The Philosopher's Cornered
by Dan Wolaver
In one Star Trek episode, Capt. Kirk answers another ship's
distress call, only to find his ship trapped in a magnetic storm and
sent back a day in time. He sends out a distress signal, and then
realizes that his is the distress call he originally responded to.
My mind started to reel, trying to make sense of it all. The answer is, of course, that time travel is impossible, so it's all nonsense. But mankind would like time travel to be possible, and the past seems so real to the mind. If we can travel in the dimensions of space, why not in the dimension of time?
From the standpoint of physics, we only have the present, and the past is what we can infer from the present state of things. If you enter a room, sit in a wooden chair, and notice that the seat is warm, you're pretty sure that someone vacated that chair sometime within the last minute. But if the person left the seat half an hour ago, it would take a very sensitive instrument to detect any residual elevation above room temperature. You would probably have to resort to longer-term evidence, such as the memory of someone who has been in the room. As the evidence becomes fuzzier, you become less sure of the past. I contend that if there is absolutely no evidence in the present of what happened at some point in the past, it's meaningless to ask, "What really happened?" The mind rebels at this claim. "Something must have happened; it was real then and it's real now. God knows what happened!" But in a practical sense, if the past has left no record—no effect—on the present, it makes no difference what happened. More than that, there is no "happened."
Of course, I'm making up this situation, assuring that there is absolutely no evidence of the past. In practice we can almost* always find, with enough diligence, some record from which we can infer the past with some degree of confidence. But there's no such thing as a definite past; it's somewhere between nonexistent and "pretty darn sure." And if there's no definite past, there's nothing we can go back to.
The only thing that exists is the present and guesses as to how we got here. I don't object to referring to the past. It's a useful concept, but it's not as clear-cut as we would like to think. I do object to the idea of time travel. Give it up—it's not possible.
There's another advantage to realizing that the past exists only in the present record. Sometimes past actions weigh on us—something we did or someone else did that should have been done differently. We wish we could change the past because it continues to hobble us in the present. We play it over and over in our mind, ruminating and keeping it a present reality. But today is the reality, and yesterday is only a dream.** If we let go of the past—move on—in a very real sense that past is no longer part of us. And if others haven't moved on, that's their problem!
And that's my philosophy.
* According to astrophysicists, anything that happened before the Big Bang would have no effect on our universe, so there's no sense in talking about a "before."
** from an ancient poem Salutation of the Dawn