The Simulation Hypothesis -- Not Nearly Crazy Enough to Be True

The "Simulation Hypothesis", the idea that our universe is some sort of computer simulation, has been getting more and more airtime lately.  

The rising popularity of the meme is not surprising since virtual reality and associated tech have been steadily advancing, and at the same time physicists have further advanced the formal parallels between physics equations and computation theory.    

The notion of the universe as a computer simulation does bring to the fore some important philosophical and scientific concepts that are generally overlooked.  

However, in various online and real-world conversations I have been hearing various versions of the simulation hypothesis that don't make a lot of sense from a scientific or rational point of view.   So I wanted to write down briefly what does and doesn't make sense to me in the simulation-hypothesis vein...

One thing that has gotten on my nerves is hearing the simulation hypothesis used to advocate for religious themes and concepts -- often in ways that profoundly stretch logic.   There are some deep correspondences between the insights of mystical wisdom traditions, and the lessons of modern physics and computation theory -- but I have heard people talk about the simulation hypothesis in ways that reach way beyond these correspondences, in a ways that fallaciously makes it seem like the science and math give evidence for religious themes like the existence of a vaguely anthropomorphic "creator" of our universe.  This is, I suppose, what has led some commentators like AGI researcher Eray Ozkural to label the simulation hypothesis a new form of creationism (the link to his article "Simulation Argument and Existential AI Risk: New Age Creationism?" seems to be down at the moment).

The idea that our universe might be a computer simulation is not a new one, and appeared in the science fiction literature many times throughout the second half of the previous century.   Oxford philosopher Nick Bostrom's essay titled "The Simulation Argument" is generally credited with introducing the idea to the modern science and technology community.    Now Rizwan Virk's book titled "The Simulation Hypothesis" is spreading the concept to an even wider audience.   Which is part of what motivated me to write a few words here on the topic.

I don't intend to review Virk's book here, because frankly I only skimmed it.   It seems to cover a large variety of interesting topics related to the simulation hypothesis, and the bits and pieces I read were smoothly written and accurate enough. 

Fundamentally, I think the Simulation Hypothesis as it's generally being discussed is not nearly crazy enough to be true.  But it does dance around some interesting issues.

Bostrom's Rhetorical Trickery

I have considerable respect for Nick Bostrom's rhetorical and analytical abilities, and I've worked with him briefly in the past when we were both involved in the World Transhumanist Association, and when we organized a conference on AI ethics together at his Future of Humanity Institute.   However, one issue I have with some of Nick's work is his tendency to pull the high school debating-team trick of arguing that something is POSSIBLE and then afterward speaking as if he has proved this thing was LIKELY.   He did this in his book Superintelligence, arguing for the possibility of superintelligent AI systems that annihilate humanity or turn the universe into a vast mass of paperclips -- but then afterward speaking as if he had argued such outcomes were reasonably likely or even plausible.   Similarly, in his treatment of the simulation hypothesis, he makes a very clear argument as to why we might well be living in a computer simulation -- but then projects a tone of emphatic authority, making it seem to the naive reader like he has somehow shown this is  a reasonably probable hypothesis.

Formally what Bostrom's essay argues is that

... at least one of the following propositions is true: (1) the human species is very likely to go extinct before reaching a “posthuman” stage; (2) any posthuman civilization is extremely unlikely to run a significant number of simulations of their evolutionary history (or variations thereof); (3) we are almost certainly living in a computer simulation.

The basic argument goes like this: Our universe has been around 14 billion years or so, and in that time-period a number of alien civilizations have likely arisen in various star systems and galaxies... and many of these civilizations have probably created advanced technologies, including computer systems capable of hosting massive simulated virtual-reality universes.   (Formally, he argues something like this follows if we assume (1) and (2) are false.)   So if we look at the history of our universe, we have one base universe and maybe 100 or 1000 or 1000000 simulated universes created by prior alien civilizations.   So what are the odds that we live in the base universe rather than one of the simulations?  Very low.  Odds seem high that, unless (1) or (2) is true, we live in one of the simulations.

The obvious logical problem with this argument is: If we live in a simulation programmed by some alien species, then the 14 billion year history of our universe is FAKE, it's just part of that simulation ... so that all reasoning based on this 14 billion year history is just reasoning about what kind of preferences regarding fake evidence were possessed by the aliens who programmed the simulation we're living in.   So how do we reason about that?   We need to place a probability distribution over the various possible motivational systems and technological infrastructures of various alien species?

(For a more detailed, slightly different run-through of this refutation of Bostrom's line of argument, see this essay from a Stanford University course).

