Are we living in a Simulation?
The short answer is NO WE ARE NOT. You can stop reading here if your curiosity has been satisfied. If you are one of the increasingly scarce people in the world who still insist on thinking for themselves I will devote the rest of this blog to supporting my contention. I never felt compelled to think about this question until I recently realized that many of my “intelligent” friends have taken the musings of various famous futurists to heart and decided that this is a serious physics question. At first I thought they had just watched too many reruns of The Matrix but then I started hearing it in the popular press from luminaries like Elon Musk;
The first problem with providing a rational answer to this question is that it really can’t be formulated as a rational question. What do you mean by living in a simulation?
- There is another universe with physical laws identical to our own which is running a computer that is based on a Turing design that is simulating us?
- There is another universe beyond ours with magical new incomprehensible physics laws that make it possible for a non-Turing based computer to be simulating us but the word “simulation” still means the same thing?
There are many others but let’s just examine these two to see if we can grapple with the questions they present before introducing more. One is easy to address… our universe cannot be simulated with a Turing like computer… or we wouldn’t think Quantum computers were an exciting idea. A Turing based computer cannot compute the physics we experience so we are definitively NOT living in a simulation running inside any kind of computer design that the human race has yet conceived of. This observation is the basis of my related contention that we CANNOT simulate a living organism or a brain with a man-made computer nor will we be uploading our souls to one anytime soon. Our computers simply do not have the capacity to compute the kind of physics that makes life and thought possible. If they could… we would be able to simulate a quantum computer with a Turing computer and we can’t do that either! So question one is silly because any competent computational physicist can decisively observe that we can’t compute real-physics with our toy computers. Making them faster with more bits doesn’t change that problem either, ever.
Now let’s tackle number two… what if magic is allowed? Can there be some external Universe governed by different or better laws than our own that make simulating THIS Universe possible for some other kind of computer design that is NOT like a Turing machine? Fortunately we can answer this question EVEN with “magic” allowed. The math physicists use to describe the relationships between the forces of nature are the same in ALL possible Universes. Physics fails in EVERY universe in which Pi is not exactly Pi. In other words, even God couldn’t change the value of Pi if he wanted to. So if we ARE living inside a simulation, it is a simulation that is robust enough to allow us to employ mathematical tools that tell us about the properties of any possible EXTERNAL host universe. However the fact that Pi has the same value in any universe also tells us that irrational numbers and infinitesimal numbers that we only know how to compute with infinitely iterated recursive functions also have to be computable to unlimited precision instantly by any host universe. How much energy does it take to instantly compute an infinite number series? It takes an INFINITE amount of energy. Can we or any advanced civilization make a computer that can harness an infinite amount of energy? Not that we can conceive of at the moment (without requiring MAGIC) so no.
Humans have derived some amazing mathematics over the past 120 years that describe our universe with remarkable mathematical precision. That math also tells us a great deal about the limits of any new answers we may find to the remaining unanswered questions of physics. Until the era of string-theory in the 1980’s it appeared that our universe was <almost> fully described by just two primary theories. Quantum Mechanics and Relativity. These theories had their aesthetic flaws but their powers for describing the observable properties of our universe where indisputable. The aesthetic flaws however were impossible to ignore;
- The Universe seemed to require the EXACT cancellation of infinitesimal values to compute correctly
- The Universe seemed to require of a few magical constants that were essential to physics working for no explicable reason
- The two theories couldn’t agree on how gravity worked
- The most interesting math that seems to describe physics is beyond our capacity to compute
String theory, culminating in M-theory, blossomed in the 1990’s and seemed to provide answers to these fundamental questions while generating many more. We had discovered exotic new math that seemed to enable us to compute the fundamental particles and constants of physics and provided tools for canceling some of the massive infinities that arose from trying to analyse even the simplest physical systems. String theory even gave us answers to what happens inside singularities and what was the universe before the Big-Bang. Unfortunately many of those answers were hauntingly unsatisfying, because more often than not, string theory told us a lot about the limits of what we know how to compute. Suffice it to say that M-theory provides answers to some of the apparent flaws in classical physics that may have appeared to make the universe look computationally manageable when in fact it was not.
The short of it is that the universe we live in appears to compute infinitesimal values with infinite precision instantly. That takes infinite energy to compute, which means we probably aren’t living inside an advanced alien civilization teenagers gaming PC as a simulation because their PC would need to consume all of the energy in their universe to function, which would cause their parents to unplug the sim when they received their infinite power bill.
