Why Doc Brown Should Secretly Destroy the DeLorean
by Jimmy Alfonso Licon
If I could turn back time
If I could find a way
I’d take back those words that have hurt you
And you’d stay— Cher
Introduction
The astonishing popularity of the Back to the Future franchise is likely explained partially by the involvement of time travel—an endlessly fascinating topic to people from various walks of life. Who doesn’t want to travel back in time to change the past for the better? Though there is no doubt about the imagined upsides of time travel, there are major downsides too. Imagine that someone traveled into the past to change the outcome of World War 2. The results could be catastrophic as Marty McFly discovered this when he nearly erased himself and his siblings from time by unwittingly interfering with the romance between his would-be parents.
The dangers and pitfalls of changing the past are recognized by Doc Brown in Back to the Future Part II upon discovering that Marty and Doc Browns’ timeline was altered for the worse (e.g., George McFly is murdered) by Biff using the time machine to change the past for his own gain. This event forced Doc Brown to realize that ‘time travel can be misused and why the time machine must be destroyed.’
The aim here is to explain why Doc Brown is right, even more than he knows. Luckily, though changing the past is possible in the fictional world of Back to the Future, it is logically impossible in the real world due to a temporal paradox[1] colloquially known as the grandfather paradox. That is the focus of the next section.
What is the Grandfather Paradox?
The grandfather paradox is an obstacle to anyone traveling back into the past to change it, even if they owned a fully operational time machine. Begin with a simple example. Suppose that Marty wants to kill his grandfather. He decides that his best chance to do so, undetected by other family members, would be to kill his grandfather in the past. After traveling back in time, Marty exits the time machine to find his teenage grandfather alone and vulnerable. Here we pause to ask a simple question: can Marty kill his grandfather? No. Despite the fact that Marty has a time machine, travelled back in time, and that his teenage grandfather is alone and susceptible to a sneak attack, Marty will fail. The explanation is what philosophers call the grandfather paradox. If Marty killed his grandfather, before he met Marty’s grandmother, then there never would have been an opportunity for his grandfather and grandmother to meet, fall in love, and have the children who would become Marty’s parents. In that scenario, Marty would never have existed, and so wouldn’t be able to kill anyone. As the philosopher, David Lewis, explains,
Tim cannot kill Grandfather. Grandfather lived, so to kill him would be to change the past. […] Either the events of 1921 timelessly do include Tim’s killing of Grandfather, or else they timelessly don’t. We may be tempted to speak of the “original” 1921 that lies in Tim’s personal past, many years before his birth, in which Grandfather lived; and of the “new” 1921 in which Tim now finds himself waiting in ambush to kill Grandfather. […] If Tim did not kill Grandfather in the “original” 1921, then if he does kill Grandfather in the “new” 1921, he must both kill and not kill Grandfather in 1921[2].
The point is that changing the past results in a contradiction, just like it would be contradictory to believe that it is raining and that it is not raining at the same time. Both claims cannot be true. Unfortunately for Marty, Doc Brown, and the unwitting residents of Hill Valley (under Biff’s reign), this same temporal logic doesn’t apply to the fictional world of Back to the Future, where changing the past looks possible. One such character, Biff, changes the past, to benefit himself, in Back to the Future Part II: once old Biff realizes that Doc Brown’s DeLorean is a time machine, he steals it and travels to the past with a copy of a sports almanac to help his younger self cheat at sports betting. Young Biff then uses the temporally displaced almanac to place winning bets on sporting events whose outcome he already knows.
In the actual world, old Biff would have been prevented from altering the past to his benefit by the logic of the grandfather paradox: older Biff travels back in time to give younger Biff a copy of a sports almanac from the future. Young Biff then places winning bets on sporting events using the almanac. As young Biff ages into older Biff, he realizes that he must travel back into the past to give young Biff a copy of the sport almanac without which young Biff wouldn’t know what sports team to bet on. Herein lies a dilemma: either young Biff lacks a copy of the sports almanac—thereby giving older Biff a reason to travel back into the past and to deliver it to his younger self – or he has a copy. On the first option, an explanation is lacking for how it is older Biff became rich using the sports almanac he doesn’t yet have. Either that, or, on the second option: young Biff already owns a copy of the temporally displaced sports almanac and used it to place bets that made older Biff rich. Here we still need to explain how younger Biff had a copy of the almanac before older Biff left the future to give it to him, because it originated from older Biff traveling back into the past from the future. Either option is results in temporal contradictions without hope of resolution.
