train, one would find that the ball obeyed Newton’s laws just like a ball on a table by the track. So there is no way to tell whether it is the train or the earth that is moving (20).
If you were playing ping pong on a train (moving at 100 kilometres per hour), you would expect your opponent to measure the speed of the ball at roughly 50 kilometres per hour. An observer on the platform, however, would see the ball travelling at a much higher speed, combining both the speed of the ball in the train along with the speed of the actual train itself and so would measure the speed of the ball at roughly 150 kilometres per hour. Thus the speed of the ball is relative to both the player and the observer on the platform, and from their respective perspectives they are both equally correct on the speed of the ping pong ball.
Should the speed of the ball be measured relative to the platform or to the train?
Verse 9 of the ‘Gola Pad’ in the Aryabhattiya, written by Aryabhatt in the fifth century, also mentions a similar ‘thought experiment’ showing that perhaps he had conceived the notions of relativity and space-time centuries before Einstein stumbled across it. Verse 9 states:
As a man in a boat going forward sees a stationary object moving backward just so at Lanka a man sees the stationary asterisms moving backward (westward) in a straight line (64-66).
Here Aryabhatt is clearly describing the effects of relativity; the scenery surrounding a moving boat seems stationary from the perspective of a spectator on a river bank, but seems to be moving backwards from the perspective of the passenger. We can see that relativity is not a modern concept, but dates back thousands of years.
So what are the implications of Maxwell’s theory and what has this got to do with time? Take the equation speed = distance/time. It was originally believed that time was the constant in this equation when concerning light, that at the same time if one were to observe for example the light rays of the sun at different points on the earth, as the distance varies, the speed too must vary. Maxwell, however, proved that the speed of light is constant, and therefore it is both time along with distance that varies.
Length and duration have to become flexible… [I]n Einstein’s relativity all time became local time and all space became local space (134).
In 1907, Albert Einstein famously proposed the concept of space-time. Space and time were not two distinct variables, but intrinsically linked and dependent on each other in the field of space-time, much like the forces of electricity and magnetism. The flexibility of time and space can easily be explained in the notable ‘twin paradox’. Imagine a pair of twins born at the same time, who are then separated at birth. One is kept on Earth while the other is put on a rocket to a star thirty light years away with a speed 99.9 percent the speed of light. For the twin on earth, sixty years pass until her sister returns, however, only three years pass on the rocket. While the sister on earth measures a distance of thirty light years between her and her sister, the sister in the rocket would measure only 1.8 light years. ‘The twins do not share the same time and they do not share the same space.’
The important thing to interpret from this thought experiment is that both twins are right according to their respective perspectives; they both have made accurate measurements. It is this that is Einstein’s fundamental principle regarding time — there is no ‘right answer’, as there is no absolute conception of ‘now’ in absolute time and space. Einstein turned the whole concept of time on its head. The implications of his theory of having no absolute frame of reference changed the way physicists looked at the world, forcing them to renounce their Newtonian beliefs. If there was no concept of ‘now’, then the actions you perform tomorrow, and the days after that, already exist. The future becomes predetermined.
3. THE IMMEASURABLE CONTAINER
In Book XI of his Confessions, Saint Augustine famously exclaims:
What then is time? If no one asks me, I know; if I wish to explain it to one that asketh, I know not: yet I say boldly that I know.
The question has puzzled generations of philosophers from Aristotle to Leibniz. It is an inexplicable concept into which the deeper we delve, the less we seem to know. Aristotle argues that time does not exist independently to the events that exist within it, that time in its essence is defined by the relativism of temporal actions. It can therefore be assumed that concepts such as the unanimous ‘freezing’ of events while time passes cannot exist as time in itself occurs due to the change of events. Arguing epistemologically, since we have no record of such freezes, one must assume that they have not and cannot occur.
Others, such as Plato, Newton and Leibniz, however, believe time to be ‘like an empty container into which things and events may be placed’; independent to the events that occur within it, and therefore ‘time freezes’ can occur. Platonism suggests that there are objects that exist neither in space or time. Take for example the number 7. It is non-physical and exists independently to space, time and our thoughts (i.e. it is not just an idea in our heads), and thus a Platonist here would argue that the number seven is an abstract object, but an object nevertheless. Numbers are objects that exist, but not in space or time. This further accentuates his argument that time itself is independent to events, if objects too can exist independent to time.
