Is Anything Real? Three Existential Theories to Keep You Up at Night

The idea that human perception of reality may not be the truth is not exclusive to recent generations of scientists and philosophers. In fact, thought experiments centered around this concept can be traced all the way back to the Allegory of the Cave found in Plato’s book The Republic written in 300 BCE.

The allegory begins with prisoners that have spent their entire lives inside of a dark cave, they have chains on their legs so that they cannot move and chains on their necks so that they may only look at what is in front of them. Behind the prisoners is a fire and between this fire and the prisoners are people carrying puppets. These puppets cast shadows on the wall of the cave in front of the prisoners. To the prisoners, the shadows are reality as it is all they have ever known. Plato then suggests that one of the prisoners could become free and when this happens, he sees the fire and people. He realizes that the shadows are fake. The newly freed prisoner could then escape the cave and venture into the world outside. Blinking in the sunlight for the first time, the prisoner sees a world he was previously unaware of. Returning to the cave with plans to free his fellow prisoners, he finds that he can no longer see within the cave and, as such, can no longer see the shadows on the cave wall. He tells the other prisoners that what they are seeing is not real, but they do not believe him. Once they find out that he can no longer see within the cave, they believe he has gone blind as punishment for escaping [1].

This is a simple thought experiment that explores not only the limitations of human perception but also human resistance to new ideas that question what we believe to be true. We will explore this concept in depth as we examine three theories surrounding reality that are guaranteed to keep you up at night.

THEORY ONE: THE HOLOGRAPHIC UNIVERSE THEORY

What if everything we see is nothing more than a projection of an unseen universal plane?

The holographic universe principle states that everything we see going on around us in three dimensions is actually just a projection of information that exists in the two-dimensional plane that is the universe. This theory is based on results from the 1972 Freedman–Clauser experiment that discovered what is now known as ‘quantum entanglement’. This is the idea that subatomic particles like electrons – or, in this case, qubits – can instantaneously communicate with one another regardless of the distance between them [2].

Before going any further, let's explore what a qubit is. Think of a computer or your phone, digital devices like this run on what are called bits, which are the smallest units of digital information. These bits can exist in one of two states, like on or off on a light switch. The state is represented by a 1 or a 0.

Now, in the quantum world, we think in terms of qubits, which are the smallest units of quantum information. It is essentially, the quantum version of a computer bit. However, while bits can only exist as a 1 or 0 (like on/off), qubits can exist as either as a 1 or 0 or as all possible states between 0 and 1. Meaning, that a qubit has infinitely possible states instead of two. Further, qubits can become entangled so that the states of the particle become correlated so that a change in one particle can affect the other [3].

So, how do qubits relate to a two-dimensional plane?

According to this theory, if the universe is composed of information, then our universe is composed of qubits. Since qubits are flat, if we increase the number of qubits that make up the universe then – instead of increasing in volume – the universe increases in surface area. This is what makes up the two-dimensional plane of the universe as described in this theory. The qubits on this universal plane then alternate between entanglement and disentanglement, resulting in fields of entropy in constant states of change.

To summarize, the three-dimensional universe is a projection of all of this activity taking place on the two-dimensional plane made up of qubits.

THEORY TWO: QUANTUM IMMORTALITY

Most people have heard of Schroëdinger’s Cat regardless of whether or not you have studied physics, but for those who either haven’t heard of it or didn’t really understand what was up with this imaginary cat, let me explain.

Schroedinger’s Cat is a thought experiment that explores the idea of the wave function which is a mathematical way of describing an isolated quantum system as in a system or environment that does not exchange matter, energy, or information with its surroundings.

In this thought experiment, a cat is placed inside a box, along with something that could or could not kill. For this case, let’s say the cat has been placed in the box with a silent gun that could or could not go off at any moment. Once the box is sealed, there is no way to know whether the cat is dead or alive without opening the box. So, until you open the box and see that cat, technically, the cat is both alive and dead simultaneously [4].

What happens once you open the box? There are two ways we can look at this situation according to quantum physics.

1. Copenhagen interpretation: The box with the cat and weapon is considered an isolated system. Therefore, there exists a wave function that can be used to represent this situation. Once the wave function is interacted with by an observer opening the box and observing the cat, the wave function ‘collapses’. Once this collapse happens, that system is locked into one state. So, if the cat is alive, the wave function has collapsed into the state where the cat is alive. The state where the cat is dead has disappeared [5].

