by Conroy
The latest time travel entertainment
In a couple of weeks Fox will air Terra Nova, the most expensive television program in history. The show's premise is that future civilization can only be saved by sending humans back 85 million years into the past. I have no idea what in this extinct period is going to save humanity (I'm assuming that will be the ultimate outcome of the show), but such a setting does allow for dinosaurs (plentiful in the trailer) and undoubtedly many other obstacles challenging to modern man. Whatever the details, the program is just the latest in an unbroken string of high profile television shows, movies, and literature based on time travel. Or what I like to call the tired time travel conceit. Tired and preposterous. (It's right up there for me with all those movies where one person's consciousness gets switched into another person's body, or the unending end of the world apocalypse stories.)
The idea of time travel has been around for centuries (if not longer) and its use in fiction became prevalent in the nineteenth century, when the genre was adumbrated by Dickens in A Christmas Carol, then explicitly used by Mark Twain in A Connecticut Yankee in King Arthur's Court, and perhaps most famously in H.G. Wells' The Time Machine. And these are just the more noteworthy examples. In time, time travel has become even more popular, unfortunately.
Now don't get me wrong, I like science fiction. And I know the whole point of the genre is to take humans to places and times different from the here and now. After all, isn't the point to remove people from the familiar and surround characters with radically different conditions in order see with fresh eyes the realities of the human condition? Or at least pose the relevant questions in a different light? That's the core of science fiction and it makes for some great stories and ideas...but time travel? Really, come on.
Time Travel and Paradoxes
The Terminator sent from the future
One well known example of what drives me crazy about time travel stories is from the Terminator. In the story a war between humans and machines is being fought in the not-too-distant future. The machines utilize time travel to send back an android (excuse me, "cybernetic organism") "terminator" to kill Sarah Connor, the mother of John Connor the human leader, before he was conceived. If the android succeeds then Connor will never be born and the human rebels will be leaderless (I guess). To stop the Terminator, Connor sends back a human to protect his young mother. In the process of the movie, the human protector, Kyle Reese, impregnates Connor's mother -- with Connor. This is a classic example of what is known as a predestination paradox. Reese travels back in time on orders from John Connor, impregnates Connor's mother, who then gives birth to John Connor. If Reese is never sent back, Connor can never be born, and the adult Connor cannot order Reese to go back and protect his mother. There are other examples of this just from the Terminator and its sequels.
Michael J. Fox saving the future
Another common absurdity is what's known as the grandfather paradox. This is where someone goes into the past, affects history in someway (such as killing your grandfather before he met your grandmother) that invalidates the future, which would prevent the person from going into the past in the first place. Or in a more general sense, just affecting history in a way that alters the future from which the person came. This is exactly what happens in the Back to the Future movies. Like when Biff goes back in time to give his younger self the knowledge to win huge gambling fortunes on the outcomes of sporting events that he knows, thus changing the circumstances of his ancestors, those of Marty McFly's (Michael J. Fox) family, and the entire community of Hill Valley.
Another classic mistake is what's known as an ontological paradox. This is when an object or piece of information is presented in a time travel story but has no logical origin. For example, and sticking with Back to the Future, McFly plays the song "Johnny B. Goode" at the high school dance. In the audience is Chuck Berry, the writer of "Johnny B. Goode." Berry is then inspired by what he hears to (presumably) write the song. Hence the song has no logical origin. This is a clever trick that writers (and screenwriters) seem to like, but needless to say, it drives me nuts. The Terminator series does the same thing, with the technology that leads to the development of Skynet (the machine consciousness) coming from the disabled Terminator -- who was sent back by Skynet.
Once one of these paradoxes appears, and they almost always do, the story loses a lot of appeal. After all, are we the reader or viewer supposed to overlook a glaring impossibility in what is called science fiction? It's science fiction because it is presenting an alternate reality with verisimilitude, with plausible conditions. Without that it's just fantasy.
And this addresses only the idea of time travel not the method of how it would be accomplished. (See the footnote at the end for one glaring practical problem that always goes unsaid in time travel stories.)
A Little Bit of Science
Speaking of science, how does the concept of time travel stand up to our understanding of reality? Well in theory, faster-than-light travel, wormholes, and aspects of general relativity, seem to make time travel possible. But the weight of scientific thought and rudimentary experiments show that time travel is fantasy (maybe I shouldn't object to the paradoxes above then). In fact, the logical contortions that some scientists go through to try and justify the theoretical (never mind actual) validity of time travel makes it seem even more of a pipe dream. Parallel universes, negative energy, infinitely large time machines, are just a few examples suggesting science veering away from reality.
Perhaps the real question, the fundamental question, is the nature of time. Is time eternal, that is all of time exists not just this moment? If so, the idea of time travel holds some appeal. If all time is there somewhere then perhaps we can travel to it. The implications of Einstein's theories of relativity, notably the relativistic nature of when something happens, have pushed many scientists to believe that objects exist through time like they do through space. They may be right, but I don't think so.
The present author strongly believes in presentism, that is the only thing that actually exists is the present, the words you are reading...NOW...the past doesn't exist and neither does the future. The past happened and the future will happen, but they don't actually exist. Does time exist? Certainly, the universe is changing constantly and that change happens only one way, forward in time. I'll stand behind the Second Law of Thermodynamics (entropy) for the theory and our everyday common experience for the facts (the sad fact that we get older every day). In presentism, time travel is an absurdity. There's no time to travel to.
So What About Real Time Travel?
Rip Van Winkle a different kind of time traveler
That's not to say that I don't believe in a form of "time travel." It's just much more limited and mundane than the fanciful inventions seen in the movies and television. Go back to Washington Irving's story of Rip Van Winkle. A man wanders into the mountains, drinks a mysterious liquor and falls asleep. He awakens 20 years later to a world that has moved on. His wife is dead, his children are grown, and the town is changed. Hasn't he for all intents and purposes traveled to the future?
If someone wants to travel in time, albeit only forward in time, I would tell them to do like Tom Hanks' character in Cast Away and go to a desert island for five years. Without contact with the outside world time will stand still - at least for one person's interactions with the rest of civilization. At the end of five years the person would come back. The world will be different, not unrecognizable probably, but different. The person will have traveled five years into the future. The catch of course is that it takes five years and at the end he or she will know nothing more than anyone else. And who has the patience -- and time -- for that?
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So time travel is science fantasy at best. More likely it's pure fantasy. As a generic plot device to take people to a different time, I'll live with it, but as an active contrivance that drives a plot, I'll tune out. Time travel stories can be entertaining (the Terminator movies for example - at least the first two), but they're silly at the same time.
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Just One Practical Problem
The DeLorian time panel
So here's a practical conundrum with time machines that I've never seen addressed. Somehow the time machine is programed to go back to a certain point in time. Think of the DeLorian in Back to the Future. Okay, I guess somehow the machine can relate the human date (day/month/year) to some sort of universal time. Although that's my supposition and it requires us to have hyper-specific knowledge of exactly how old the universe is, at least to within 12 hours or so, which we're never likely to have. Anyway, the time machine goes back to that previous (or forward to a future) point in time. However, it's never told where to go in space. Earth, or any other destination, moves in space as it moves through time. Earth revolves around the sun, which revolves around the center of the galaxy, which moves within the universe. And since there's no way to say exactly where any place is in space relative to any fixed point (relativity says there is no fixed perspective), and since the universe is constantly expanding at a changing rate, that information can't be provided.
The upshot is that a time machine might arrive at the right point in time but would almost certainly arrive at the wrong point in space. Writers may wave this issue aside, they're gods of their worlds after all, but that doesn't solve the issue.