Another way to look at it is: Formally, the problem with Bostrom's argument is that the confidence with which we can know the probability of (1) or (2) is very low if indeed we live in a simulation.   Thus all his argument really shows is that we can't confidently know the probabilities of (1) and (2) are high -- because if we do know this, we can derive as a conclusion that the confidences with which we know these probabilities are low.

Bostrom's argument is essentially self-refuting: What it demonstrates is mostly just that we have no frickin' idea about the foundational nature of the universe we live in.   Which is certainly true, but is not what he claims to be demonstrating.  


An Array of Speculative Hypotheses

To think seriously about the simulation hypothesis, we have to clearly distinguish between a few different interesting, speculative ideas about the nature of our world.  

One is the idea that our universe exists as a subset of some larger space, which has different properties than our universe.   So that the elementary particles that seem to constitute the fundamental building-blocks of our physical universe, and the 3 dimensions of space and one dimension of time that seem to parametrize our physical experience, are not the totality of existence -- but only one little corner of some broader meta-cosmos.  

Another is the idea that our universe exists as a subset of some larger space, which has different properties than our universe, and in which there is some sort of coherent, purposeful individual mind or society of individual minds, who created our universe for some reason.

Another is that our universe has some close resemblance to part or all of the larger space that contains it, thus being in some sense a "simulation" of this greater containing space...

It is a valid philosophical point that any of these ideas could turn out to be the reality.    As philosophy, one implication here is that maybe we shouldn't take our physical universe quite as seriously as we generally do -- if it's just a tiny little corner in a broader meta-cosmos. 

One is reminded of the tiny little Who empire in Dr. Seuss's kids' book "Horton Hears a Who."   From the point of view of the Whos down there in Whoville, their lives and buildings and such are very important.   But from Horton the Elephant's view, they're just living in a tiny little speck within a much bigger world.

From a science or engineering view, these ideas are only really interesting if there's some way to gather data about the broader meta-cosmos, or hack out of our limited universe into this broader meta-cosmos, or something like that.   This possibility has been explored in endless science fiction stories, and also in the movie The Matrix -- in which there are not only anthropomorphic creators behind the simulated universe we live in, but also fairly simple and emotionally satisfying ways of hacking out of the simulation into the meta-world ... which ends up looking, surprise surprise, a lot like our own simulated world.  

The Matrix films also echo Christian themes in very transparent ways -- the process of saving the lives and minds of everyone in the simulation bottoms down to finding one savior, one Messiah type human, with unique powers to bridge the gap between simulation and reality.   This is good entertainment, partly because it resonates so well with various of our historical and cultural tropes, but it's a bit unfortunate when these themes leak out of the entertainment world and into the arena of supposedly serious and thoughtful scientific and philosophical discourse.

In a 2017 article, I put forth some of my own speculations about what sort of broader space our physical universe might be embedded in.   I called this broader space a Eurycosm ("eury" = wider), and attempted to explore what properties such a Eurycosm might have in order to explain some of the more confusing aspects of our physical and psychological universe, such as ESP, precognition, remote viewing reincarnation, mediumistic seances, and so forth.   I don't want to bog down this article with a discussion of these phenomena, so I'll just point the reader who may be interested to explore scientific evidence in this regard to a list ofreferences I posted some time ago.   For now, my point is just: If you believe that some of these "paranormal" phenomena are sometimes real, then it's worth considering that they may be ways to partially hack out of our conventional 4D physical universe into some sort of broader containing space.

As it happens, my own speculations about what might happen in a Eurycosm, a broader space in which our own physical universe is embedded, have nothing to do with any creator or programmer "out there" who programmed or designed our universe.    I'm more interested to understand what kinds of information-theoretic "laws" might govern dynamics in this sort of containing space.

What seems to be happening in many discussions I hear regarding the simulation hypothesis is: The realization that our 4D physical universe might not be all there is to existence, that there might be some sort of broader world beyond it, is getting all fuzzed up with the hypothesis that our 4D physical universe is somehow a "simulation" of something, and/or that our universe is somehow created by some alien programmer in some other reality.

What is a "simulation" after all?  Normally that word refers to an imitation of something else, created to resemble that thing which it simulates.   What is the evidence, or rational reason for thinking, our universe is an imitation or approximation of something else?

Simulations like the ones we run in our computers today, are built by human beings for specific purposes -- like exploring scientific hypotheses, or making entertaining games.    Again, what is the evidence, or rational reason for thinking, that there is some programmer or creator or game designer underlying our universe?   If the only evidence or reason is Bostrom's argument about prior alien civilizations, then the answer is: Basically nothing.

