Something
always bothered me about the idea of time-travel, especially in science
fiction stories. There are the usual time-paradoxes, of course – going
back in time to kill your ancestors before they could meet and mate,
thereby making the whole exercise of you coming into existence and going
back in time to kill your ancestors impossible1 – but there was something else… something I couldn't quite
put my finger on, that vaguely annoyed me from behind the shadows of my
fuzzy understanding. Perhaps this is obvious to others - especially
more avid readers of Sci Fi - but it
took me a while to realize what exactly was troubling me. I finally managed to identify it now; and to bring my confusion out
from the shadows, and hopefully present it clearly for all to see, I
created the following story.
The story is the set in the mythical land of Kaalifornia - a magical place where wondrous, magnificent angels be - a place where the majestic, capricious wheels of time take many a mystical twist and turn. It is the story of a certain Mr Time Cruise (Tim, for short) – and his adventures and misadventures as he attempts to navigate the powerful currents of time.
Our story begins with old Tim standing at a certain point on a certain line. The time-line, it is called. This line, we are told, represents an 'objective'2 metric of time. It is a long, long line - no one knows quite how long... some say it extends forever in both directions. All beings walk their path on this mystical line3. For our walking convenience, a series of plancks been laid out, covering the whole time line. Each planck is numbered, so we know exactly where we are. They extend - or so we are told - from -infinity to infinity4.
Now, according to our experience, time has this sensation of flowing - we feel in some way, to be proceeding along time in the direction of what we call the future. Assuming Mr. Cruise to be a normal, sane person (that is, only as crazy as the rest of us), we assume his experience conforms to ours, and the above is what Mr. Cruise feels too. So our good friend Time Cruise finds himself happily cruising along the time line, from present – to a new present – which is actually the future to a past that was the previous present. Whatever. But we know this is the sort of thing that we usually feel. We will represent his experience of the flow of time - as the action of him walking along this track from planck to planck on the time-line.
Mr. Cruise then, is somewhere on this line – to be precise - he is at the point 1985. Now, in ol' Tim's brain, there is also a record of all events that he has experienced in his 'past'. So there exists there a 'history' – his store of his story of his strolls along the shores of time.
Our story begins with old Tim standing at a certain point on a certain line. The time-line, it is called. This line, we are told, represents an 'objective'2 metric of time. It is a long, long line - no one knows quite how long... some say it extends forever in both directions. All beings walk their path on this mystical line3. For our walking convenience, a series of plancks been laid out, covering the whole time line. Each planck is numbered, so we know exactly where we are. They extend - or so we are told - from -infinity to infinity4.
Now, according to our experience, time has this sensation of flowing - we feel in some way, to be proceeding along time in the direction of what we call the future. Assuming Mr. Cruise to be a normal, sane person (that is, only as crazy as the rest of us), we assume his experience conforms to ours, and the above is what Mr. Cruise feels too. So our good friend Time Cruise finds himself happily cruising along the time line, from present – to a new present – which is actually the future to a past that was the previous present. Whatever. But we know this is the sort of thing that we usually feel. We will represent his experience of the flow of time - as the action of him walking along this track from planck to planck on the time-line.
Mr. Cruise then, is somewhere on this line – to be precise - he is at the point 1985. Now, in ol' Tim's brain, there is also a record of all events that he has experienced in his 'past'. So there exists there a 'history' – his store of his story of his strolls along the shores of time.
As our friend ambles along - quite unaware to him - a little farther down the track - lurks a singularly catastrophic creature ... a creature so dreaded that the whole of space-time trembles to the very core of all 11 of its dimensions when it encounters this horrendous beast.
It is a worm.
A worm with a hole.
A wormhole.
Tim walks right up to the worm... and steps right into the hole.
Space collapses.
Time elapses.
But, in reverse...
Space collapses.
Time elapses.
But, in reverse...
For when it comes time for the time-reversing hole to emit Time out, he finds himself in a now, which a now in which he had been a moment ago(?), would have considered a now that came prior to a very long series of nows indeed. Tim is now, in the past.
To be precise - he is at point 1955. Of course - he continues feeling the passage of nows, every now - so his (very sane, as we've have been careful to point out) mind experiences still, that constant flow of time. Shaken, but determined, he marches onward, displaced in time from where he was before(??) he fell into the wormhole, but proceeding along the same time-line, in the same direction - at what we will assume - if it makes any sense - the same pace. Onward to points 1956, 1957, 1958 and so on.
Tim is strolling along a deserted trail... weary and worn; lonely, forlorn... when his eyes fall upon a most enchanting image - a timeless creature of striking beauty. Her name: Whensearch (When, for short).
Time has been very kind to the ageless When. And now it is time for When to be kind to ageing Time. She invites him to rest and replenish in her oasis. Our weary traveller is instantly attracted to his hospitable hostess. He nervously asks her out. A date with Time? Why not?, thinks When.
When has always been searching for time - and now she finally finds Time. The enchanted arrow of time crosses both hearts... and begins an endearing romance. Many joyous dates pass... hours that seem like minutes, years that seem like days - and the happy couple dream dreams of living together happily forever after...
Alas... this is no fairy tale... and nothing here does forever last. In fact, in the very arrow that made two hearts most happy - lurks the shadow of ever-escalating entropy.
