Meeting Yourself Coming Backwards

An unwelcome message from the future.  This Magnum edition published 1977 in association with Eyre Methuen Ltd.  Cover illustration by Tony Roberts.

An unwelcome message from the future. This Magnum edition published 1977 in association with Eyre Methuen Ltd. Cover illustration by Tony Roberts.

It is difficult to get your head around the concept of time.  In Odyssey 39, which has just been issued, we make a brief excursion into this field, and ask a few questions along the lines of whether time even exists.  Science fiction writers have often played with the idea, frequently in the realm of stories about time travel itself.

There have been plenty of arguments that actual time travel will always prove impossible, not least because of the familiar “grandfather paradox” it would create.  Travel back in time and kill your grandfather before he met your grandmother and you’ll never be born – so you won’t be able to go back in time and kill him – so he won’t die and will indeed meet your grandmother – so you will be born and be able to go back in time… etc, etc.  You know the way it works.

However, the hypothetical particle known as the tachyon raises a serious question on this subject.  As is well-known, the theory of relativity does not say that nothing can travel faster than light – it only says that nothing can travel at the speed of light.  So a superluminal particle – the tachyon – which never slows down to light speed is feasible.  The added complication is that it travels backwards in time.  Now, although this doesn’t actually infer the potential to travel bodily backwards in time, it raises the (admittedly remote) possibility of sending signals into the past.

Gregory Benford’s Nebula Award-winning 1980 novel Timescape stands out as a story where these issues are debated.  Messages from the future must be carefully phrased to prevent any possibility of a grandfather paradox, but even then all doesn’t go according to plan.

We see something of the same dilemma in Clifford Simak’s classic 1951 novel Time and Again.  A message from the future says that a book which has yet to be written will lead to warfare and the deaths of millions in years to come.  But then, if the message can come back in time, why not the entire contents of the book itself, which is indeed what seems to have happened in the story.

If you follow through this line of argument, you question whether anyone actually needs to write the book in the first place.  In fact, some altruistic people in the future might be so kind as to send back not just a single book but their entire worldwide database of information.  Then we won’t have to go to the trouble of writing any of it ourselves.  If they would then helpfully send back their full historical records, we can ensure that many, if not all, of the problems in our future can be circumvented before they happen.

But then, of course, the first time we take any action based on that information, we are altering the history of those nice people in the future, and so their past won’t be the same for them anymore.  Quite possibly, they may not turn out to be quite so nice after all.  Or, more to the point, what we ourselves then live through won’t be the past of those same people who sent us the information.

James P Hogan’s 1980 novel Thrice Upon a Time gives a picture of the alternate timelines that might inevitably be established once changes to the past are possible, no matter how rigorous the controls over the system.  Alternative histories and parallel worlds spread before us.

And that, needless to say, is another subject.  For another time.

Richard Hayes, Assistant Editor (Odyssey)

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