“I think therefore I am.” This is disputably the single piece of indisputable knowledge  that philosophy has produced in its entire existence. The one who vocalized this thought was the French philosopher René Descartes, who then went on to create something called the “brain in the jar” theory. The theory proposes that one’s consciousness is the only thing that truly exists and that the rest of the world is simply an illusion created by some malignant demon.

In 2003 an idea was proposed by philosopher Nick Bostrom called the Simulation theory. It is essentially Descartes’ idea of the brain in a jar, except that Bostrom attempted to prove why this could in fact be the reality of our existence as opposed to Descartes use of the idea as nothing more than a thought experiment. Bostrom’s theory boils down to these 3 propositions:

1)      Humans will go extinct before we are able to create simulations indistinguishable from reality.

2)      Humans will choose to not develop life-like simulations once they have the capacity to develop them.

3)      We are living in a computer simulation.

Now it may seem like a bit of a leap of logic from the first 2 propositions to the third and even the first two statements are not immediately obvious, so let us try to uncover the reasoning behind it.

The entire simulation theory is based on a few assumptions. The first is that we could develop powerful enough computers to simulate billions of fully functioning human minds as well as, well…an entire universe in the first place. This may seem impossible, but perhaps it isn’t quite as ludicrous as you imagine. Let us take a moment to explore the technological feasibility of this idea.

Our technology has reached a level where we can map a human brain down to the neuron in about 45 minutes’ time under an MRI scan. If the brain is the physical representation of the mind, then we could feasibly encode a functioning copy of a human brain. Additionally, let us take a stroll down videogame memory lane. The first computer was invented in 1833. The first videogame – Pong – came into being almost 140 years later, in 1972. Only 58 years later we have videogames that look almost photorealistic and digital body doubles in movies that can fool a large part of the audience.

Considering all of this, why is it inconceivable to imagine that we could eventually simulate an entire universe? In fact it has been suggested that we wouldn’t even need to do that! We could approach the simulation from the perspective of a solipsist and simply simulate only what we are interacting with. I personally, in this very moment, cannot verify the existence of say Alpha Centauri since I cannot directly observe it, so there is no need to simulate it unless I take out a telescope and point it in the direction of Alpha Centauri and even then all that I would need to see is a static 2D projection of the star as opposed to a fully functioning, simulated star system.

Thus, it is perhaps feasible that such levels of technological advancement could be achieved. If we assume that they are and that humanity does not end up disappearing either due to our own hubris or natural causes, then realistic simulations are possible. So why would we want to make them in the first place? Many reasons have been cited, such as ancestor simulations to explore and study our past, entertainment and scientific experimentation or perhaps even to attempt to test out political campaigns and propaganda before deploying them in the “real world”.

Now we come to the crux of the matter – are we living in a simulation?

Assuming that humanity develops the technology needed to create such a thing and then proceeds to deploy it then the answer becomes most likely yes! Imagine this – your race develops a simulation to explore your past and ancestry. The simulation runs out its course, but inside the simulation the humans who believe themselves to be real do the same thing that you did since they are playing out your past – they run a simulation of their past and the same happens in that simulation. Imagine this repeating over and over an infinite number of times. Hell, if you’re able to run a simulation, you probably wouldn’t run just one, so you’d have multiple branching infinities of simulations. The likelihood of us existing in the real world becomes miniscule!

Now that I’ve hopefully freaked you out a little bit it comes time to ask – what does this mean for us? How does this change the way we live our lives? Well, economist Robert Hanson suggests that we should attempt to be entertaining in order to avoid being deleted in case the simulation’s purpose is entertainment. He also posits that most simulations will probably not run the entire course of human history, but rather a shorter period of time, probably before some interesting or possibly disastrous historical event, so we should concentrate more on living in the moment and our own self-interests as we cannot know if there will even be a tomorrow or if the people we are so invested in helping or impressing are real or simply computer code. We should also probably avoid attempting to find out if we even live in a simulation, since if we did it would probably end, and our lives would be forfeit.

Ultimately however, most philosophers and scientists agree that Simulation theory is impossible to conclusively prove or disprove, though some have tried, so we should live our lives like we would anyway, because whether you are flesh and blood or advanced computer code, that is not what defines us as people, so we shouldn’t set too much store by it.