Simulation Theory:
Where Do Universes Come From?
Synopsis: Lots of people from Elon Musk to Neil deGrasse Tyson are suggesting that we might live in a simulation. This article lays out a logical foundation for those beliefs.
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There is no debate that our universe started, even though this was once in dispute as scientists initially believed our universe was infinite in both space and time. The best theory currently available for how it started is that it was created in a Big Bang. This is the scientific theory. The other popular theory is that it was created by one or more gods, the specifics of which vary widely by religion. But we’ll get back to that.
Assuming that our universe was created by a Big Bang, how did it occur? Where seems like a more natural word to use in this context, given that the intent is to frame the event that created the universe in some form of context. When the Big Bang occurred, where did it occur? Was it something from nothing (which would, in fact, mean there is no where) or did it occur in some other way (there are various “many worlds” theories to choose from, for example) or did something cause it to be created?
Any discussion of this type must shift from a primarily scientific one to a more philosophical one, as we are unlikely to ever have observational evidence of what, if anything, is outside of our universe.
Exploring these ideas, we can deduce that our current universe potentially spawned in one of five ways, or more accurately, from one of five precursors.
1. Nothing.
From a scientific point of view, there is an argument to be made that nothing is the same as primordial energy because quantum or other unsteady states are constantly in flux and that nothing will always be something. It could also be the case that our universe is the first and that there was nothing before it.
2. Some type of primordial energy.
This possibility, which could be equivalent to nothing in some models, can be imagined as a bubbling cauldron where universes are constantly exploding into being or collapsing. While this visualization is not how such a scenario would manifest, the metaphor makes it easier for us to understand.
3. A higher dimension.
This may speak to the actual definition of a universe, which is generally defined as all of time and space. There are many ways in which universes could form from higher dimensions including the intersection of dimensions, a random subset, a subset existing in limited dimensions, or creation by higher-dimensional beings.
4. Another universe.
Our universe could be a creation of another universe; perhaps our universe is a simulation or a science experiment.
5. Forks.
There are potential scenarios where new universes are created via forks from existing universes. One example of a fork would be a variation of the quantum mechanics concept known as the many-worlds interpretation in which every choice is possible and each choice effectively becomes a new universe as it branches or splits. This means all possible futures and pasts occur. Or, as another example, we could be living in a simulation that is altered and restarted from various points in its timeline.
First and Second-Order Paths
From each of these starting points it is logically possible to describe how a universe like ours could come to exist. There are, however, significant differences between these paths. We will call the first two paths, from nothing or from primordial energy, first-order because they do not have any prerequisites. The second-order paths, a higher dimension, another universe, or a fork, require some form of precursor.
This is a very important distinction because if our universe is a first-order universe it means we are not the creation of something else. Many universes may have spawned at the same time, but ours is among the first generation. Most humans want to believe we are a first-order creation in the same way that during the earlier days of scientific thinking, it was common to put the Earth at the center of everything.
This type of thinking was also reinforced or amplified by the limits of the observational tools available and the general lack of scientific foundations such as advanced mathematics, of that period. From a purely philosophical view, the hubris of humanity drives us to imagine ourselves as occupying a central place in the world (and hence the universe) around us.
Further, many desire to imagine that we occupy a special place in a universe created especially for us by a supernatural (as in, outside nature, whether a god as we commonly understand that term, or a computer programmer in whose simulation we exist) agency.
Since the Copernican Revolution it has become abundantly clear that Earth is definitively not the center of the universe. As astronomy and cosmology continue to advance they are constantly reinforcing the fact that we hold no particular cosmic importance.
Interestingly, the second-order paths necessarily include all the scenarios in which higher beings (i.e., gods, creators) are involved in the creation of our universe. This is definitionally true because all those paths unambiguously state that our universe came from something else. In these divine paths, that something else is either another universe or a higher dimension, home to the creator(s). But, for clarity, higher beings are not a requirement for a second-order path.
If one accepts the second-order paths as possible, it logically follows that if our universe could be created in such a way then so could other universes. In fact, it seems that if our universe were spawned in any of these ways then it would be almost impossible that over an infinite amount of time and space, and possibly dimensions beyond our understanding, other universes did not also develop in a similar way.
For clarity, time and space are a representative idea in this description as they are used to articulate something outside our current universe and are therefore not actually time and space as we define those concepts.
A Plausible Framework
In all of these scenarios, it would seem highly plausible that universes are constantly being created and either surviving or collapsing. The “event” during which a universe is created establishes its foundation, or basic rules and constraints. This set of rules, likely including things like the speed of light, the cosmological constant, Planck lengths, and the Higgs field, could be different for each created universe. In some cases, the foundation would be unstable and the universe would instantly collapse or fail.
