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and the 5 Biggest Problems With Time Travel
Alan R Graham is author of the philosophy of science proposal, Time's Paradigm, unraveling the myths and mysteries of time.
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Article: Dec 16th, 2019
Let's define this gargantuan beast before we get to the reasons why Time Travel has problems... We are all traveling through time on a daily bases from the past to the future. Put that way, we are all time travelers. Secondly, all of our time-pieces like phones, watches and mirowave ovens are ticking along at different speeds - so says Relativity - which means some of us are growing old faster than others. Is that Time Travel?
Time Travel, problems or otherwise, is most notably the realm of science fiction, more often than not the word 'fiction' meaning "anything goes". For that reason, scientists, philosophers and the like, rarely dip their toes in this steaming pot of molten jellybeans - they have reputations to uphold.
Not to worry. Writers to the rescue! Enormous contraptions are usually employed to transport a time traveler back or forwards to an alternate date. This is where liberties are taken by scribblers and the 'science' falls short on fact. It may become possible in the future but with today's understanding of the physics, in the foreseeable future time travel is highly improbable.
Nevertheless, it will happen one day so it is appropriate at this juncture to present a Time Traveler's Guide for those on the cusp of venturing forth - or considering such an endeavour. Besides, physical time transference isn't the only fashion these days.
Yes, there are a number of other ways to visit alternate dates in time without giant, teleportation devices or Aliens. Like subconscious dissociation, chronosthesia and sensory deprivation, which are much more promising with current knowledge, but alas they do not get the attention they deserve. However, just occasionally we get treated to something exceptional, as recently happened with the publication of "The Time Travelers Wife".
Time Transference is a better description than time travel for "getting about" in time: disengaging with 'now' and popping up somewhere else like yesterday or tomorrow. Alternatively, a time traveler might remain in the 'now' and have a doppelganger do the traveling. Take your pick. He/she/they/it might be the same age on arrival as when they departed or they might not. Does it matter? How long it took them to get there is, well... irrelevant. There are no rules as yet, so writers: Go Nuts! The only prerequisite, it seems, is that Time Travel be non-sequitur, Which belies causality, but isn't that the fun part?
There are 5 big problems with Time Travel, so before you begin criss-crossing the galaxy, take note; this Time Traveler's Guide is easy to read and devoid of any large chunks of scientific jargon. A monkey could understand it. Buckle Up!
The rules are simple, it's just like flying a plane - there's a check-list for everything.
Don't forget to take pictures...
The big issue for most would-be time travelers is proving it! Hopefully you didn't morph off without figuring out how to get back? However, even if you only had a one-way ticket you will still probably have some proving to do to the folks back in 1984.
So let's see what all the fuss is about...
No 1. The Time Continuum Paradox is a Hoax
A time traveler goes back in time and kills his grandfather, thus terminating his family lineage and making it impossible for him to have been born. Sounds plausible, and makes for a great story. But what parameters must be resolved in order for this 'Grandfather Paradox' to actually make real sense. The Time Traveler's Guide check-list of things "not to carry with you" - No. 1: Guns.
Most of us are familiar with this standard sci-fi version, of messing with the sequential continuum of time, a puzzle which has captured the imagination of writers and Hollywood directors for more than a century. Firstly, a curious anomaly usually arises in these cases, where one moment of time can have duplicate individuals running about. They may even come face to face with one another: Younger and older versions of the same person existing at the same time. "Back To The Future", the quintessential Hollywood time travel trilogy, is full of such fanciful scenarios, brilliantly told and masterfully filmed.
However, stuffing an already crowded planet with more junk in the form of a human being from another time that is not supposed to be in this present moment is an extraordinarily liberal concept, with an undeniably implausible bases in scientific reality. Has our time traveler not just altered the entire cosmos, merely be materializing in a moment he was not entitled to be in, and taking up space? One cannot just add matter to a closed system. What about all the other atomic particles inhabiting that very spot? A nuclear explosion springs to mind.