Saint Augustine poses the question, ‘In what space then do we measure time passing?’ Focusing on the concepts of the past, present and future, he presents his case, — that due to the fact that time flies with such speed from the future to the past, there is no space for the present. He goes on to say that we thus cannot measure time, for the past does not spatially exist, as the events have already occurred, and neither does the future, as the events are yet to come. As we cannot measure something that does not exist, we surely cannot measure time. Saint Augustine begins to break down the boundaries that govern what constitutes as past, present and even future.
Einstein too advocated the discontinuity of the past, present and future. Due to relativity (going back to the twin paradox) one person’s future will already be another person’s past if we observe them from an objective point of view, as both twins are travelling at different speeds (one in the rocket and one on Earth). Thus there is no objective past, present or future, but they are all overlapping relative to one’s perspective. He once famously said, ‘People like us, who believe in physics, know that the distinction between past, present, and future is only a stubbornly persistent illusion.’ It can thus be argued that there is no reason for such concepts, if they have been proved to be merely figments of our imagination.
Actions once completed belong to the realm of the past, but ‘I behold it in the present, because it is still in my memory’. The action therefore exists in both the past and the present. An action that is yet to occur belongs to the realm of the future, but by thinking about said action, it now also exists in the present as well as the future. Thus, Saint Augustine breaks down the borders of temporal action, seemingly agreeing with the Platonist view of time, that it is an unchanging immeasurable container in which events may occur.
4. THE DOUBLE HEADED ARROW
Leonard Boltzmann, through his equation, S = k. log W, explained the second law of Thermodynamics using entropy. The second law of Thermodynamics suggests that in a cyclical process, the entropy will increase or remain the same. Thus entropy gives us information about the evolution of a system over time. Boltzmann suggests that things usually start with a low entropy and move towards a state of high entropy, as the probability of them achieving this state increases with time.
This concept is supported by the observation of the ‘expanding universe’. Cosmologists have observed the universe expanding at an increasing rate, at around 67 kilometres per second, through which entropy can suggest that the universe originated as a highly dense and smoothly ordered system. Since entropy teaches us about the nature of a given system over time, it gives us the direction of ‘time’s arrow’. ‘If snapshots of a system at two different times shows one state which is more disordered, then it could be implied that this state came later in time.’ This theory implies that time is infinite, carrying on forever, as we ascend into higher and higher entropy.
The arrow of time, however, does not incorporate for the concept of past and future.
Although the equation fits both ways, in order to make sense of things and for the equations to directly link to our experiences, cosmologists have unanimously decided to make the arrow of time point towards our concept of the future.
The further and further into the past we go the degree of order increases until we get to a single point, the “singularity”, speculated as the Big Bang, a dense area of space-time, the most highly ordered concept in the universe to have ever existed, from which time originated.
5. THE ENTANGLED CUP OF CORRELATIONS
The phenomena of quantum entanglement (‘Spooky action at a distance’, as Einstein called it) gave rise to quantum mechanics and modern computer science, and Dr Seth Lloyd, Professor at MIT, believes it may just solve the aforementioned crisis of ‘time’s arrow’. The theory of quantum entanglement states that a particle, untouched, is in a ‘pure state’. When two particles interact, however, their states change, and they ‘become entangled components of a more complicated probability distribution that describes both particles together’. The state of the two particles remain forever entangled, and they could travel light years apart, but their spin would always remain correlated. It is this correlation that Dr Lloyd uses to help explain the arrow of time.
Take a cup of coffee, for example. As time increases, the coffee particles and the surrounding air particles interact and their correlation increases until eventually they reach an equilibrium and the coffee cools to room temperature. Lloyd spent years observing the entanglement of particles, and their correlation in binary form – a ‘1’ for anti-clockwise spin and a ‘0’ for clockwise spin, for example – and discovered that these particles, as they interacted, began to lose their own particular identities, and became pieces in the giant quantum correlation jigsaw, where eventually their correlations hold all their information and the individual particles hold none. It was at this point that the states of the particles stopped changing and the coffee drops to room temperature. ‘Lloyd realised “The arrow of time is an arrow of increasing correlations.”’
Boltzmann and the giants of 19th century thermodynamics believed the arrow of time followed the increase in entropy. Sandu Popescu and Lloyd, however, along with many other physicists, now believe that although at a closer perspective the entropy of the universe is evolving, as a whole the universe remains at an equilibrium. It is instead quantum probability that drives the arrow of time. While the laws of thermodynamics could be interpreted to show that the cup of coffee can theoretically start to warm up by itself (as there is no fixed direction of time), it is quantum entanglement that shows that the statistics of achieving this are near impossible. As things begin to correlate we know that time is moving in that direction, and as particles can never untangle, we know that time itself cannot reverse.
