It’s taken me a while to get this put together. I’ve read a lot about time travel and time travel theory, maybe too much, and I just couldn’t figure out what exactly I believe as far as time travel possibilities and what theories I buy into. But I read The Time Machine about a week ago and I need to write about it.

H. G. Wells tells the story of an eccentric man who has his friends over for dinner to show them his time machine. He explains that he has come to understand that we can move through 3 dimensions of space, length, breadth, and height. There is a 4th dimension that we have hitherto had control over, that being time. We all move through time at the same rate. But this Time Traveler has built a machine that can travel through time, forwards or backwards.

The next time his friends are over for dinner, he recounts to them his travels through time into the 800,000-year-distant future. He tells them how the landscape changes, how the weather and environment change, and how society has changed.He recounts tales of the Eloi and the Morlocks, two divergent races of futuristic man, formed by hundreds of thousands of years of societal shaping.

Instead of reviewing the book and the story (there’s just too much good stuff in there!), I include here my musings about time travel. You see, last year I took a college course on Spanish Science Fiction, and we spent a good few weeks on time travel alone, discussing theories and ideas. I have some ideas set, but they mostly refer to time travel into the past…

The Novikov Self-consistency Principle is a theory that if you travel into the past, and try to change something in the present (which in the past, is the future), that your actions will reverberate in that present. It sounds a bit complicated, but let me use a reference that’s a bit more familiar. Harry Potter‘s use of time travel with the time turners follows the NSP. In The Prisoner of Azkaban, Harry gets hit in the head with a snail shell (this happens in the present). Then, when Harry goes back in time, he throws a snail shell at his own head to get his attention. The same principle applies when Harry is saved by his dead father’s patronus, only to later realize (after traveling back in time) that it was his own patronus. Harry’s actions during time travel made up an essential part of the present. He just didn’t know it yet.
This theory, which I subscribe to, makes it impossible to change the present by traveling into the past and trying to change points of history.

But The Time Machine isn’t about traveling into the past; it’s about traveling into the future. So I got to wondering: How would the Novikov Self-consistency Principle apply to time travel into the future? If everything happening in the present is consistent with what has happened in the past, wouldn’t everything in the future need to be consistent with everything happening in the present and the past?

Here’s my theory: Based on the implications of the NSP, the present is unalterable to a time traveler who has left the present and traveled into the past. The same is also true for a time traveler who has gone into the future; he cannot alter the present. One in the present cannot alter the future either. The present is the only alterable timeline.
I see the timeline like a string being glued down to a table. That which has been witnessed already as some form of the present, has been glued down. The entire past is glued down to the table, because it has all been witnessed. The present is currently being pressed onto the table, and the string can be twisted or turned this way or that in order to alter the path that the string will lead to. The present is the point at which the string may be pulled to the left or right.
The future has yet to happen, and is therefore alterable, one would suppose. However, the moment that a time traveler experiences the future, he will then remember it as a piece of his past, an experience that has been glued to the table. Once glued to the table, this point in the future becomes unavoidable. Even if you try to stretch the string one direction, it will inevitably bend back the other direction in order to meet the future (that at one point became a part of the past.

This doesn’t really account for religious visions of the future, like Scrooge seeing his own dark future, and then changing the present to avoid it. This is the theory I have for those who have physically travelled into the future.

In any case, H. G. Wells did it again. I heartily recommend The Time Machine and any other novel about time travel, really.