The Nowhere Argument
Do the past and future exist? Or does only the present exist? Metaphysicians divide on the issue. Eternalists believe that the past, present, and future all exist; i.e., some nonpresent things and times exist. Presentists believe that only the present exists; i.e., only present things and times exist. Someone who advances The Nowhere Argument against the possibility of time travel must be squarely in the presentist’s camp. The argument is essentially that, if presentism is true, then it is impossible to time travel, as you would be trying to get to somewhere that does not exist. This is a common concern about time travel. You may have been perplexed by something like this concern the first time you ever considered the possibility of time travel.
Rejecting Presentism (Challenging Premise 2)
There is one straightforward way of defeating the argument. We could reject presentism. How is it correct to say that the past and future don’t exist? Much of common sense would suggest that they do exist. For example, one seems to have no trouble saying that Elvis is the king or that Nixon is the only president of the 20th century to resign. These don’t seem troublesome, and they might even strike you as true, and yet Elvis isn’t alive now to be king, nor does Nixon exist now. Why do we talk so readily about the past and future using the present tense if, according to presentism, they don’t exist? Even our use of the past tense makes some trouble for the presentist. The presentist will have to explain how a past-tense sentence like ‘Abe Lincoln wore a stovepipe hat’ can be true if the name ‘Abe Lincoln’ does not refer to Abe. Presentism is also at odds with the theory of relativity insofar as it presupposes frame-independent or absolute relation of simultaneity holding among present events.
The Passage of Time (Challenging Premise 3)
There may be another problem with The Nowhere Argument, one pointed out by Keller and Nelson (2001), and also by Dowe (2005). The Nowhere Argument cannot be a good argument, because, if it were, it would also rule out the ordinary passage of time.
If The Nowhere Argument were a sound argument, then it would be true that no one ever survives even one nanosecond into the future, yet you just did this a few trillion times as you read this sentence. There are other more interesting cases of time travel that raise basically the same trouble. For example, astronauts on a space shuttle orbit the Earth at several thousand miles per hour for days on end. In this time, they not only survive the lapse of time, they also gain fractions of a second of time on their families back on earth. (See Relativity and Time Travel for more detailed discussion of this manner of temporal phenomenon.) The astronauts are actually slightly younger than they would otherwise have been; they have time traveled a fraction of a second into the future. It would be surprising if presentism ruled out this kind of time travel. We should suspect that there is something wrong with The Nowhere Argument besides its commitment to presentism.
Keller and Nelson conclude, on the basis of similar considerations, that “One way or the other, the presentist has to make room for travel to nonexistent times” (p. 335). So, prima facie, they seem prepared to deny Premise 3 of The Nowhere Argument as this argument is displayed at the top of this page. More can be said to make the denial of this premise plausible. Suppose you are a big fan of amusement parks and hear that they are planning to build a new one in Argentina. It doesn’t exist yet, but you are so excited that you start now to hitchhike your way there from Raleigh, NC. It seems that you are traveling to the amusement park even though it doesn’t exist (cf. Dowe 2005, pp. 443-444). What seems important is not that the destination exist when you start to travel, but that it exist when you arrive. Maybe we can travel to places and times that don’t exist.
What Time Travel Really Amounts To (Challenging Premise 1)
Before leaving The Nowhere Argument, it will help to consider a similar argument. Here it is:
- If someone is a historian, then s/he studies the past.
- The past and the future don’t exist.
- No one studies what doesn’t exist.
- No one is a historian.
From a very literal and logical way of thinking, it can seem strange that anybody studies something that doesn’t exist. How would anyone do anything to or even stand in any relation to something that doesn’t exist? Someone’s studying something or bearing any relation to it seems to require that the object of study has some reality. You can’t kiss the Jolly Green Giant! You can’t stand next to Superman! You can’t examine Atlantis! So, Premise 3 seems pretty strong. Premise 1, however, seems vulnerable; one could argue that, strictly speaking, historians do not study the past, but rather study artifacts or other remnants, objects that did exist and that still exist. Maybe doing history isn’t really studying the past.
What does this say about The Nowhere Argument? One could argue analogously that time travel doesn’t literally require traveling to the past or the future; they don’t exist and so we can’t stand in a relation to either one. Rather, when we time travel, we are engaging in a behavior or are in some state that already did or else will result in our arriving. On this way of looking at The Nowhere Argument, Premise 3 seems fine and Premise 1 seems false. Take our astronaut time traveler. Strictly speaking, maybe he is not traveling to the future. Yet he is time traveling. He is moving very, very fast and will as a result arrive having experienced less time than a friend did on Earth. That’s time traveling, even if, strictly speaking, it’s not traveling to the future or the past. This is the difference between saying that the time traveler in H.G. Wells’ The Time Machine is, say, traveling to the past and saying that he is sitting in a chair and pulling a lever, and thereby did arrive at times that did exist.
References and Further Reading
Dowe, Phil. “The Case for Time Travel.” Philosophy 75 (2005): 441-451.
Keller, Simon, and Michael Nelson. “Presentists Should Believe in Time Travel.” Australasian Journal of Philosophy 79 (2001): 333-345.
Markosian, Ned. “Time” The Stanford Encyclopedia of Philosophy (Winter 2002 Edition), Edward N. Zalta (ed.).