So what if you harnessed the apparently infinite computing resources of physics to simulate another world? Then it wouldn’t be a “simulation”, it would be the real universes’s physics computing us. Inversely, we can’t make a Turing computer that simulates a quantum computer… if we could we wouldn’t need quantum computers… If we built a super fast quantum computer using qbits to simulate it, that computer would NOT be able to simulate quantum computing because the act of reading a qbit destroys its quantum state. We would therefore need an infinite number of qbits to simulate a qbit… whoops… Since we live inside a universe that can perform quantum calculations… we’re once again… not living in a simulation. If we were living inside a simulation that could simulate quantum mechanics then we would not be INSIDE the sim unless you got really creative at contriving a definition of “simulation” that was indistinguishable from being made out of the same physics as the ones employed by the host universe?
The circularity of the last point also suggests that the idea of a “simulation” is a purely human contrivance based on the false assumption that it is even possible to compute us with a finite machine. So let’s summarize where we are at before we proceed;
- Our universe appears to require infinite energy to compute. No finite, bounded machine, however large can encompass such a calculation.
- We know that a Turing computer can’t compute our universe… so it can probably also never simulate life or download our minds either.
- A quantum computer can’t simulate a quantum computer. The act of reading a qbit destroys it’s “quantumy” properties, sending us back to needing infinite energy again even if our world was a simulation running inside a quantum computer.
- God can’t change the value of Pi or any other infinitesimal numbers physics requires, so there can be no external universe that obeys new mathematical laws we can’t fathom from here.
So we almost certainly live in the root universe. We may occupy an extremely tiny isolated atoll of The Universe that is uniquely qualified to support life as we know it. We MAY be cut off from physical visibility into The Universe beyond the boundaries that enable our survival but if physics has taught us anything it is that we have been very successful at employing the powers of mathematics to infer information far beyond the confines of our own local environment.
If the answer is relatively straight forward why are great minds debating it? One answer is it’s just a new version of the God debate we’ve been having for centuries. A more interesting answer is that we DO live inside a simulation but not one of any grand scale. The simulation we live inside is between our ears. As much as we like to think of human intelligence, a human brain is really pretty constrained by its limited computing resources. In order to “place” itself in reality the human brain, comprised of about a grapefruit volumes worth of cells and consuming roughly 25 Watts of power has to fabricate a model of the world it is trying to survive in. Our minds cut a LOT of corners in order to hallucinate a model of reality that is complex enough to give us an edge on survival but simple enough to run in real-time so that we can make snap life-or-death survival decisions without needing hours to analyse our survival options when say, we are attacked by a shark. That said the human mind is a remarkable learning machine, it constantly strives to understand and invent models of natural forces that it can use to predict future events based on current circumstances. What does the human mind substitute for a problem it can’t solve or hasn’t solved yet? It may put a TBD marker on the question so that when we have an unresolved thought like, “I wonder why something exists instead of nothing” the brain, which has no way to answer the question, just substitutes an intelligent entity like itself that has or will eventually find the answer to that question. “How does a jet engine work?” Somebody smarter than me figured it out! “How do Amoeba’s work?” Somebody smarter than me made them! Makes perfect sense, right?
So we do live in a crude simulation fabricated by our minds which vastly over-simplifies many things in order to always operate in real-time. The bad simulation of reality is easily breached and we do it often when we analyze the world rationally and use the tools of mathematics and scientific method to carefully define the boundary between how we imagine The Universe works and how it can be PROVEN to actually work. Our minds impose a primitive, instinctual survival filter in front of the real properties of The Universe we inhabit causing us to view it irrationally. Rational thinking is slow, demanding, not suitable for immediate survival and often unrewarding. It requires a great deal of discipline to adhere to while our instincts constantly try to steer us towards believing quicker more appealing ideas that require less work to comprehend and simulate. We crave trite answers to incomprehensible problems. Our minds would not be able to function in a real-time world if we were not constantly forced to surrender to the constraints of our limited computing resources by frequently embracing simplicity over reality, or instinct over reason. This is the intellectual paradox of being human that results in seemingly brilliant scientific minds claiming that they are using computers to model human minds, the climate, creating artificial intelligence or are on the brink of finally getting the Start Menu right in Windows 11.
- We don’t live in a sim
- We CAN’T live in a sim so we can never be uploaded to a computer
- The universe can’t be simulated but our brains are stupid and easily fooled so there is hope for virtual reality
- Because we are stupid we can IMAGINE that we live in a simulation and something as dumb as we are that is NOT us might be possible to simulate on a computer.
- ergo, there will be no “Artificial Intelligence” like us simulated by a computer there will only be real-intelligence. The are no ACTUAL advances in “Artificial Intelligence” taking place, just advances in computing.