Philosophically speaking, quantum entanglement can explain the concept of the present, the elusive ‘now’, and explain why we only seem to remember the past and not the future. Our ability to remember only the past is another confounding manifestation of time’s arrow and can be seen as a build-up of correlation of particles. As you read something off a piece of paper, the photons become correlated with your brain as they reach your eyes and you remember it. It is from this moment, from the initial correlation, where your memory begins. As Lloyd put it, ‘The present can be defined by the process of becoming correlated with our surroundings.’
Although it helps to define the arrow of time, and give a clear view of what the present is, quantum entanglement has yet much to explain. While it gives time a direction through probability, it has no say in concepts such as the Big Bang or even the Big Crunch, or why we perceive time to be continually flowing. As Popescu puts it, despite his years of research in this field, time is ‘one of the greatest unknowns in physics’.
6. TIME IN THE ETERNAL TRUTHS
Many of the philosophies originating in India touch upon the concept of time, a factor that affects the metaphysics of all other entities. The ubiquity of the temporal dimension of human experience can be expressed in the phrase:
Na so’sti pratyayo loke yatra kālo na bhāsate │
There is no cognition in the world where time is not manifest.
Upon diligent examination of the Vedas (known also as ‘the eternal truths’), it can be seen that Indian philosophies hold a ‘spectrum of views about time’ (39-48). There are six major orthodox schools of philosophy – Nyaya, Vaisheshika, Samkhya, Yoga, Mimamsa and Vedanta – and four major heterodox schools, i.e. Jain, Buddhist, Ajivika and Charavaka. A study of the notion of time in Indian philosophy is of particular interest in association with the Nyaya-Vaisheshika schools, whose metaphysics and doctrines of creation and causality heavily rely on the theory of mahakala, or absolute time. They associate eight definitive characteristics with the concept of time. ‘For the Nyaya-Vaisesika philosophers, time is all-pervasive (vibhu). It is an eternal category of existence (nitya padartha); that is to say, it is without beginning (anadi) and without end (ananta), it is uncomposite (niramsa), does not presuppose any substratum (anasrita), it is an independent real (svatantra) and unchanging (niskriya).’ Here time is described as an entity itself. Unlike Boltzmann’s view of an arrow of time forever moving forward, the Nyaya-Vaisheshika schools perceive time to be static and above all actions that occur within it, more inclined towards the Platonist view and Einstein’s theory of space-time.
For the Samkhya-Yoga schools, ‘time, as a category of existence, does not figure in their list of tattva’. Time in Samkhya is implicit and indirect; one must simply assume that it exists, underlying all actions, as the matter is not explicitly addressed. The Yoga school, on the other hand, propounded:
Sa khalvayam vastusunyo buddhi nirmanah sabdajnananupati.
That the idea of a unitary objective time either as a collection of moments or as an objective series is a subjective representation, devoid of reality (39-48).
Much like Einstein’s space-time, Yoga explains time to be a collection of moments, an infinite number of ‘nows’.
The non-dualistic structure of Advaita Vedanta explains the concept of reality as ekamevadvitiyam – the-one-without-a-second. It refutes the Nyaya-Vaisheshika concept of the reality of time, believing time itself to be an illusion. Reinforced by the negative phrase neti neti (not this, not this), Advaita Vedanta defines the ultimate reality (Brahman) to be untainted by time.
The Jain philosophical approach to time is an atomic one. This philosophy, believing firmly in the reality of time, perceives it to be in the form of time atoms (kalanu) that are not only real and objective, but like the Nyaya-Vaisheshika view, are also anadi and anant, without beginning or end. The atoms of space and the atoms of time are believed to be distinguishable, as although particles of space (i.e. matter) can coalesce to form larger particles, particles of time remain singular and cannot combine to form some sort of hybrid time.