2. Multi Worlds Interpretation: The wave function for the cat-weapon system contains both possibilities, again the cat is technically both alive and dead until we open the box. In this interpretation, once the box is opened the wave function ‘splits’. Now, there is one universe where we open the box and the cat is alive and one universe where the cat is dead. We randomly fall into one of these universes and cannot access the other – like the parallel universe theory! Both universes are identical except for the cat and its state [6].

What does this mean for humans and our decisions?

Much like the cat, before we make a decision we exist in a state where we both have made the decision and not made the decision. For example, if you were standing in front of a grocery deciding whether or not to go in, once you make a decision the universe splits. In one universe, you have entered the store, and in another, you keep walking. Imagine how many universes have been created through even the smallest of decisions!

How does this relate to quantum immortality?

Have you ever been in a near-death experience? Maybe one where you were surprised you made it out alive? Well, following what we have discussed about the multi-world interpretation, quantum physics could tell us that there is both a universe where you survived and a universe where you did not. At that moment when you were close to death, the universe could have ‘split’ similarly to the examples we talked about before.

Quantum immortality takes this a step further to say that your consciousness will always follow the universe where you survive. So, in one universe you really did die, but your consciousness jumped to the nearest universe in which you survived and you would have no way of knowing. Or would you?

Content Warning: Mentions of suicide to follow. If you are sensitive to this topic, please skip to the next section.

In the parallel universe subreddit, the user u/-one-two-three- described what they believe to be their own experience of universe jumping after a near-death experience. This is what they had to say:

“So in 2014 is when I became aware of the Berenstain/Berenstein Bears Mandela effect. As a kid, I'm positive it was Berenstain Bears with an "A" but the Mandela Effect now said it was Berenstein Bears with an "E". I remember trying to copy the cursive writing and having difficulty with the "A." However, I can't prove my childhood memories to anyone, so I just accepted it was Berenstein the whole time and I misremembered.

In 2019 I attempted suicide and ended up in the ICU. A few months later, I looked up Berenstein Bears... and it was now Berenstain again. It was no longer an "E". It flipped back to an "A". I thought, "Oh ok, so the universe corrected itself and now it's Berenstain like it was when I was a kid."

The scariest part of this story for me, is I have a Facebook message to my best friend about the Berenstain Bears back in 2014 when I discovered the Mandela Effect. In this message, I tell her I remember Berenstein Bears always had an "E" as a kid and it shouldn't be spelled with an "A". I would have never written this, as it was definitely Berenstain with an "A" for me as a kid. I definitely remember typing this message to my best friend when I discovered the Mandela effect, but I complained to her about how it was spelled with an "E" now when it should have been spelled with an "A" like when we were kids. But when everything flipped, my complaints flipped too.

Now I'm wondering if I died and my parents are grieving in an alternate universe.”

THEORY THREE: SIMULATION THEORY

If you have been active on the internet at all in the past 20 years, then you have no doubt heard of this one before, but some new evidence has come out just this year that is making the possibility of us living in true reality even smaller.

This theory first came out back in 2003 with the paper Are We Living in a Computer Simulation by Nick Bostrom and was based on two big ideas:

1. Substrate-Independence: The philosophy of mind that believes that consciousness is not dependent on any particular physical substance or state. This theory states that thinking can “potentially operate in many different substances”[7]. Put simply, thinking and consciousness are not dependent on being a human with a brain, it could theoretically also be created by a computer.

2. Advanced civilizations with immense computing power would likely run ancestor-based simulations to see how they lived. With super-computing power, it would also be likely for this advanced civilization to run many of these simulations.

Simulation theory is based on the probability of whether we are living in what is called a ‘base universe’ which is a universe that is not a simulation and would contain the creators of simulations or a simulation. Since advanced civilizations in ‘base reality’ would likely make many simulations, the number of simulated universes would be higher than the number of advanced civilizations capable of creating simulations. Therefore, based on statistics, it is much more likely for a person to be living in one of the simulated realities rather than in true reality.

Earlier this year, Melvin Vopson published a paper talking about a new concept of information dynamics. Specifically, he proposed the Second Law of Infodynamics which states that information entropy is either constant or decreasing. This is opposite to the well-known Second Law of Thermodynamics which states that entropy is always increasing.