For
while our beloved couple dream dreams of forever - the dreaded worm - the
very one with the hole - rears up its unwholesome head once again. And
poor Tim's next encounter of the
wormed kind is set up. Yet again does he fall through that dratted hole -
yet again is he whisked cruelly off to a time far, far away...
This time, Time is transported to the point 2015. The now at which he had been standing just before he fell into the hole would have considered this now to be a now coming after a very long series of nows indeed. It is what he would have called then: the future.
Tragically snatched away from his precious When, he is alone again, forlorn again. But his consciousness, relentless as ever, continues to move him along the continuum (discreteum?) of time - from points 2015 to 2016 to 2017 and on... As he ambles along the shores of time, Time, tired of all the walking, pauses to admire the horizon. He is struck by the beauty of wave(-particle)s that come to light - it is as though time has come to a stand still.
But time and tide, as we well know, wait for none... not even for the tired Time watching the tide. And the fickle zeitgeist of the ever-changing times conspires to set up a third close encounter.... with the same dreaded worm - the one with the hole... this time, transporting Time back to the time he had left his past present - back to 1985.
Our time-worn friend has been through a lot. One thing though - through the best of times and the worst of times, through times of springy hope and wintery despair, through travels to the past and back to the future - one thing, has remained a constant. One thing that Time felt each time, all the time. That is his sense of the constant flow of time - that keeps accumulating as his history in his brain.
This time, Time is transported to the point 2015. The now at which he had been standing just before he fell into the hole would have considered this now to be a now coming after a very long series of nows indeed. It is what he would have called then: the future.
Tragically snatched away from his precious When, he is alone again, forlorn again. But his consciousness, relentless as ever, continues to move him along the continuum (discreteum?) of time - from points 2015 to 2016 to 2017 and on... As he ambles along the shores of time, Time, tired of all the walking, pauses to admire the horizon. He is struck by the beauty of wave(-particle)s that come to light - it is as though time has come to a stand still.
But time and tide, as we well know, wait for none... not even for the tired Time watching the tide. And the fickle zeitgeist of the ever-changing times conspires to set up a third close encounter.... with the same dreaded worm - the one with the hole... this time, transporting Time back to the time he had left his past present - back to 1985.
Our time-worn friend has been through a lot. One thing though - through the best of times and the worst of times, through times of springy hope and wintery despair, through travels to the past and back to the future - one thing, has remained a constant. One thing that Time felt each time, all the time. That is his sense of the constant flow of time - that keeps accumulating as his history in his brain.
Let's review, then, what Mr. Cruise's 'history' (as we described it earlier) is. He was first born at a certain time - say 1961; he ambled along till 1885; was then pulled back into 1955; moved on 'normally' till 1959; was then he brutally thrown into 2015; went on normally to 2019; and then, he came back to 1985. There is a series of then-s here, quite separate from the order of time-line points he travelled across. On the timeline, he has intermittent intervals of existence – from 1955 to 1959, 1961 to 1985, and 2015 to 2019. But in his own history – his memory – the sequence is different. There is thus another dimension - a history-line, on which timeline values can lie. The fact that the history line exists, indicates an extra dimension – this was the bothersome aspect of the time-travel idea – this hidden dimension that does not usually get an explicit mention in the stories.
Having a historical verses an objective time-line presents problems for vocabulary used in sentences describing time-traveled actions, since the function (time as function of history) is not monotonically increasing, nor is it continuous. Thus if Tim went from the future into the past, the past for him occurs after the time-lined future. Since English deals with both times in the same way, these dimensions are crunched into one and the meanings of the words we use in describing time get overloaded with both historical (memory) and 'objective' timeline meanings. Words like first, then, ago, before, and after might refer to both cases.
Thus achieving clarity in describing time-travel in a tale is a somewhat complicated exercise. The (grammatical) tense for these words is awkward, since the past to a time cruiser need not really be the past, the future may have already happened, and the present… well, whoever knows what the present is?
Thus achieving clarity in describing time-travel in a tale is a somewhat complicated exercise. The (grammatical) tense for these words is awkward, since the past to a time cruiser need not really be the past, the future may have already happened, and the present… well, whoever knows what the present is?
NOTES
1. This is of course, if we believe in a single unchanging time-line. If on the other hand, we favor a malleable time-line (like in the Back to the Future movies), we might merely find our photographs fading away. Also, do we allow a person – a consciousness which records history – to be twice at the same time? Maybe only one of a person can exist at any one time. In that case, one cannot meet oneself in the past, because the one that one is going to meet is the one that is meeting the one that one are going to meet.
2. What is this 'objective' thing I mention? I don't really know. Let's just assume it exists for now.
3. It looks like we are saying there is a single 'objective' line on which everyone walks - but this is just for the convenience of writing; we could imagine each of us having a different time-line if we want to.
4. Although we use integers here, this too, is merely for expository convenience. We will leave it for later to decide whether the line should be continuous or discrete.
We will also just assume for now, that this line does extend to infinity both ways. Of course, we could have a starting point for time, for example, at the Big Bang. Similarly, we could have an ending point (2012?). What happens to time before/after these points? One answer is that it doesn’t exist: time came into existence when the Universe was created, and might come to an end if and when the Universe ends. We could also have circular time, so that time never begins or ends, but for ever and ever loops