As Biff altering the past and the sports almanac example illustrate: the ability to change the past could result in a temporal catastrophe. The next section elaborates.
A Temporal Can of Worms
In many ways, it is good that the grandfather paradox blocks us in the real world from changing the past. Why? Temporal change could easily be weaponized. The ability to radically alter the past would dwarf the destructive power of nuclear and biochemical weapons. Imagine that disgruntled Nazis, upon losing WWII, decided to build a time machine that would allow them to alter past events, especially the outcome of the war. Suppose that Ludwig traveled back in time—armed with information gained after the war—to warn the German high command of an invasion from the Allies such that the Germans could repel the attack, altering the outcome of the war. Such a machine would likely be the most powerful weapon known to humanity. There would be a strong temptation to use such a machine for evil.
Here it must be conceded that a time machine that allowed one to alter the past could be used for the good too. As an example, compare how George McFly and Biff interact at the start of Back to the Future, and their relationship at the end of the movie: at the start, Biff is George’s boss and regularly abuses, bullies, and takes advantage of him. George lacks the guts and courage to stand up for himself, and Biff lacks the fear and respect for George to treat him with dignity and decency; whereas, by the end of the movie, George is Biff’s boss, and that Biff treats the entire McFly family respectfully. This is an example where Marty altering the past improves the lives of the McFly family. It is accurate to say that the DeLorean has the power to change the past for the worse and for the better, and it could even be used to reverse bad changes to the past. If so, then, why should Doc Brown secretly destroy the DeLorean? We explain in the next section.
The Case for Destroying the DeLorean
If the DeLorean could be used to change the past, then it could be used to do so for the better or for the worse—in fact, both good and bad changes to the past happen in the first two Back to the Future movies. So, then, why does Doc Brown have a moral duty to secretly destroy the DeLorean. There are a couple reasons to dismantle it, despite the good that could be accomplished with it in the Back to the Future fictional universe.
The first reason is that doing good and doing bad are not morally equivalent. Consider that, like with medical doctors, we intuitively have a stronger moral duty to not harm others or make them worse off than we do to better their lives or benefit them. As moral philosophers, Gerald Harrison and Julian Tanner, explain,
[There is] an interesting asymmetry between preventing someone coming to harm, and benefiting someone. Intuitively, it is far more important to prevent causing and/or allowing harm to befall others than it is to positively benefit others[3].
Suppose that Doctor Jack only has time to perform one surgery despite two people needing an operation: Robert, who needs to have nasal passages expanded to make it easier to breathe, and Destiny, who is waiting on a facelift. Clearly, Doctor Jack has a stronger obligation to operate on Robert than to operate on Destiny for the simple reason that without surgery, Robert is likely to die of heart failure, a stroke, or something as bad. Intuitively, we have a greater moral duty to prevent causing or allowing harm to befall others, than we do to positively benefit others. And so, Jack has a stronger moral duty to Robert than he does to Destiny.
The same reasoning applies to the issue of what to do with the DeLorean: since it could just as easily be used to do good as to do evil, Doc Brown (and Marty, to a lesser degree) has a stronger moral duty to destroy the DeLorean such that it cannot be used to make people worse off than he does to allow it to exist to improve people’s lives. There are, of course, many avenues by which one could use the DeLorean to improve the lives of others, but allowing it to exist such that one could improve the lives of others by altering the past is to take a risk that someone could steal the DeLorean to do evil. So, because one could just as easily use the time machine to do good as they could to do evil, it follows from the asymmetry between the stronger duty to prevent causing harm and the weaker duty to positively benefit someone that one has a duty to destroy the DeLorean.