Energy cannot simply be thrown in the pot, it doesn't come and go at the stroke of a pen; energy (matter) is perpetual and entropically devalues as it changes state. Things don't just materialize!
Never mind, we film buffs and midnight oil burners don't really care; it's all about entertainment value, who gives a toss whether it actually works?
Yup. In no way should we disrespect the awesome productions of such films as, Terminator, or Twelve Monkeys, both of which were phenomenal works of art and highly praised as classics. That the concept of traveling in time or how it worked was not addressed scientifically is not an issue, as there are no rules when applying imagination and liberties can thus be taken.
You need more reasons why time travel is such a giant headache?
Time is not the exclusive domain of physics. It has a broad spectrum, encompassing, notably, the disciplines of philosophy and psychology, and so any theory on how time works must engage with all three.
For philosophy we have these: 'Presentism' vs 'Block Theory' - your choice. Presentism supposes that there is no past or future, we simply exist in the present. Block Theorists consider that all of time, the past and the future exist all at once, and that the present moment of supposed flow is just an illusion.
Have you got an alternative theory? If not then we will rely on the renown postulates highlighted above.
Well, if the past and the future do not exist, then time travel is impossible. There is no time continuum to worry about; that's that! The past has melted away, there is nothing to go back to, it no longer exists. The future is yet to happen; you can't make it appear to exist until it actually does, for everyone. To think that you and your time traveling buddies have the power and authority to create stuff like New Years Day 2048 is a bit of a stretch.
You cannot choose your way through time travel like the average person does living day to day. Choices denote a present moment in time that has no future, until you make a decision, and thus your fate unfolds based on your own free will. Good thing you are reading The Time Traveler's Guide... here's more:
Alternatively, if the past and the future already exist (the Blck Theorists) then wherever you time travel to you have already been to... and your visit has already happened. Nothing can be changed. You can't just turn up somewhere, as if that moment had not existed without your traveling persona ever having been present. No, all of time exists now. So what would be the point?
Adding to this problem with time is the fact that there would eventually be billions of versions of you all piling up at a single point in time. By traveling back in time to 1984, you will do so continuously if all of time already exists. Every 'you' on your timeline that reaches the moment of departure will end up in 1984, so an infinite number of duplicates will emerge. We could counter this by suggesting it is only our consciousness that actually travels - again, what would be the point if all our thoughts have been predetermined?
So, back to that Time Continuum Paradox. Either way you look at it, Presentism or Block of cheese, there's no killing old Gran'dad. Time Travel is just not possible and verging on pointless. No Time Continuum Paradox.
No 2. Going Back In Time By Traveling Faster Than Light
Following on from the theme above, if all of time already exists then our awareness of this present moment is just as pointless as traveling to another time and being conscious there. Nothing we can do makes any difference to our outcome.
If you shudder at that thought then you will probably opt for the more comforting alternative which involves free will and lots of choice, and that "there is no fate but what we make" (Terminator - 1984).
Okay, back to the nuts and bolts of physics. Quantum Mechanics can do it, or at least some of their particles enjoy the privilege of hopping about in time. They just haven't yet been able to employ it on an industrial scale. Then there's the fanciful notion that one day astronauts will be time travelers.
It has been widely suggested that surpassing the speed of light might offer us the means to time travel, by setting our clocks in reverse. So the second thing on the check-list of items needed in The Time Traveler's Guide is a good watch. Not any old watch, mind: Preferably an Atomic Clock and a flashlight, for fun.
Yes, Relativity suggests that our clocks slow down as we approach light speed, so only natural to assume that as we reach it, our clocks stop - and then what, the unthinkable..! For some this immediately suggests that we could be heading back to 1984. This is de-synchronization, not non-sequitur time travel; slipping away from the present moment by slowing down or speeding up. While we might be living our lives in reverse, walking backwards, eating backwards, we are still abiding by certain constraints imposed by time and are in contact with the wider universe.
