# Flashback: The Infinite Worlds of Bioshock Infinite

Years passed, I wrote my own sci-fi book with parallel universes and how to jump between them, but always wanted to write about Bioshock Infinite’s Many Worlds Interpretation. I’ve been just lazy. Three years later it is ready. And I hope you won’t be super bored. Because it’s rather scientific, more than interpreting how many parallel universes Elizabeth and Booker visited.

*“Most of the time they’re dull as dishwasher: a different colored towel, or tea instead of coffee. But sometimes? Sometimes I see something amazing” – Elizabeth*

Let’s summarize the story: there is a guy who looked for redemption through a baptism. He became a popular leader and called himself Father Comstock. He met physicist Rosalind Lutece, who found out how to travel between parallel universes in space and time. After lot of travels he became a 38 year old in a body of old man. He couldn’t have children anymore so used a tunnel in time-space to take a child from a parallel version of himself, Booker DeWitt. Some years later Booker took on a job to take a child back from the religious freak. Booker realizes Elizabeth is his daughter Anna, who he sold years ago. He jumps with her through time and space and lot of things are happening. Shortest summary ever, right? But it won’t be text just about the game.

Warning! Science starts here!

**Classic VS Quantum**

In classical Newtonian mechanics, everything is simple. If you have an approximate knowledge of the initial conditions and you know the laws of nature, you can roughly calculate the behaviour of the system (Predict the future! Yay!). But the microscopic world of tiny particles is governed by its own, different laws. One of these laws, the Heisenberg uncertainty principle, states that we can’t know both the position and momentum of a particle. Measuring the exact location of a particle causes the momentum to become uncertain and vice versa.

Let’s make an experiment. If Booker shoots and reproduce this with the same initial conditions, every time the result will be exactly the same. Bullet will fly the same way. That’s classical mechanics. But if you will make an experiment in the quantum world, let’s say track trajectory not of a bullet but an electron, results will be different. Because identical conditions don’t produce identical results here.

**The cat (or Lady Comstock)**

Heads or tails. Cat dead or alive. It always has 50% chance to survive and always 50% chance to die.

*Booker: But what is she? Alive or dead?
Robert Lutece: Why do you ask “what?”
Rosalind Lutece: When the delicious question is “when?”
Robert Lutece: The only difference between past and present…
Rosalind Lutece: …is semantics.
Robert Lutece: Lives, lived, will live.
Rosalind Lutece: Dies, died, will die.
Robert Lutece: If we could perceive time as it truly was…
Rosalind Lutece: What reason would grammar professors have to get out of bed?
Robert Lutece: Like us all, Lady Comstock exists across time…
Rosalind Lutece: She is both alive and dead.
Robert Lutece: She perceives being both.
Rosalind Lutece: She finds this condition…disagreeable.
Robert Lutece: Perception without comprehension…
Rosalind Lutece: …Is a dangerous combination.*

In quantum mechanics each particle behaves like a wave. Let’s explain this with our kitty. The wave: ψ (in Greek: psi) symbolizes the probability of cat’s behavior. When a cat is closed in a box, all amplitudes occur simultaneously (the cat is alive and dead and particle is in all places the same time. Insane, isn’t it?). It is in the **superposition** is the sum of these two states. **The wave function contains information on all possible ways the behavior of the particle. **

Function ψ_{z} of a cat describes two states: alive (ψ_{x}) and dead (ψ_{y}), but ψ_{z} of electron (rally tiny particle) contains a list of all the position in space and time (much more than two. Electron exists at all of its possible positions in space and time). When we open a box and observe (measure) the content we make a reduction of quantum states and we get only one outcome – the cat is alive (ψ_{x}) or dead is cat (ψ_{y}). **What we will see is a matter of chance**.

*(Cat wave function: when peaks of wave function superpose, the probability increases. When peaks meet wave trough, the probability cancel.)*

So called “Copenhagen interpretation” means that the act of observation causes the **collapse** of the wave function and we receive the only one state, because physically, only one outcome is possible. Niels Bohr, author of this interpretation, believed that quantum world can be experienced **only** through the medium of an experiment: when the radioactive decay of the atom is making interaction with a Geiger counter. As a result we have ticking, needle indicates a value on the scale etc. Invisible quantum event corresponds to an event in our world of classical physics.

