3 The Ship of Theseus
Have you ever wondered why movies are so obsessed with clones? Sometimes it's the only technology that will let you tell the story you have in mind -- an evil corporation needs to farm spare body parts, or the Alien franchise needs to clone Ripley back to life. But other times, like with the clone armies of the Star Wars prequels or the Jurassic Park scientists going out of their way to say that they're cloning the dinosaurs, it's almost like blockbuster movies are just looking for an excuse to get the concept of cloning into the mix. In real life, clones are pretty boring. Cloned sheep are the same as regular sheep, and on its surface, even human cloning is only as interesting as identical twins.
Or the odd army of soulless clone warriors.
But clones are actually great at illustrating an ancient thought experiment called the ship of Theseus that movies have been using and reusing to blow minds for years now. It was first posed by Plutarch, an ancient Greek philosopher who asked his audience to imagine that the ship sailed by the Greek hero Theseus was repaired so much over the generations that eventually none of the original wood remained. Is that still the ship of Theseus?
If you're failing to see the implications of that question outside of the world of boat naming, consider this: Science has determined that our cells are shed and replaced approximately every decade. So when that happens, are you still the same you, or is that person dead, and you're the replacement? Keep in mind that 10 years ago you were masturbating with a totally different set of junk.
"It's like I don't even know you anymore."
Every movie about cloning is raising that same question in one way or another. Probably the most successful version of the question is in Christopher Nolan's The Prestige, in which Nikola Tesla builds a machine that spits out an exact double of whatever is inside of it and also teleports one of them across the room, like a Xerox/fax machine combo. A magician (Hugh Jackman) uses the machine to make it appear as though he's teleported across the room, but since there are now two of them, he's forced to drown the version of himself that started out in the machine. In the final scene of the movie, Jackman explains that each time he copies himself, he has no way of knowing if he's going to be the guy in the tank or the guy who pulled off the trick.
Luckily, his drowning fetish makes it a win-win endeavor.
The movie leaves us with the haunting question of which one is the original, or if there is an original. Is Jackman getting teleported every night with the double being some waste product, or is he essentially committing suicide and being reborn every night? The same question could be asked by every single member of George Lucas' clone army, and also by every Star Trek character who steps into the transporter.
After all, the transporter can't just move people from place to place. It would have to break apart their atoms and rebuild them elsewhere. So when Kirk uses the transporter, does that mean that the real Kirk is now dead and the new Kirk is just an imposter?
"Kirk to bridge. I've beamed into something younger ... sassier."
2 Quantum Immortality
Movie protagonists tend to be improbably lucky. No one wants to shell out money for a Die Hard movie just to see Bruce Willis get killed five minutes in. That'd be super boring. Action movies are about one thing: watching a guy beat the odds and kill a bunch of dudes without getting killed himself. James Bond has made it through 23 movies despite facing odds that seemed improbable at best.
"The disease is B. Hepatitis B."
And it's not just the superhuman action heroes. In the sequence in Back to the Future in which Marty McFly first travels back in time, he is staring down certain death from a machine-gun-wielding Libyan terrorist, and then he finds himself in the sights of a farmer with a shotgun (the farmer manages to miss him three times at close range). It's almost like movies are about a bunch of people whose superpowers are just extraordinarily good luck.
As it happens, there's a thought experiment in quantum physics called quantum suicide that might explain why every one of those movies is illustrating how reality actually works. The theory arose when scientists were poking around inside the atom and noticed that certain particles appeared to move in two different directions at the same moment.
"If you keep pulling, we'll turn into hydrogen! Is that what you want?"
To understand why that should be impossible, imagine that you balanced a perfectly sharpened pencil on a tip occupied by one of these particles that spins left and right at the same moment. If the particle actually did move in both directions, the pencil wouldn't know whether to tip left or right. Or more specifically, it should tip in both directions at the same time. Now obviously, if you actually balanced the pencil in this way, you'd see the pencil tip in one of the two directions, because that's how reality works. What science hasn't been able to figure out is how reality chooses which of the two directions to make the pencil tip. The most interesting theory they've come up with states that reality doesn't choose, and instead branches off into separate parallel universes.
Now imagine if, instead of a pencil balanced on one of these particles, there are 10 of these particles connected to a contraption that fires a gun at your head if they move right and lets you live if they move left. After the first test, reality branches into two parallel universes, one in which you're alive and another where you're dead. After the second test, you're dead in three universes, still alive in one. After 10 tests, there are 999 parallel universes where a bunch of scientists are cleaning your brain matter off the wall behind you, and one universe where you're still alive. According to the "many worlds" theory, the scientists have a 99.9 percent chance of existing in one of the realities where they're about to have a lot of explaining to do. But since you no longer exist in any of those realities, from your point of view, you have a 100 percent chance of existing in the one universe where the gun never fired. You are guaranteed to continue living in one of the 1,000 universes that you just created, which is, of course, the one that you're going to be aware of.
In 999 universes, McClane was gunned down while picking glass out of his feet.
If you take the many worlds theory of quantum physics to its logical conclusion and apply it to the thousands of tiny particles bouncing around in the human brain, and in every object you encounter on a daily basis (or any gun that gets fired at you), you get what's known as quantum immortality. Basically, in any given situation in which it's theoretically conceivable that you survive, there is a timeline in which you actually survive. You're living in one of the infinite different versions of the world in which you survived. There are countless thousands of other universes in which you didn't survive, but you no longer exist in any of those. So the universe that you're aware of is one of an infinite number of universes in which you're just naturally, inexplicably luckier when it comes to not dying.
When we're watching an action movie, we might think that we're watching a protagonist slaloming through a bunch of explosions to an improbable happy ending, but it's just as accurate to say that we're watching the theory of quantum immortality illustrated over and over again. If there's even the remotest probability that the gun will jam, that's what will happen in the universe that the protagonist perceives. According to the many worlds theory, an action hero is the perfect metaphor for how we experience the world around us: He gets in a car wreck and just happens to be thrown clear. Bullets fly all around him, but none hit. Aliens attack, and crazy old Randy Quaid flies his crop duster into the mother ship. There's a nuclear explosion, and he jumps into a handy refrigerator. Regardless of the dangerous situation, the action hero will always survive. And we love watching action movies because the action hero's version of reality is the closest the movies come to our own version of reality, in which we keep getting insanely, improbably lucky.
Somewhere, a version of you has won the lottery, and that asshole won't give you a dime.