That we might abruptly whiz off at incredible Warp Speed down a giant wormhole is just more fanciful hocus-pocus!
To begin with, and from a philosophical standpoint, time cannot flow backwards. To use such a word implies an opposite direction, i.e. "forwards". Time may have a course -- if such a notion can practically apply -- but precisely retracing steps taken is impossible as this would run contrary to causality. Positive momentum occurs, there are no negatives in physical nature, deceleration is a misnomer - it's negative acceleration. In considering an expanding universe which may eventually collapse in upon itself, contraction would not be an identically opposite phenomenon. Deflating balloons do not collapse in reverse. Energy does not flow backwards... sorry.
Ah, they say, time will continue on, we will simply plunge into a wormhole.
Oh... so now time doesn't flow backwards in order for us to get sucked down a wormhole. Make up your minds!
Haven't we already been told by Einstein that reaching light speed is impossible..? You need an infinite amount of energy/mass to get there which, clearly, ain't happening. With one exception, if you get to close to a Black Hole - they, I might add, being all a few thousand light years away!
Cutting through all that 'red tape' and arguing that a wormhole will reduce time and distance to nothing is a fairy-tale shortcut with obvious appeal. It cannot be substantiated, it plays parallels with the Mobias Strip, and supposedly has theoretical scientific validity, of sorts. But I wouldn't count on it, as first you will need to get to light speed which, in itself is a monumental task.
Creating a wormhole in the lab seems much more appealing (see below). What more do you want, as a writer or director? And yet, to this day we have difficulty reaching six miles down to the bottom of our deepest oceans. We have only in the last few years created a craft capable of reaching the limits of our tiny Solar System. However, time travel is no problem, we'll be skipping about in a matter of decades, so it seems!
What about traveling into the future? Besides the fact that returning from a trip to the past requires that we travel back to the future, forward flights of fancy are rare. I mean, wouldn't faster than the speed of light get us there faster?
We are forever obsessed with changing our destiny by traveling into the past but rarely do we encounter a theory that involves messing with the future on its own turf. We could just as easily rearrange things for a positive outcome by zipping forwards in time to, say, next week! Like, pulling your resume from the bottom of the pile and dropping it on top. Then, a few days later, waiting for the phone to ring.
The fact is, we are already traveling into the future so accelerating our progress might be a lot easier than trying to slow down and go backwards. If traveling at the speed of light freezes our clocks, what about stopping moving altogether? Would we not shoot forwards through time at an incredible rate? Science has dismissed such ideas with a big yawn so writers have very little substance to plagiarize. What a shame; Relativity is soooo restricting. (see below for Zero Velocity Experiment).
No 3. Why Don't Time Travelers From The Future Show Up Today?
So we are stuck with visiting the past. How far back? The common consensus is that once we have figured out how to Time Travel the sky's the limit. A day, a month, a millennium or more - wherever the story takes us we will follow, no issue.
A nagging question: why haven't time travelers been popping up all over the place in our life time, as one would expect if such journeys were to become possible? Isn't it reasonable that in all likelihood, a device of some kind will, eventually, be designed to transport us back in time? Yours, perhaps...
It would likely take enormous amounts of energy to power such a device. It would be unrealistic to assume that time travel was going to be a cheap affair. Equally, it would be realistic to assume that the further back one wished to travel the more energy would be required, eventually making it practically impossible to reach too far into the past.
Then there is this: where exactly were we yesterday? All things in our Universe are in constant motion. The planet beneath our feet is likely traveling at near 2 million miles per hour as it journeys not only around the sun but around a galaxy that is, in itself, traveling at a colossal speed towards another. So, yesterday you may not have been where this Solar System now is, at all. Time Travel is not just about finding a path between one moment and another, but also between locations in the Universe whose distances might become immense the longer we wait, making our efforts to achieve Time Travel even more costly.