Let's take a moment to talk about entropy as that may be a word you are unfamiliar with. Simply put, entropy is the lack of order or predictability of a system. With this definition, the Second Law of Thermodynamics tells us that the particles that make up our universe are constantly becoming more unorganized; but there is an issue here. Technically, the universe is expanding without the loss or gain of heat which requires that the total entropy of the universe be constant – which goes against the laws of thermodynamics. This is where infodynamics comes in.

Vopson proposed that if entropy in the universe is measured as constant, then there must be another form of entropy that balances out the increasing entropy that comes from thermodynamics. He calls this other form of entropy: information entropy and according to this new Second Law of Infodynamics, it is always constant or decreasing [8].

According to Vopson, the constant increase of thermodynamical entropy is balanced out by the constant decrease in information entropy. This would explain why we observe entropy to be constant in the universe [8].

How does this support simulation theory?

The idea of information entropy is reminiscent of data optimization and compression in computers to reduce computational power and data storage requirements. So, we could be living in a simulated universe that is constantly compressing data so that it saves energy and memory. At least, according to this theory.

HONORABLE MENTION: BOLTZMANN BRAINS

How do you know you are a real person and not a randomly formed brain in the cosmos full of artificial memories that is momentarily hallucinating?

Now, scientists don’t really believe this theory but it is interesting to consider. The main idea behind Boltzmann Brains is that if the universe exists over an extremely long amount of time, unlikely events will happen. This includes the possibility that complex things will form out of random combinations of particles.

This theory is all about statistics, it is more likely for something resembling a human brain to form rather than a singularity that would eventually become the universe in the Big Bang simply because it is easier. This randomly formed brain would have false memories and would hallucinate the universe around it. So, according to this theory, it is possible that every memory you have is a lie but you would have no way of knowing. Not only that, but the universe and environment around you are simply the imagination of a brain floating in space that is doomed to a momentary existence [9].

CONCLUSION

Thank you for reading! I hope these theories don't make you too existential, but a healthy dose of existential dread can't hurt too much...Right?

SOURCES / SUPPLEMENTAL READING

1. Plato’s The Republic (Allegory of the Cave)

2. Voorhoede, De. “What Is a Qubit?” Quantum Inspire, www.quantum-inspire.com/kbase/what-is-a-qubit/.

3. “The Universe Is a Hologram and Other Mind-Blowing Theories in Theoretical Physics.” BrandeisNOW, www.brandeis.edu/now/2018/march/hologram-qubits-headrick.html.

4. “What Is Schrödinger’s Cat? (Definition, How It Works).” Built In, builtin.com/software-engineering-perspectives/schrodingers-cat#:~:text=Schr%C3%B6dinger%27s%20Cat%20is%20a%20thought, (or%20may%20not.

5. Faye, Jan. “Copenhagen Interpretation of Quantum Mechanics.” Stanford Encyclopedia of Philosophy, Stanford University, 31 May 2024, plato.stanford.edu/entries/qm-copenhagen/.

6. Vaidman, Lev. “Many-Worlds Interpretation of Quantum Mechanics.” Stanford Encyclopedia of Philosophy, Stanford University, 5 Aug. 2021, plato.stanford.edu/entries/qm-manyworlds/.

7. Han, Ce. “Theoretical quantum immortality and its mathematical authority.” Journal of Physics: Conference Series, vol. 1936, no. 1, 1 June 2021, p. 012015, iopscience.iop.org/article/10.1088/1742-6596/1936/1/012015.

8. Read the Reddit post for yourself: https://www.reddit.com/r/ParallelUniverse/comments/1g87wgq/think_i_shifted_after_a_suicide_attempt/

9. Thagard, Paul. “Energy Requirements Undermine Substrate Independence and Mind-Body Functionalism.” Philosophy of Science 89.1 (2022): 70–88. Web. https://www.cambridge.org/core/journals/philosophy-of-science/article/energy-requirements-undermine-substrate-independence-and-mindbody-functionalism/2BB3C2353EFF80F9D5805CDCEA8C3C89

10. Bostrom, Nick. “Are we living in a computer simulation?” The Philosophical Quarterly, vol. 53, no. 211, Apr. 2003, pp. 243–255, https://doi.org/10.1111/1467-9213.00309.

11. Orf, Darren. A Scientist Says He Has the Evidence That We Live in a Simulation, www.popularmechanics.com/science/environment/a60553384/covid-simulation/.

12. “The Boltzmann Brain - Higgs Centre for Theoretical Physics.” The Higgs Centre for Theoretical Physics, higgs.ph.ed.ac.uk/outreach/higgshalloween-2021/boltzmann-brain.