Time travel is still used in science fiction, but not as much as when SF was in its infancy and early adolescence – much like Faster-Than-Light travel, it is generally considered unscientific.
Stephen Hawking, one of the most famous physicists of all time, said that
“…the best evidence we have that time travel is not possible, and never will be, is that we have not been invaded by hordes of tourists from the future.”
But nonetheless, time travel is still a device used in science fiction literature (though a notable overuse of this theme seems to come from media-related products), from H.G. Wells’ The Time Machine (1895) to Michael Swanwick’s recent novel Bones of the Earth (2002). Time travel is more than likely going to stay in science fiction for some time, simply because as a theory it presents too many intriguing possibilities to pass up.
However, in order for time travel to be successful as a story element, it must have limits. H.G. Wells said, “If anything is possible, then nothing is interesting.” He was warning of SF’s love for deus ex machina, in which the solution to the conflict comes out of nowhere and renders the plot struggles irrelevant. In Timeslides’ case, Lister presented the limits of time travel when he said,
LISTER: The thing is, we can’t move outside the confines of the photograph. What we see is all we get.
Causality is possibly the most important thing in time travel, for the simple reason that if someone were to go back and avert the death of, say, Mahatma Gandhi, then the possibilities would be limitless – Damon Knight, one of the most important SF critics and writers of all time, said
“…imagine trying to write a story in which anything is possible. Your central character can be a man one moment and a woman the next; she can be in Bloomingdale’s on page 1 and on top of Mount Anapurna on page 2. This freedom may sound exhilerating, but try it and see how long it takes you to become bored and disgusted.” 
But it is also true that even though there must be limits to time travel, it presents such opportunities for plot and story and intriguing settings that it can still have freedom within its boundaries, which is the reason why writers still use it as a story device today.
Time travel as a device has even been accepted by some of the more “mainstream” authors, such as Michael Crichton, whose novel Timeline (1999) involves historians in 1999 travelling back in time to the Middle Ages. Crichton isn’t a science fiction author, however, and has admitted to that many times – but that’s another story.
Grant Naylor didn’t even bother to work out any sort of plausible excuse for how this form of time travel may work. Holly’s line amply demonstrates this:
KRYTEN: I just developed the film as normal, and for some reason they came to life.
HOLLY: It’s the developing fluid. It must have mutated.
Any sort of explanation as to how or why the developing fluid mutated would have meant less screen time for the story, and Grant Naylor only had thirty minutes in which to work. It is possible, then, that some sort of explanation for the developing fluid’s abnormal behavior may have been worked out, but was cut in the script stage for reasons of time – but this is unlikely, as in most of the other Dwarf episodes there have been adequate explanations for the scientific phenomena. So it is likely that they decided to not bother working out the logic and instead enter immediately into the story.
Grant Naylor obviously had a few problems with the logic behind the episode. Craig Charles, in one of his rare moments of perspicuous thought, pointed out to Grant Naylor a logical flaw in their script. “The skiers had scripted lines about how they got Lister’s rather scary birthday snaps – which would have been fine, except, at that point in time, the skiers would not have received them yet. The lines were summarily cut.”
But time travel (or some other such premise) does not a good story make – there must be characters who drive the story, or else the premise will suck the marrow from the story and it will become another tedious lecture. The majority of the first two series of Red Dwarf show Lister as being generally happy with his situation – a few episodes from series I show that he does miss other people, but generally he seems to be satisfied, at least partially.
LISTER: I’m sick of you and your silly green suits, I’m sick of your stupid flared nostrils. I’m sick of the way you always smile when you’re being insulted. I’m sick of the Cat. I’m sick of Holly. I’m sick of you. I’m sick of me. And as for Kryten … I’m sick of him. I’m sick of this ship, sick of this life. I’m just sick of it.
The above speech adds some depth to his character – he’s clearly ready for a change, and the “mutated developing fluid” offers him a surprisingly convenient chance to change his life forever. But the limits to what can be done with time travel provide an obstacle for him – and plot is all about obstacles. He comes up with a plan to work around those boundaries and still come to the same conclusion.
Lister’s confrontation with his younger self expands on his general unhappiness with his life:
LISTER: I’ve come to try and change your future.
YOUNG LISTER: Change it? Aren’t you happy being a rock star? Is the constant demand of them groupies getting you down?
LISTER: You don’t make it as a rock star.
YOUNG LISTER: That’s impossible! It cannot be!
LISTER: How can I say this without giving offense? You don’t make it ‘cos … you’re crap.
It forces Lister to come to a realization about his wasted life, but also offers him the chance to change it. Time travel offers a unique opportunity for character study, and Grant Naylor clearly understood that. Time travel was used, in some way or another, in: Future Echoes, Stasis Leak, Backwards, Timeslides, White Hole, The Inquisitor, Out of Time, Tikka to Ride, Ouroboros, Pete, Part 1, and Pete, Part 2.
Rimmer, later on in the episode must confront his own self as well, and comes to the conclusion that in some respects his own life has been a failure. Thus, time travel here is used not so much as a way to display Grant Naylor’s cunning ability to get around the causality difficulties that arise from the concept, but it is used as a means for character study. It is not used as a science fiction concept – in what’s known as “hard SF,” which is SF that does not offend any natural laws that we currently know of and acts within the boundaries of science, the concept normally drives the plot. In “soft SF,” which tends to focus on character study or use of the “softer” sciences, such as psychology, the characters generally drive the plot.
In most time travel stories, it is the era that the characters go to that drives the plot – time travel, in the case of Timeslides, is both a character study and plot-driven. It’s certainly soft SF, since there is no logical explanation for any of the scientific phenomena taking place. Some writers tend to create an either/or situation in their stories – it’s either character study with little plot, or it’s a plot-driven story that pays little attention to characters. It takes a certain amount of talent to make a story both, and while it’s certainly not uncommon for stories to be both, Grant Naylor shows they have enough talent to pull it off.
1. Stephen Hawking, “The Future of the Universe”; publication date unknown.
2. Damon Knight, Creating Short Fiction. St. Martin’s Press, 1997.
3. The Official Red Dwarf Website – Series III Production