One need only look at the CERN Collider, its size, its personnel and its consumption, for a glimpse at the resources necessary to accelerate a single proton with absolute precision to relativistic speeds.
The nearer we get, therefore, to the date when the art of time travel has been mastered, the more likely we are to be visited by folks from the future. At present it would appear we are still some way off. Aren't we..?
And, yes - well - the argument for Time Travelers is that they probably don't want to be spotted. It is safe to assume that the majority will be government agents tasked with some secret agenda. Only governments would have the financial clout to get such a project up and running.
... Tourism will take a bit longer.
The Time Traveler's Guide carry-on check-list: 1. Gray clothing; 2. Hat or mustache.
No 4. Multi Worlds And Super Universes - Yes, indeed.
The future does exist, says a branch of physics, every possible direction we might wish to take is already out there and, yes, we can choose which path we wish to take: An infinite number of parallel worlds all written down and waiting.
Well, it satisfies the sense of control normally associated with complex structures and at the same time allows us autonomy. Great! Never mind how we are supposed to travel between them, for the moment.
You see, there are two problems with this theory. The first is logical, the second statistical:
Saying that every possible outcome is already out there, implies that the past is the same for all of them. Even as the present moment continues to march on. Bizarre.
Secondly, if every possible scenario is out there for us to experience, then not only the sensible variations but also the insane ones will exist. A chicken could lay a million eggs in one night, for example. However, such wacky things don't really occur. Or do they?
Some very strange things do happen, but far fewer than would seem reasonable if absolutely anything were acceptable. (NB. If the universe is infinitely old then the gap between strange things happening could be many hundreds of years). However, imagine if the laws of physics could be seriously tampered with as we sailed along on our merry way through time. It has been suggested that a barrier might be set up within this theory of parallel futures to avoid the unthinkable, to protect the laws of physics. Hmmm, grasping at straws if you ask me...
Quantum pysicists came up with this theory for making sense of some of their most bizarre conundrums. It' called 'MWI' the Many Worlds Interpretation, whereby all future time lines exist and therefore all future possibilities are open to travel. Does that mean that all past time lines also exist? Or, is there only one now firmly cemented in history? Therein lies the Achilles heal of MWI; it talks only of future possibilities and does not adequately resolve the concept of past existence, as if all possible past time lines merge into the present single moment, before bursting out with all possible future events - a Bow Tie scenario.
The check-list for carry on luggage denotes: Cat food. You never know..?
A cat - yes, a cat - in a thought experiment was specifically created to confront certain Quantum irregularities and MWI was employed to answer: particles that have all their possible states in readiness at all times but only show one when it is observed.
Schrödinger, metaphorically, puts a cat in a box with a sealed jar of poisonous gas and a device that will break the jar if it detects a particle changing state. As far as quantum mechanics is concerned, at any time in the near future the cat is both alive and dead, until we open the box to see. Thus, the MWI adequately explains this cat paradox, by saying, "Each possibility has its own place in the future, simultaneously," namely, a superposition of states.
We have choices with many possible outcomes, in the view of quantum physicists and the sub-atomic world. But the past is anyone's guess.
Oh, well! That means only the future exists. How odd, when surely the present is the future's past..? It might be interesting to visit a future that you didn't actually take, from a scientific or anthropological stand-point, however it doesn't really solidify the argument for Time Travel. Visiting an alternate reality is like going on vacation, hardly traveling through time.
But wait! What about another universe? Doppelgangers have been suggested, as has a scientific thesis suggesting that the Big Bang created two identical universes, one flowing forwards through time and the other backwards, for equilibrium. Well, like the section on light-speed, first you are going to have to figure out how to get there, never mind how you are going to handle walking backwards. Time Traveler's Guide check-list: Wheelchair.
No 5. You Cannot Surprise Yourself In The Past Or Future
If Presentism has its way then Time Travel is not possible. If the past and future already exist and we fantasize that we are free to interact with them, then what kind of surprises are we in for..?
