Inspired and Blessed by Bob Acebedo
Inspired & Blessed

What Is Time? Is Time Travel Possible?

Jun 25, 2022, 12:08 AM
Bob Acebedo

Bob Acebedo

Columnist

Time and again, the timeless mystery of TIME befuddles me no end.

As it is, to my modest appreciation, we cannot actuate a comprehensive grasp of the entire nature of time. Suffice to adduce, we can only understand time through its attributes, characteristics, or properties like, among others – it has flow or movement, as in a river; it has direction, always proceeding forward into the future; it has order, one thing after another; it has duration, with a measurable period between events; it has a dimension, something like space; and finally, for some or most, it has a “privileged present,” or only now seems to be real.

Back in my seminary days, I have had scanty learnings about the philosophical delineations, if not underpinnings, of time, save for some basic notions like those of Parmenides and Heraclides of Ponticus, both of ancient Greece.

Parmenides believed that time is not absolute and reality is timeless. He said that the way we should think about the universe is that it exists with unique objects which simply change their state and time, but it is the same object from one moment to the next.

Heraclides of Ponticus said that “you never bathe twice in the same river,” contending hence that it’s not the same object or reality for each moment of time; that each moment in time is completely a different or new reality.

Gleaned from my past leanings, my understanding of time gravitated to the widely accepted notion that the past is immutably fixed and the future is partly undefined. And as time passes, the moment that was once the present becomes part of the past; and part of the future becomes the new present. In a word, my concept of time then was linear.

Now, visa-a-vis the strident and shifting contemporary philosophical ruminations about time, let me try to unravel – or, at the least, identify – the various issues or theoretical underpinnings related to time in a simplistic fashion as I can.

First, is time in relation to events or tangible reality. The underpinning question here is: 

“What if one day things everywhere ground to a halt? What if birds froze in mid-flight, people froze in mid-sentence, and planets and subatomic particles alike froze in mid-orbit? What if all change, throughout the entire universe, completely ceased for a period of, say, one year? What will happen to time?”

There are two camps or schools of thought that come to the fore to answer such query: On one hand is Platonism or “absolutism with respect to time,” represented by Plato, Newton, and Galileo; on the other hand, is reductionism or “relationisim/relativism with respect to time,” represented by Aristotle, Leibniz, and Einstein.

Platonism or absolutism considers time as independent of events or change, or that time can remain the same even if the way events are distributed in time changes wholesale. On this view, time is like an “empty container” into which things and events may be placed, but the container is independent of what is placed in it.

Reductionism or “relationism/relativism with respect to time,” argues that time is not independent of the events that occur in time, and that all talk that appears to be about time can somehow be REDUCED to talk about temporal relations among things and events.

Leibniz, in denying the existence of absolute time, argued that “the existence of absolute space or time would lead to violations of the principle of sufficient reason and violations of the identity of indiscernible” – claiming that between an “actual world” and a “one-second-late world, there could not be any reason why one exists rather than the other.

In the contemporary milieu, American physicist Kip Thorne, an expert on Einstein’s Theory of Relativity, believes in the relativity of space and time: “Your time flows at one rate and my time flows at a different rate. What you see as space, I may see as a mixture of space and time.”

Second issue is in terms of topology. Here, time may be, on one hand, linear, or that it is represented by a single, straight, non-branching, continuous line that extend “without beginning or end” (Aristotle); on the other hand, non-linear or consisting of multiple time streams, closed loop or a branching shape (perhaps to allow for the possibility of time travel or an open future).

Aristotle has argued roughly that time cannot have a beginning on the grounds that in order for time to have a beginning, there must be a first moment in time; but in order to count as a moment in time, that allegedly first moment would have to come between an earlier period of time and a later period of time, which is then inconsistent with its being the first moment of time. Aristotle argues in the same way that time cannot have an end.

Third issue is whether time is past-present-future or present only. The contending schools of thought here are: Presentism versus Eternalism.

According to presentism, it is always true that only present objects exist, and that no objects exist in time without being present; abstract objects might exist outside of time.

Eternalism, however, contends that objects from both the past and the future exist. According to eternalism, non-present objects or persons like Socrates (of ancient past) and future Martian outposts exist, even though they are not currently present. We may not be able to see them at the moment and they may not be in the same space time vicinity that we find ourselves right now, but they should nevertheless be on the list of all existing things or beings.

Fourth, is in relation to space and passage of time, again with two opposing camps: the Static Theory of time versus the Dynamic theory of time.

The Static Theory of time posits that time is “like space.” and there is no such thing as passage of time. Static Theorists may admit that time seems to pass, but they insist that it is just a feature of consciousness – of how we perceived the world – and not a feature of reality that is independent of us.

The DynamicTtheory of time states that time is very different from space, and that the passage of time is a real phenomenon, and each moment is uniquely a “temporal becoming.”

