What If Humanity Lives In a Level III Multiverse? | Unveiled

What If Humanity Lives in a Level III Multiverse?

According to the famed philosopher Arthur Schopenhauer, truth must go through three phases before it’s accepted in the mainstream. First, it’s ridiculed by others, then it’s vehemently challenged, and finally, it’s accepted as a self-evident truth. The idea of parallel universes isn’t quite at the last phase yet, but it’s long past the first. This concept is now entering the mainstream in a big way, which means the race is on to truly understand it.

So, this is Unveiled and today we’re answering the extraordinary question; what if humanity lives in a Level Three multiverse?

Among the numerous proponents of the multiverse, physicist Max Tegmark is one of the most ardent defenders of it. Across various interviews and papers, he’s suggested that if you accept quantum mechanics to be true (which most of the scientific world does) then you must also accept that parallel universes are true, too. This is because the multiverse isn’t so much a theory as it is a prediction. A prediction regarding the nature of the universe based on past observations and established principles. Max Tegmark has, then, put forward his own model of the multiverse, that’s broken up into four different levels of complexity. And, while many scientists are opposed to ideas that are generally deemed unverifiable (as it might be argued that the multiverse is), Tegmark insists that there’s good reason to believe. And who knows, it may one day be possible to test the very fabric of reality, anyway.

Tegmark’s theory begins with a Level One multiverse, which rests on the pretty simple foundation that the universe is infinite, and that matter is spread evenly throughout it and not just gathered together in the parts we can observe. These ideas are both widely supported by modern scientific observations, so Tegmark’s Level One is by far the least controversial part of his multiverse theory. After all, if we take those observations to their natural conclusion, we inevitably find that an infinite universe gives rise to a limitless number of particle variations. This means that there should likely be a clone of you, or even infinite clones of you, spread throughout an unending reality… and that any possible world you can think of (within the laws of physics) will happen eventually across a Level One multiverse. Moving between these worlds and meeting these clones is difficult if not impossible, however, purely due to the immense distances at play. Nevertheless, Tegmark asserts that Level One, at least, appears to fit with the contemporary scientific view.

But today we’re leaving the relatively safe ground of Level One and powering straight through to Level Three, because here is where the multiverse begins to truly take on a new shape. Tegmark’s Level Three predominantly rests on the theory of quantum physics, and whenever quantum physics is involved… stuff in general gets weird. The Many Worlds Interpretation of Quantum Mechanics was first put forward by the physicist Hugh Everett III in the 1950s, and it’s this idea that forms the basis of Level Three.

In the Many Worlds Interpretation, the universe is dictated by quantum events, and all outcomes have a home. Let’s take the simplest action of chance - a coin toss. In a Many Worlds reality, when someone flips a coin, they’re put into a state known as superposition, which means they exist in more than one state at once. The coin will then land both heads and tails, and the observer will be both excited and disappointed by the outcome at the same time. A Level Three multiverse splits at this point, however, creating one true reality where heads landed and another true reality where tails did. Both are equally real. So the theory goes, these realities then exist all around us, but in an abstract realm rather than in identifiable reality.

Surprisingly, a Level Three multiverse doesn’t allow for any new possibilities beyond the somewhat physically restrained Level One or the physically free Level Two (which we’ll explore in depth in a future video). Instead, it might be argued that Level Three is more to do with populating a multiverse. With explaining how so many multiple universes (infinite, in fact) come into being. The quantum branching at the heart of this model - the heads and tails superposition - simply creates fresh worlds all the time, but none of those worlds are governed by anything new. They all follow the same physical laws that dictate Tegmark’s first two levels. In essence, then, the only major difference in Level Three is where these other worlds are found. For example, while in Level One all worlds are some fixed distance away from us in space, at Level Three they exist all around us, all the time, but in another realm entirely. There are whole plains of reality that kind of whisper around our lives, but we can’t see, feel, or experience them.

Time also works a little differently in a Level Three multiverse, though. The traditional view is that time is what allows change. So, whenever a difference is detected in a system - leaves have fallen, flowers have grown, or the tide has gone out, for example - we know that time has taken place. The Level Three framework sees it differently, though, instead viewing time as the sequencing from one universe to the next. So, when you flip a coin and it lands on heads, the shift between possible universes - from the one with tails to the one with heads - is time. So now, time is little more than the ordering of all the specific, possible universes that constitute your life. Which is perhaps enough to trigger an existential crisis, or two.

What’s more, it arguably figures that somewhere within a Level Three multiverse the existence of a Level Three multiverse is widely known - and not just theorised, as it is in this reality. But also, as a result of all the countless decisions and splits within your own life, there’s somewhere where it turns out that you are the one to have proven Level Three to the rest of the world. It might be pitched, then, that this kind of multiverse operates as though for everyone and everything, all the time, it’s just that we’re only conscious of one infinitely small slice of it at any given moment (and during any given lifetime).

These aren’t the only bizarre considerations that Level Three inspires, however. For example, there could be implications for immortality. If there really are unlimited versions of you that branch out at every possibility, essentially co-existing in the tight and endless mesh of reality, then there’s at least one of you that survives every accident. And, depending on whether it’s ever physically possible, there’s at least one of you that lives forever. Say you’re in a car accident where the chances of survival are 50/50. Your life is placed into a state of superposition, out of which comes two possibilities and two universes… one where you live, and one where you die. Within the one in which you live, say you were then involved in another car accident the following day. The chances of surviving both events drop to twenty-five percent, but still at least one version of you inevitably does survive. The following day, there’s another accident, and your chances drop again. And then another, and another. This could continue until your chances of survival are infinitesimal… but still, even were there to be a 0.00001 percent chance, at least one of you somewhere will survive in a Type Three multiverse. It’s an idea that’s tied up with another thought experiment, explored by Max Tegmark and others in the past, known as quantum immortality. In this version of the multiverse, it seems there truly is no end.

As such, the idea of existing at Level Three might feel strange, or maybe frightening, but it of course matters little with regard to our day-to-day lives. Scientists are continually searching for the secrets to reality, but until such day as those secrets are revealed perhaps its best to simply enjoy (and engage with) the experience as we live it. And, ultimately, we’re not done yet… because going by the Tegmark model, there’s at least one further level of the multiverse to go - Level Four- which we’ll explore in a future video.

So, keep your eyes peeled for that. And, in the meantime, consider that were Level Three ever to be proven, then it would from some perspectives be cause for some serious celebration. For dancing in the streets, and throwing huge, interdimensional-ly aware parties. Because it would show that all possibilities really are achievable for us. So, we should never give up hope, nor stop trying to make this universe one of the greatest you’ve ever seen. And that’s what would happen if humanity lived in a Level Three multiverse.