You cannot sit at an empty table and then decide a few minutes later that you will surprise yourself in that past moment by sending back a plate of scrambled eggs. While you were sitting there in that past moment the eggs would have arrived. No surprise.
Does this mean you can now screw up the future by stopping yourself from sending the eggs? Also absurd: no idea to surprise yourself ever materialized; you never sent the eggs. Or, maybe it wasn't you that sent them..! So, what stops you from surprising yourself in the past, with something you know never happened? One possible answer: You are not as brilliant a temporal physicist as you thought you were.
What if a government official decides that, tomorrow he will send an assassin back to kill his despotic dictator, today. This afternoon, he watches his assassin shoot the dictator. Now, he thinks, I don't have to send my assassin back tomorrow, the deed has already been done. He must have done it, but now he can choose not to. This scenario may sound like a winner for Presentism enthusiasts, however, with serious contemplation we can always arrive at the same conclusion: personality.
If he decided to play this trick on Time before the assassination, it never happened. If the idea suddenly occurred to him after the assassination, it never happened. Why didn't his plan work? Because that's the kind of man he is!
Future time travel is less complicated. If a traveler leaves his present moment for some future date, we can assume that he no longer exists with others in that present, unless we accept the magical 'split' phenomenon mentioned above. So, when he arrives in the future he will not be able to meet himself as his earlier self did not continue on in standard time progression. He could return before he departed and warn his past self of impending future disaster, but he would only be telling the self that will soon time travel into the future. A never ending loop of time going nowhere: What good is that?
A permanent marker has been added to the Time Traveler's Guide check-list, to dot your forehead, like marking trees along a trail so you know where you are, literally.
Being able to choose your way through time excludes the possibility of time travel. Not much of a film plot for Hollywood!
On The Bright Side - Time Travel, Please.
Recent interest in alternative theories of time have brought into question older models, such as Relativity. Time and our universe, they argue, may not have started with a Big Bang - instead, time cycles, with no beginning or end. Superluminal velocities may be possible and multi-worlds might rise again.
Time does not stretch out forever, from an infinite past into an infinite future on a flat, linear model like a ruler. Time revolves, it cycles, a continuous circuit. In every aspect of our lives we live in never ending loops; a day is twenty four hours and then we start again. So, if we could separate or split ourselves from this cyclical flow, we would simply create a smaller cycle or loop, into which we, the time traveler would become for ever engaged.
Time Travel is not out of bounds, it could well become a reality. Just how? Temporal Perception and our cognitive awareness of time is an area little explored as a means of non-sequential time travel.
Suppose we look at time like this: There is no such thing as physical motion. We move only in time, and as we progress from one moment to the next we simply perceive that we have moved in space, because all of time and our whereabouts already exists.
Suppose we accept that we are, as individuals, aware throughout our time line, we flow seamlessly from one moment to the next as an entity, we are everywhere along its length, alive and existing and interacting with our surroundings at any moment; and so no time traveler can suddenly or simply appear to alter what has already been dictated as fact. Is it not more likely then that traveling in time would be a conscious function and not a physically altered phenomenon. Might we not succeed in the future to slide our awareness of self through time rather than our physical form?
Gone will be the days of clunking and whirring contraptions, giant revolving portals and fizzling globes of energy. H. G. Wells and his beloved "Time Machine" must now give way to a more modern approach, where lab coats and clinical sterility might one day whiz a comatose guinea-pig back to Time's Square and 1984, with no ill-effect on the cosmos, and no time continuum paradox.
Alternatively, just assuming that physics catches up, we may actually have the wherewithal in the next century or so to create the means for Time Travel. Not with a wormhole or a black hole, but a White Hole, capable of reversing our speed through the universe to zero velocity. Then instant re-emergence - at the speed of light - anywhere we choose and at any time.
A theory, yes. You will find it in part six of the book, Time's Paradigm. Read online or download the ebook, for free.
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Time Travel in the "Hollywood" sense is unlikely
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