**Ladies and gentleman, Hugh Everett III – the man who gave us many worlds!**

*“Every quantum transition taking place on every star, in every galaxy, in every remote corner of the universe is splitting our local world on earth into myriads of copies of itself. Here is schizophrenia with a vengeance.” – Hugh Everett*

In the 50’s of XX century Hugh Everett wrote PhD where was not impressed by Copenhagen interpretation which required an outside observer. Everett wanted to keep the process of measurement within the system. He wondered what would happen if the observer and the observed object are bound at the microscopic level, and at which point the wave function is reduced to a small part of the whole system? Do reduction occurs when the needle of Geiger counter records an events? But if the needle is not in a superposition until observer’s look at it? And what about the eye of the observer? What if the room enters another person? Is the wave function of the observer who looks at the Geiger counter makes collapse when other person in the room looks at him? So many questions!

Over a glass of sherry he wondered, what if the wave function does not collapse? What if the superposition of states **remain forever**? He characterized the physical condition of the entire universe not in classical terms, but as a universal wave function. This function describes all possible superpositions of classical states that develop continuously in a linear manner. In this way he got rid of the problematic process of measuring and monitoring. Finally Everett’s PhD was published as „Relative State Formulation of Quantum Mechanics” in 1957. Nobody was super excited about that.

*(Everett theory says that elements of superposition (all the “branches” of the tree of choices) are “real”. None of them are more “real” than the rest.)*

Decade later, physicist Bryce DeWitt (oh we know that name, don’t we?) took care of forgotten theory. He introduced the term “many worlds” for a first time. Together with his student Neil Graham, they published original, long thesis (John Wheeler, Everett’s promoter shortened text by three quarters) and finally theory was published as „The Many–Worlds interpretation of Quantum Mechanics” (Princeton, 1973).

DeWitt initially was very skeptical about the thesis, but eventually he became biggest supporter:

*“First, I was tickled to death that someone at long last, after so many years and so many tiresome articles, had something new and refreshing to say about the interpretation of quantum mechanics. Second, I was deeply shocked. I was so shocked that I sat down and wrote what turned out to be an eleven pages letter to Everett, alternately praising and damning him. My damning largely consisted of quoting from Heisenberg regarding the “transition from the possible to the actual” and insisting upon the fact that “I do not feel myself split.”” – Bryce DeWitt*

**I don’t feel myself split!**

DeWitt’s interpretation with branching worlds is the most popular understanding of Everett theory nowadays.

*„The idea of 10 ^{100+} slightly imperfect copies of oneself all constantly splitting into further copies, which ultimately become unrecognizable, is not east to reconcile with common sense. Here is schizophrenia with a vengeance… Here we must surely protest. We do not split in two, let alone into 10^{100+}” – *

*Bryce DeWitt*

The problem with the theory of universal wave function lies in the fact that in the original version, it requires an **infinite** number of universes, each of which splits into an **infinite number of versions of reality** when quantum choice is made and move forward every possible way at the same time. Guess how many parallel universes Booker DeWitt created during game? Remember, every choice creates parallel universe.

In game we see three Booker DeWitt versions: a soldier that wasn’t baptized after Battle of Wounded Knee (False Shepherd), a soldier that was baptized (Zachary Comstock) and Booker, the Martyr of the Revolution (on the posters in one of universes). There are more of them for sure, there is even one who never gave his daughter to Comstock. Why? Because when he decided to gave Anna, another branch was created with an universe where he’s daughter is with him. Do you wonder how and why Rosalind Lutece has quantum brother Robert? During the pregnancy of their mother, in about 9 week when sex of baby is developed, the universe split in two. In one of them Rosalind was born, in the other, Robert. It’s not everything, there are words where they don’t exist, are twins in one world, girls, boys, etc.

In the modern version of the theory of multiple worlds (by David Deutsch) we are not dealing with branching universes, but all possibilities exist simultaneously – there are an **infinite** number of universes that “start” as identical copies.

***

*“There are a million, million worlds. All different and all similar. Constants and Variables. There’s always a lighthouse. There’s always a man, there’s always a city… I can see them through the doors. You, me. Columbia. Songbird. But sometimes, something’s different… yet the same.” – Elizabeth*

Congrats, you read it! There’s another version of you who gave up in the middle or never started. Now think a bit about this: is it really possible to make Comstock never happen? Does ending makes sense? I’m saying nope, but won’t say why. Yet.

I’m sure now you want to know if it’s possible to travel across the universes. I have a surprise for you: it is possible! Physics is just wonderful, it allows you to do many crazy things, but the thing is that some of them are extremely unlikely. Scientists made a lot of research about opening tears (in our universe physicist are calling them Einstein-Rosen bridges or wormholes), would you like to read about it?