There is second reason that the DeLorean should be destroyed: even with the best of intentions, it is too easy to make a mistake that render the past (and the present and future) worse off than it would have otherwise been without intervention. To put the point differently: because one has a stronger duty to avoid causing or allowing harm to others than to positively benefit others, they should avoid interventions that are likely to cause harm to others, even when the intervention is done by someone with the best of intentions.
A scene from Star Trek: Voyager nicely illustrates this difficulty,
CHAKOTAY: Component 37329, a rogue comet. About eight months ago, Voyager made a course correction to avoid the comet. According to my calculations, it led to our entering Krenim space.
ANNORAX: The solution, then, would be to erase that comet from history.
CHAKOTAY: Exactly. Voyager would have stayed on its course and bypassed Krenim space altogether.
ANNORAX: Sounds simple enough. Conduct a simulation.
CHAKOTAY: Temporal incursion in progress. What happened?
ANNORAX: Had you actually eradicated that comet, all life within fifty light years would never have existed. Congratulations, you almost wiped out eight thousand civilizations.
CHAKOTAY: I didn’t consider the entire history of the comet.
ANNORAX: Four billion years ago, fragments from that comet impacted a planet. Hydrocarbons from those fragments gave rise to several species of plant life, which in turn sustained more complex organisms. Ultimately several space-faring civilizations evolved and colonized the entire sector.
CHAKOTAY: By erasing the comet I altered all evolution in this region.
ANNORAX: Past, present and future. They exist as one. They breathe together. You’re not the only person to make this mistake. When I first constructed this weapon ship, I turned it against our greatest enemy, the Rilnar. The result was miraculous. With the Rilnar gone from history, my people, in an instant, became powerful again. But there were problems. A rare disease broke out among our colonies. Within a year, fifty million were dead. I had failed to realize that the Rilnar had introduced a crucial antibody into the Krenim genome, and my weapon had eliminated that antibody as well.
CHAKOTAY: And you’ve been trying to undo that damage ever since. But each time you pull out a new thread, another one begins to unravel.
ANNORAX: You can’t imagine the burden of memory that I carry. Thousands of worlds, billions of lives, gone, brought back, gone again. I try to rationalize the loss. They’re not really being destroyed, because they never existed. Sometimes I can almost convince myself[4].
Clearly, Annorax has mixed intentions: restoring one’s people and culture looks like a noble goal, but not when at the expense of thousands of other civilizations. The point of the scene, though, is to illustrate that even with the best of intentions, changing the past for the better is a task too easy to get wrong. This is because the past is so interwoven with the present and the future through a complicated mix of causes and effects that is hard to predict and anticipate. This is partly because our knowledge of the world is socially distributed across individuals, communities, and events[5].
To illustrate just how socially interconnected our knowledge of the world is, consider a simple fact: you (as an individual) do not know how to make a peanut butter and jelly sandwich[6]. ‘Of course I do!’, you might object—but that objection misses the point. The claim here is not that one lacks the knowledge of how to assemble a sandwich comprised of bread, peanut butter, and jelly. Instead, the point is that in a more fundamental sense, you lack the knowledge needed to make the bread, peanut butter, and jelly. There are many ingredients needed to make the bread alone: one would need to know how to domesticate wheat, how to design and manufacture farm equipment to grow and harvest the wheat, and how to produce fertilizer. Just think about the many inputs required to produce the rubber that comprises the tires on the tractor needed to harvest wheat. And that is just some of the stuff one would need to know to make the bread, not to mention the other steps needed to produce the jelly and peanut butter. If something as simple as knowing how to make a peanut butter and jelly sandwich is too complicated for any single individual, then changing the past for the better would be an ever more challenging task that, even with good intentions, one could easily make worse. Doc Brown is clearly brilliant, but changing the past for the better is likely beyond even his abilities. There are thus good reasons to destroy the DeLorean before it can be used for evil. But why should Doc Brown do so secretly, and remove any evidence of its existence? That is the topic of our final section.
