92 10 CHANGING THE FUTURE: FATE AND THE TERMINATOR KRISTIE LYNN MILLER “The future is not set, there is no fate but what we make for ourselves.” —Kyle Reese, in a message to Sarah Connor “You’re dead already. It happens.” —Sarah Connor to her psychiatrist [Au: Throughout this volume the robot characters are referred to sometimes as "he" and "him" and other times as "it" (and occasionally "she"). In the copyediting, we have made few changes in this area, but as you read through your chapter, please give further thought to this issue, keeping in mind that, depending on the context, the Terminator and his/its fellow robots could correctly be referred to as "he" in one place and "it" in another. Please make any appropriate changes before you return this chapter to your editor.] While Terminator 2: Judgment Day is in many ways an uplifting story of hope, it is in lots of ways philosophically perplexing. There are two contrary sentiments in the story encapsulated by the quotes above. Kyle Reese tells Sarah Connor that the future is not set and can be what we make of it. The message is clearly intended to suggest that Judgment Day, the day when Skynet launches nuclear weapons against the human population killing three billion humans, is not inevitable. The other sentiment, expressed by Sarah to her psychiatrist while she is in custody, is that everyone around her is already dead, because Judgment Day will happen. She has knowledge of what will happen on August 29, 1997— Judgment Day—because she has been told what has happened in 1997 by Reese, who hails from 2029. For her, the future is fixed: the events of Judgment Day are inevitable. From a philosopher’s perspective, T2 raises all sorts of questions about the nature of the future and our ability to shape it. Which of these two sentiments is right? Can both be right? Let’s start with Sarah Connor’s statement to her psychiatrist that he is already dead because Judgment Day will happen. This is a 93 sentiment she expresses frequently, and with this in mind, it’s clear that she sees her job as keeping John alive so that he can lead the human resistance after the inevitable event. The Undiscovered Country: Does the Future Exist? There are lots of reasons to think that Sarah is right that the future cannot be changed. Sarah originally learned about Judgment Day from Kyle Reese, a time traveler from 2029. From the perspective of Reese, Judgment Day is an objective fact—it has already happened in his past. Sarah probably has the view, shared by almost all philosophers who’ve considered the nature of time, that it’s not possible to change events that have happened in the past.1 For instance, if Julius Caesar was assassinated in 44 BCE, then for us considering that fact today, it is not possible to change it. Yet many philosophers think that time travel is at least logically possible: they think that there is nothing logically inconsistent in the idea of time travel, even if they also think that time travel is not even close to being technologically possible.2 So while it would not be contradictory to suppose that someone could travel back to ancient Rome, if Caesar was assassinated in the past, then there is nothing a time traveler could do in the past to alter that fact. Whatever the time traveler does in the past, he must already have done in the past, so he simply becomes part of the story of how Caesar was assassinated. Let’s assume, then, that it’s not possible to change the past. If Judgment Day is a past event (at least relative to the time travelers from 2029), then that event can’t be changed, anymore than the event of Caesar’s assassination on the Ides of March can be changed. To put it another way, if it is true in 2029 that Judgment Day happened in 1997, then it must be true in 1994 that Judgment Day will happen in 1997. Given this, it seems right for Sarah Connor to believe that events will unfold precisely as she was told over the next three years. So the future must be fixed, its circumstances unavoidable. Many philosophers also think that the future is fixed because the future is as real as the present. And the events of Terminator and T2 seem to make sense only if we share that assumption. After all, if a T- 101 can travel back in time from 2029, then it seems as though 2029 has to exist for it to be from the time of the Terminator’s departure. Think about travel through space: if someone goes from A to B, it seems a safe assumption that both A and B exist, even if A does not exist exactly where B does. If A is here, then B is there, some spatial distance away.3 94 According to one very common view in both physics and philosophy, the same is true for “locations” in time. Philosophers call this view eternalism: other times are real, just like other places. But just as spatial location A exists somewhere other than where spatial location B exists, so too temporal location T exists somewhen other than where temporal location T1 exists. The past and the future exist, say eternalists, but they do not exist now. Eternalists often say that in their view, the world is a big four-dimensional block composed of every point in time and space (or space-time) from the beginning of the universe all the way to its end.4 If we suppose that eternalism is true, many of the events of T2 make good sense. The Terminators can travel from 2029 because 2029 is a perfectly real location in space-time: it exists, but it is not located in 1994. Eternalism is a very common view in philosophy, because it is supported by a lot of research in physics, in particular by Einstein’s theory of special relativity. Einstein tells us that depending on how fast you are moving, different sets of events will appear to be simultaneous. Suppose that the moment when the T-101 and the T-1000 arrive in 1994 (call it “T-moment”) is the present. T-moment and everything that occurs at that moment, exists. Now introduce a new character into the story: the T-2000, a Terminator that is capable of moving so quickly that he approaches the speed of light. The T-2000 is simultaneous with Sarah at T-moment, so given that Sarah exists at T-moment, so does the T- 2000. But this Terminator is moving extremely fast relative to Sarah. Special relativity tells us that the T-2000 will be simultaneous not just with Sarah, but with events that Sarah understands as both in her future and in her past. Some of these events occur in 2029, during the resistance. But if the T-2000 exists, and for this Terminator the events of 2029 are objective facts, then Sarah should think that those events exist too, despite their being in her personal future. So she should think that 2029 exists. What special relativity tells me is that for any event in my past or future, anyone who might be moving relative to me will see that event as simultaneous with my continued existence. But because their speed allows them to coexist with other events, past and future, this means I should think that all of the events in my past and my future are as real as the events I experience as being in my present.5 Not everyone accepts eternalism, though. Some think that something important distinguishes events in the future, the present, and the past. This idea hinges on the commonsense beliefs that the past is already written and unchangeable; that the present is alive and vibrant and especially real; and that the future is unwritten and full of possibility. Some philosophers think these differences in how we perceive time mark a real difference in the metaphysical nature of our universe. There are, roughly speaking, three different models that take seriously the idea that there is something metaphysically different about 95 present, past, and future.6 On one of these, only the present and the past exist, but as time moves on, what is now present becomes past. The space-time universe “grows” as new moments in time get added on to the end of the universe. This is known as the growing-block model of the universe.7 Like eternalists, philosophers who accept the growing-block model think the universe is a four-dimensional block, but they believe it includes only locations in the past and the present. So the present moment is the moment at the “growing” end of the block. In the Terminator timeline, when 1994 is the present, Sarah and John Connor exist. So does Caesar (44 BCE) and the T-101 (1984), but the artificially intelligent machines of 2029 do not yet exist; or at least, this is what the growing-block model tells us. Living in the Now: Is This All There Is? There is an alternative to eternalism and the growing-block universe that also takes seriously the idea that there is something very different about past, present, and future. This is “presentism,” the view that only the present exists.8 For the presentist, the totality of reality is a thin sliver of space-time that is a single instant of time.