In other cases, the universe might survive a little longer before it collapses. In yet other cases the foundation might be right for the creation of stars, planets, and life. Lawrence Krauss gets at this in A Universe from Nothing by talking about cosmological natural selection: namely, that we live in a universe in which it is possible for intelligent organisms (us) to arise who can observationally verify that we live in a universe with the right conditions for intelligent organisms to arise.
So, here’s the basic framework of a plausible simulation theory:
- Universes have a starting point and are thus created by some event.
In all five of the precursor examples, the universe has a starting point. It is created in an event. (Even forks, although they are a lot weirder.)
Our current scientific understanding points to the Big Bang as the most likely event that spawned our universe. A large portion of the world population belives God(s) to be the progenitor of our particular universe, occasionally fused with a scientific explanation such as the Big Bang.
The framework of the Big Bang makes a viable starting point in all scenarios (in forks, only the original starting point could be viable in all scenarios). The God model only works in second-order scenarios.
2. Ours is not likely to be the only universe.
Not that long ago we believed there were no planets in our universe other than those in our solar system. Now we have found many. It seems that our desire for uniqueness does not reflect the realities of our environment. As discussed above, this also could be the case with our universe — it may not be unique.
Many religions imply this with concepts such as heaven, hell, and purgatory. As “places” it is implied that they must be outside our universe, meaning they must be in a different universe or that they are universes of their own. A universe could be an aspect of our universe in another dimension, i.e. parallel. The counterargument to this would be that they exist in dimensions that are incomprehensible or currently undiscovered in our universe.
3. If there is more than one universe, there are likely many universes.
If you look at planets or galaxies as a close corollary to universes, this would imply a near infinite number of universes. When counting something at this scale, the count is generally 1, 2, 3…infinity. So, referring to the previously discussed idea of planets, we used to believe only the ones we saw in our solar system existed.
Then we discovered a few. Now we are discovering new ones every day. We have now discovered that stars where we’ve detected a planet often turn out to be systems containing several planets and that stars lacking planets are the exception. This means that we can now state with confidence that there are more planets in the universe than stars.
While this is not a proxy for universes, it is the closest analog on which we have any observable data. Unfortunately, because other universes would primarily exist outside our observable space we are unlikely to be able to prove their existence. (There is some small chance that multiple universes could intersect in higher dimensions or be traversed in the fork scenario.)
4. A universe could, potentially, be created via technology. This means that a universe could be intentionally created then not all universes are accidents.
At first glance it would seem any technology that could create a universe would seem to require something akin to magic. But as Arthur C. Clarke’s third law says, “Any sufficiently advanced technology is indistinguishable from magic.” If we accept that there are many universes and universes have beginnings, a technological system for creating universes does not seem so far-fetched.
If the universe creation event is caused by a god or gods then the presumable path to this creation event is some form of technology. It is obviously technology that humankind cannot currently, and may never, understand, but it is technology nonetheless.
To ground that concept in our current reality, with today’s rapidly advancing technology it would take a significant leap forward in human progress to develop technologies that could create a new universe. However, there are scenarios that may be possible given the current trajectory of technical progress. Possibly even in the next century. There are two obvious places to look.
First, we could create small and most likely unstable universes in physical experiments using facilities such as CERN’s Large Hadron Collider. For now, we’re just looking for new particles and other dimensions. A universe created in this way would probably not be stable, but it would be easier for many to accept because it would be a physical creation.
Second, a simulated universe could be created in a massive supercomputer. The easiest to grasp, and the most likely initial experiments, would probably start with a model of the Big Bang and then be allowed to advance into the future could create a universe that was functionally autonomous. Some might argue this is not a real universe, but if life were to develop in such a universe it would be real to its inhabitants.
Barring some revelation by the creators of this simulation of their existence to the inhabitants in the simulation, the inhabitants would remain unaware and unsuspecting of the fact that they were participating in a simulation. Furthere, there would be no obvious way of testing whether they’re in a simulation. The rules that they developed to explain their reality would be consistent by definition — they reflect the rules of the simulation.
This is analogous to our inability to know whether there is anything outside our universe, or to test theories that attempt to address things outside of our universe. The inability of simulation inhabitants to know or to test whether they’re in a simulation renders this thought experiment about simulated universes an exercise that approaches pure philosophy that borders on religion. Again, all major religions inherently accept that we are a second-order universe and one created using technology, since they designate creator God(s) and often abstractly describe the creation event. This is the only logical model in which God(s) exist.
