If you believe that some lifeform can, or will one day have the ability to, create a simulation of the universe, then there is almost an absolute certainty that we are living inside a simulation right now.
What is a universe simulation? Essentially, it would be the physical universe recreated in software similar to a video game. Conscious entities would be modeled and would interact inside the software like we do in the real world. So, in order to simulate a universe, software architects would need to be able to engineer consciousness. If you believe in the big bang theory, then you believe that consciousness can occur on its own if pressure is applied to matter and that matter is allowed to sit for long enough. According to the big bang theory everything in the universe, living or inanimate, came from dust. Somehow dust became cells, those cells combined to create organisms, and at some point became conscious. Physics proves to us that our physical world can be described by mathematical equations. You can calculate how long it will take for an apple to fall from a tree and you can calculate the exact position Saturn will be 10 million years from now. With the right information computers can model every phsical interaction in our universe. If consciousness can occur in the physical world, is it not inconceivable that consciousness will one day be able to be modeled in the digital world as well? Whether or not consciousness can be created artificially is a topic that requires much more detail than I can fit into this article. The debate and impact of this is philosophically and morally controversial. For the sake of this theory we assume that consciousness can, or one day will be able to, be simulated.
Think about video game advancement in recent history. The same people that grew up playing Atari, can now submerse themselves in video games with sophisticated artificial intelligence and lifelike graphics that blur the lines between simulation and reality. This advancement happened in a single generation. How much further will mankind advance, technologically, in the next generation? And, how many generations are left to come? Considering our historic rate of technological advancement and the fact that there is no end to human civilization within sight, is it crazy to believe that we will eventually be able to create a simulation of the universe? The theory is not limited to our planet, either. If any lifeform on any planet has reached the point where they can create a simulation of the universe or will reach that point, then its almost certain that we are living in a simulation right now.
In a universe simulation, conscious entities inside the simulation would have no idea that they are simulations and would behave the same as what they were modeled after. That means that artificial entities within the simulation would be able to develop and advance their own technologies and eventually create simulations of their own. Entities in sub-simulations would be able to create simulations of their own as well. So as soon as the first lifeform creates the first simulation, more and simulations will follow with exponential growth in quantity. This is where the mathematical certainty comes from. If you haven’t written the logic off thus far, then you believe in a point in time where there is one universe where residents are living conscious beings, and uncountable simulations within simulations containing conscious entities that believe they are real but are actually software. The probability that a we are living in the single real universe, and not one of the near infinite simulated universes, is close to zero. Honestly, would it even matter if we were in a real or simulated universe anyway?
I’ve kept my opinion out of this article, but now I would like to give my personal take on this. I find it so difficult to truly understand what consciousness is, that I find it unbelievable that consciousness will ever be able to be simulated. Also, I don’t believe in the big bang theory in its current form. I believe that the universe is expanding, but I don’t believe that expansion originated from a singularity. I also don’t believe that inanimate matter can become conscious life without intelligent design. I am a Christian, so this is where God comes into the equation for me. And to me it does matter whether we live in a real or simulated universe. I do not believe that love, hate, grief, joy, and all of the other indescribable aspects of life can be modeled by any combination of mathematical equations. I really enjoy reading about topics like this and I try to always keep an open mind. Despite logical arguments, some theories like Siumlation Theory are just a little too far fetched for me. It might be a defense mechanism, but hey that’s human!
Before I wrap up this article, I want to post a link to my favorite commentary on Simulation Theory. Warning, there is some vulgar language. I don't think I'll ever grow up.