It's an emotionally appealing idea if you come from a Christian background, clearly.   And it's been funky idea for storytelling since basically the dawn of humanity, in one form or another.   I told my kids a bunch of simulation-hypothesis bedtime stories when they were young; hopefully it didn't twist their minds too badly.   My son Zebulon, when he was 14, wrote a novel about a character on a mission to find the creators of the simulation we live in, so as specifically to track down the graphic designer who had created the simulation, so as to hold a gun to his head and force him to modify the graphics behind our universe to make people less ugly.   Later on he became a Sufi, a mystical tradition which views the physical universe as insubstantial in much subtler ways.

There is good mathematics and physics behind the notion that our physical universe can be modeled as a sort of computer -- where the laws of physics are a sort of "computer program" iterating our universe through one step after the next.    This is not the only way to model our universe, but it seems a valid one that may be useful for some purposes.  

There is good philosophy behind the notion that our apparently-so-solid physical reality is not necessarily foundationally real, and may be just a tiny aspect of a broader reality.   This is not a new point but it's a good one.   Plato's parable of the cave drove this home to the Greeks long ago, and as Rizwan Virk notes these themes have a long history in Indian and Chinese philosophy, and before that in various shamanic traditions.   Virk reviews some of these predecessors in his book.

But there is nothing but funky entertainment and rampant wishful thinking behind the idea that our universe is a simulation of some other thing, or that there is some alien programmer or other vaguely anthropomorphic "creator" behind the origin or maintenance of our universe.

We Probably Have Very Little Idea What Is Going On

I have two dogs at home, and I often reflect on what they think I am doing when I'm sitting at my computer typing.  They think I'm sitting there, guarding some of my valued objects and wiggling my fingers peculiarly.   They have no idea that I'm controlling computational processes on faraway compute clouds, or talking to colleagues about mathematical and software structures.  

Similarly, once we create AGI software 1000 times smarter than we are, this software will understand aspects of the universe that are opaque to our little human minds.   Perhaps we will merge with this AGI software, and then the new superintelligent versions of ourselves will understand these additional aspects of the universe as well.    Perhaps we will then figure out how to hack out of our current 4D spacetime continuum into some broader space.   Perhaps at that point, all of these concepts I'm discussing here will seem to my future-self like absolute ridiculous nonsense.

I have a lot of respect for the limitations of human intelligence, and a fairly strong confidence that we currently understand a very minimal percentage of the overall universe.   To the extent that discussion of the simulation hypothesis points in this direction, it's possibly valuable and productive.   We shouldn't be taking the 4D spacetime continuum current physics models as somehow fundamentally real, we shouldn't be assuming that it delimits reality in some ultimate and cosmic sense.

However, we also shouldn't be taking seriously the idea that there is some guy, or girl, or alien, or society or whatever "out there" who programmed a "simulation" in which our universe is running.   Yes, this is possible.   A lot of things are possible.  There is no reason to think this is decently probable.

I can see that, for some people, the notion of a powerful anthropomorphic creator is deeply reassuring.   Freud understood this tendency fairly well -- there's an inner child in all of us who would like there to be some big, reliable Daddy or Mommy responsible for everything and able to take care of everything.   Some bad things may happen, some good things will happen, and in the end Mom and Dad understand more than we do and will make sure it all comes out OK in the end.   Nick Bostrom, for all his brilliance, seems repeatedly drawn to themes of centralized control and wisdom.   Wouldn't it be reassuring if, as he suggests in Superintelligence, the UN would take over the creation of AGI and hire some elite vetted AI gurus to make sure it's developed in an appropriate way?   If we can't have a Christian God watching over us and assuring us a glorious afterlife, can't we at least have an alien programmer monitoring the simulation we're running in?  Can't the alien programmer at least be really good looking, let's say, maybe like a Hollywood movie star?

As far as I can tell, given my current sorely limited human mind, the universe seems to be a lot more about open-ended intelligence, a concept my friend Weaver at the Global Brain Institute has expertly articulated.   The universe -- both our 4D physical spacetime and whatever broader spaces exist beyond -- seems to be a complex, self-organizing system without any central purpose or any centralized creator or controller.   Think the creative self-organizing ocean in Lem's Solaris, rather than bug-eyed monsters coming down in spaceships to enslave us or stick needles into our bellybuttons.

So the simulation hypothesis takes many forms.   In its Bostromian form, or in the form I often hear it in casual conversations, it is mostly bullshit -- but still, it does highlight some interesting issues.   It's a worthwhile thought experiment but in the end it's most valuable as a pointer toward other, deeper ideas.   The reality of our universe is almost surely way crazier than any story about simulations or creators, and almost surely way beyond our current imaginations.