A hybrid of the Static Theory and Dynamic Theory is the Moving Spotlight Theory, which uses the metaphor of a moving spotlight that slides along the temporal dimension. To my understanding, this may be akin to the Sun’s “spotlight” traversing through the Earth’s rotational axis of 24 hours, thus making it day on one side of the globe and night on the other side and with different timelines or positions in time.

For the Static Theorist, there is no difference in time or no passage of time, between us in Manila at 11 a.m. and in New York at 11 p.m. because the static fact remains that in terms of “space” both Manila and New York are in the same or simultaneous unified spatial reality (only perhaps that we’re awake here in Manila because it’s day and those in New York are asleep in the night). But, for the Dynamic Theorist, Manila and New York are of different positions in time, noting likewise that both are different in space.

As a hybrid, therefore, the Moving Spotlight Theory is like the Static Theory in that it incorporates the idea of space-time as a unified manifold and with past, present, and future parts of the manifold all equally real; it is like the Dynamic Theory in that it incorporates the thesis that positions in time (so called “A-properties”) are objective and irreducible properties and that time genuinely passes.

Fifth issue is whether time is “real” (fundamental) or just an “illusion”.

Let’s take the first camp: time is but an illusion. In a famous paper published in 1908, J.M.E. McTaggart argued that there is in fact no such thing as time, and that the appearance of a temporal order to the world is a mere appearance.

In the modern arena, Hugh Price, a Bertrand Russell professor of philosophy at Cambridge, affirms that time is but an illusion. For Price, time is not real or fundamental that exists in the physical world because it is impossible for something temporal to emerge out of something a-temporal, and that our notion of time is only a product of our subjective temporal perspective.

Price explains:

“We have such ideas about the properties of time. There’s the idea that there’s a special present moment; the idea that there’s some kind of flow or passage of time; and the idea that time has a fundamental direction. But these so-called properties of time are really not part of the physical world, but are coming from us.”

But the second camp, represented by John Pokinghorn, a quantum physicist who later became a priest, argues that time is fundamental or real: “The time-is-illusion theorem is a mistaken argument because no observer has knowledge of a distant event, or the simultaneity of different events, until they are unambiguously in the observer’s past...therefore such argument can just entirely focus on the way observers describe the past, but cannot establish the reality of the awaiting future.”

Pokinghorn gives another reason why time is fundamental and not an illusion: “If space and time emerged from something more fundamental, what would that do to the fundamental nature of time? I don’t think it would remove the fundamental nature of time. After all, matter and energy emerge in the same sort of thing, and we don’t think they are illusions. We’re not made of illusions ourselves.”

Meanwhile, I find it most interesting Pokinghorn’s understanding of time from a theological point-of-view, with the premise that we live in a world of ‘unfolding becoming’:

“If there is a God, how does God experience time, if at all? The classical view was that God saw the whole of creation all at once. In scientific terms, God saw a block universe, the space-time continuum. But I don’t think that’s right. I think we live in a world of TRUE BECOMING (underscoring mine) – that is to say that the future is not there already waiting for us, but WE MAKE IT OR HELP TO MAKE IT AS WE GO ALONG (underscoring mine). Of course, God is not enthralled to time; there must be a timeless, eternal, unchanging aspect of God. But I believe that when God brought into being a universe endowed with time or endowed with becoming, God in a way chose to know that world according to its nature and its becomingness.”

Finally, one last query: is time travel possible?

Naysayers put forward three arguments that time travel is not possible. The first argument says that time travel is not possible because it violates the laws of logic and metaphysics, as demonstrated by the following argument (sourced from Standford Encyclopedia of Philosophjy):

1. If you could travel back in time, then you could kill your grandfather before your father was ever conceived. (For what’s to stop you from bringing a gun with you and simply shooting him).

2. But, it’s not that case that you could kill your grandfather before your father was ever conceived. (Because if you did, then you would ensure that you never existed, and that is not something that you could ensure).

3. Ergo: You cannot travel back in time.

Another argument that might be raised against the possibility of time travel depends on the claim that presentism is true. For if presentism is true, then neither past nor future objects exist. And in that case, it is hard to see how anyone could travel to the past or the future.

A third argument, against the possibility of time travel to the past, has to do with the claim that backward causation is impossible. For if there can be no backward causation, then it is not possible that, say, your pushing the button in your time machine in 2022 can cause your appearance in, say, 1800.

However, many scientists and philosophers believe that the actual laws of physics are in fact compatible with time travel.

Also, another basis for the possibility of time travel, according to some, is the fact that time travel stories – like the one depicted by the movie, “Timecrimes” – do not cause any particular cognitive dissonance.

Ah, time or no time, absolutism or relationism, linear or not, present or eternal, static or dynamic, real or illusion, and time travel possible or not – in the final analysis, for me, what is more exigent and fundamental, more than cracking one’s head on the nature or reality of time, is SPENDING my life meaningfully and satisfyingly in my relationship with God, with my significant others, and with the world.

Have a wonderful TIME!


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