The more intriguing take on time by Indian philosophies is that of cyclical time. While Judeo-Christian views are that of linear time, Greco-Indian traditions take a more cyclical approach. As implied by the concept of a circle, a future event also becomes a past event and a past event also becomes a future event, thus destroying the whole concept of distinct factions between the past, present and future. Some may argue that this view of looking at time makes history meaningless, that the actions that have occurred will eventually repeat themselves again and there is therefore nothing special about the deeds committed in the ‘past’. The Greek concept of cyclical time is interpreted through ‘Eniautos’ (Great Year) which occurs when the cosmos completes one cycle. The Indian approaches to this are slightly different but they too all commonly hold their roots in cosmic cycles. For example, it is stated in the Vayu Puran that a ‘world cycle’ is a day of Brahma, and the cosmic dissolution (pralay) is his night. The world cycle is then divided into smaller units ranging from manvantaras to mahayugas to yugas. There are believed to be four yugas that continuously repeat themselves. These are: Satyuga, Dwaparyuga, Tretayuga and Kaliyuga. Each world cycle is said to last millions of human years. It is said that one lav of Brahma is equal to six hundred and sixty six years and eight months; 216,000 such lavs comprise one ghadi, and ‘thirty such ghadis make a day of Brahmā, which is the equivalent of our 4,320,000,000 years.’
The Indian philosophies provide us with a different perspective on time. While typically western scientists such as Newton, Einstein and Boltzmann view time to be linear, it is notably Indian philosophies that provide us with the unique perspective of cyclical time. It is quite unlike what modern scientists have speculated upon, but nevertheless, should be regarded as equally plausible. The problem arises in the sheer variety of theories, while Nyaya-Vaisheshika believes time to be an ‘eternal category of existence’, Advaita Vedanta perceives it as an illusion. The Jain philosophical approach regards time to be created of time atoms while the Purans see it to be created from cosmic cycles. And this is merely the tip of the iceberg; there is still a vast array of interpretations regarding time interwoven into the fabrics of Indian philosophy. Thus a study of these philosophies, although leaving us wiser that we initially were, does not provide us with a definitive result.
7. CONCLUDING REMARKS
It appears that there are a wide variety of theories on the concept of time, each with equal gravitas. Before Einstein, Newton’s theory of absolute time was the most widely accepted, but now space-time seems to have taken the limelight. Both Boltzmann and Lloyd, backed with their own equations and proofs, seek to understand time’s arrow, one through entropy and the other through entanglement. While St Augustine and Plato assume time to be linear, the Purans take a unique approach and declare it to be cyclical. The enigma of time has perplexed the greatest physicists and philosophers for centuries and each in their own right have their own distinct (and sometimes contradictory) views.
The field of physics is moving in a new direction with theoretical physicists meticulously attempting to find the glorious ‘unified theory of everything’, the theory that will hold the key to the universe and explain so many of its enigmas. Many speculate that the key lies in the theory of time, and that once that is solved, everything else will fall into place. But where does one begin? As we can see from this paper, the sheer variety of theories suggests that the possibilities are limitless. There are so many perceptions of time that despite advances in both the fields of physics and philosophy, the theories keep expanding. Which one holds the truth?
Only time will tell.
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Bhugol Khagol, Ahembdabad, Svāminārāyaṇa Aksharapīṭha, June 2010 Vachanamrut,
- Isaac Newton, Philosophiae Naturalis Principia Mathematica, rev. Florian Cajori, (Berkeley: University of California Press, 1934), 6-12. ↑
- Stephen Hawking. A Brief History of Time (New York: Bantam Books, 1988), 20 ↑
- Aryabhatt. The Aryabhatiya of Aryabhata, trans Walter Eugene Clark (New York: University of Chicago Press, 1930), 64-66 ↑
- Adam Frank. About Time (United Kingdom: Oneworld, 2012) : From Sun Dials to Quantum Clocks, How the Cosmos Shapes Our Lives – and How We Shape the Cosmos., 134 ↑
- Ibid. ↑
- Here ‘time freezes’ or ‘freezing’ of events refers to the situation where all events are completely frozen while time continues to move forward ↑
- Saint Augustine.(Project Gutenberg, 2002) The Confessions of Saint Augustine, trans E. B. Pusey Book XI ↑
- R Nave, accessed June 28, 2017,“Second Law of Thermodynamics,” http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/seclaw.html ↑
- Natalie Wolchover, April 16, 2014.“Time’s Arrow Traced to Quantum Source”, Quanta Magazine, ↑
- Ibid ↑
- Anindita Niyogi Balslev Indologica Taurinensia 12 (1984): 39-48.“An Over-all View of the Problem of Time in Indian Philosophy” ↑
- Ibid ↑
- Ibid ↑
- For example in (Benares, 1974 Cituksha’s Tattvapradipika ) and (Chowkhamba Sanskrit Series, 1970)Sri Harsa’s Khandanakhandakhadya ↑
- Approximately 1/150th of a second ↑
- Bhugol Khagol, (June 2010) ↑