Why Doc Brown Must Secretly Destroy the DeLorean
We established a case for Doc Brown having a moral obligation to destroy the DeLorean to prevent it falling into the wrong hands. However, there still remains the issue of why Doc Brown has an obligation to go about it secretly. Simply destroying the DeLorean, without removing evidence that a time machine exists, would seemingly be sufficient for Doc Brown to discharge his moral duty not to inflict on, or facilitate others inflicting harm, on innocent individuals, right?
Not quite. The issue here is that if Doc Brown destroys the DeLorean, but the evidence of its time traveling abilities remains, then such evidence is what engineers call a proof-of-concept: a working prototype that demonstrates the validity of the underlying theory. One might draw up plans for a new combustion engine, for example, but only find investors once one has built a prototype to show that the plans work in the real world.
Indeed, the Hill Valley Mall scene—early in Back to the Future—is itself an example of a proof-of-concept. Even though, by Doc Brown’s own admission, he invented the flux capacitor—the key component for time travel—decades prior, he wasn’t able to build a test model (aka a proof-of-concept) until the mall scene. Here is the salient exchange between Doc Brown and Marty,
DOC: He’s [Einstein the dog] fine, and he’s completely unaware that anything happened. As far as he’s concerned the trip was instantaneous. That’s why Einstein’s watch is exactly one minute behind mine. He skipped over that minute to instantly arrive at this moment in time. Come here, I’ll show you how it works. First, you turn the time circuits on. This readout tell you where you’re going, this one tells you where you are, this one tells you where you were. You input the destination time on this keypad. Say, you wanna see the signing of the declaration of independence, or witness the birth or Christ. Here’s a red-letter date in the history of science, November 5, 1955. Yes, of course, November 5, 1955.
MARTY: What, I don’t get what happened.
DOC: That was the day I invented time travel. I remember it vividly. I was standing on the edge of my toilet hanging a clock, the porcelain was wet, I slipped, hit my head on the edge of the sink. And when I came to I had a revelation, a picture, a picture in my head, a picture of this. This is what makes time travel possible. The flux capacitor[7].
At this juncture, one may wonder why evidence of a proof-of-concept should be destroyed, e.g. destroying the video tape that Marty and Doc Brown made at the Hill Valley Mall. The reason is simple: proof-of-concept is something that would increase the confidence of those to invest and explore time travel technology due to the demonstration by Doc Brown and Marty. And a boost in confidence, by bad individuals, in the ability of technology to allow one to travel to the past to change it would increase the likelihood that someone would spend the time and money to invent a time machine of their own. Of course, this could happen anyway—it would be hard to control technological innovations. However, allowing the DeLorean to exist potentially enables would be temporal wrongdoers. So, Doc Brown is right (more than he knows) to conclude that due to the potential for abuse, the DeLorean should be destroyed.
[1] Jimmy Alfonso Licon (2015). The Time Shuffling Machine and Metaphysical Fatalism. Think 14 (41): 57-68.
[2] David Lewis (1976). Paradoxes of Time Travel. American Philosophical Quarterly 13 (2): 145-152, p. 148.
[3] Gerald Harrison and Julia Tanner (2011). Better Not to Have Children. Think 10 (27): 113-121, p. 18.
[4] Star Trek: Voyager (1997). Year of Hell, Parts I & II (Season 4, Episodes 8 and 9).
[5] Fredrich A. Hayek (1945). The Use of Knowledge in Society. The American Economic Review 35 (4): 519-530.
[6] Leonard E. Read (1964). I, Pencil. In Leonard E. Read (author), Anything That’s Peaceful: The Case for the Free Market. Foundation for Economic Education, pg. 136-143.
[7] Back to the Future (1985). Universal Pictures.
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Bio:
Jimmy Alfonso Licon is a philosophy professor at Arizona State University with research interests in ethics, AI, and political economy. He teaches classes like bioethics and philosophy of time, and wants his own time machine.