These are fun to think and speculate about, or to write a story about (read my sci-fi novel Accidental Gods).
But we can never know in effect because the only way to know is for the creators of the simulation to reveal themselves in some way to the inhabitants. In that way, it’s the same as religion and notions of God(s): god is unknowable and untestable, and the only way for us to know whether there’s a god is for it to reveal itself to us in some way.
Is a simulation possible?
There are two ways to think about how intelligent beings might exist in a simulation. One is the creation scenario, which assumes the universe is started from the beginning and allowed to run. In this approach the simulation begins with the Big Bang or a similar event in which the universe starts and it evolves from there, with or without further intervention.
The second simulation scenario is the immersion scenario, which assumes a much more constrained reality in which the simulation was created at a certain time, possibly with intelligent life, and is more of a window in time than an open-ended universe. There are many variations on the immersion scenario.
An intelligent being would be unlikely to be able to distinguish between these two scenarios any more than they would be able to recognize that they are living in a simulation at all.
Computing sophistication is rapidly advancing and modeling the Big Bang is certainly possible. However, it is currently not detailed enough to be considered a true simulation. Given current research and efforts, it seems like modeling the Big Bang would be the starting point from which humans could intentionally or accidentally go down the path of building a creation scenario simulation.
How long before we can let a simulated universe run long enough to see stars and galaxies form? For a functioning simulation this is a very large amount of data and computing power, so it is a big unknown. These requirements will, in part, be determined on what the reality level of that universe needs to be to enable a true simulation. It may be that at a certain depth, things will not “work” the same in the simulation.
For example, the simulation we create may be constrained in ways that affect the development of the universe and the ability of any intelligent life to either develop at all or to advance far enough that it is able to unlock the universe’s mysteries.
It could also be that there are computational restrictions on simulating a universe that make it inherently impossible.
The immersion scenario has been significantly explored in religion (literal creationists) and pop culture (The Matrix) and can be further divided roughly along those lines. A creationist model in which some higher-order being (god, gods) created a universe and populated it with intelligent life would presumably be an intelligently designed universe. The religious model would also include the creators revealing themselves. The most obvious way in which this type of universe might arise from ours is via games in which the internal characters become self-aware.
The forgotten model is a science fiction scenario that has reasonable viability given our current technological trajectory. In this model, a civilization creates a sufficiently advanced virtual reality, plugs in or uploads themselves to it, and forgets about their previous civilization and, thus, also forget they are in a simulation. This scenario could result from ennui, survival, or escapism.
From the science fiction point of view, this might take the form of simulations where humans can permanently upload or temporarily connect with shared simulations that are indistinguishable from reality. If, or when, this comes to pass, many may happily give up their corporeal form, or perhaps permanently store it in some form of hibernation, to live in these simulations.
This may be the biggest leap because it touches on the inherent arrogance of humanity. From the most basic creationist concepts to early scientific thought suggesting that every known object in the universe orbited the Earth, humans have a very human-centric view of their place in the universe. The “weak anthropic principle” is a tautology: only in a universe capable of supporting life can beings emerge capable of observing that they live in a universe capable of supporting life.
In spite of those viewpoints, humanity continues to push the art of the possible. Many experts in computer science and physics believe it will be possible to create very sophisticated simulations in the next century.
A significant amount of work on advanced simulations will focus on the Big Bang. It will be tempting to allow any such simulation to play out as long as possible. These simulations will also start with conditions similar to our own, since that will be what they attempt to model.
Whether there is enough computing power to keep a simulated universe running for billions of years (and how much real-time that will take) and whether those simulations are powerful enough to support the evolution of intelligent life are obviously a questions that are more difficult to answer.
Conclusion
While not easy, it is a straightforward path for humanity to create any number of possible simulated universes. Given that, it should also be possible that with the right framing and a little thought, to imagine a scenario where humanity, Earth, and our universe, are a simulation.
So if one accepts that we can reasonably expect to create a simulated universe and that there are many universes, it is almost certain we are not the first one. If we are not the first one, we are almost certain to be living in one given the enormous scale that must exist, extranal to our univere, to create universes like ours.
If we can create a simulated universe, statistics would dictate that we are in one.
In fact, virtually the only scenario in which we are not in a simulation is the one in which we are the first universe in which intelligent beings have developed. This is probably the most natural and easy belief system to accept for most people. Humanity, as previously stated, has a long history of very strong beliefs that it is both the first and the center of everything.
It is hard to dispel these beliefs given the proclivity of human nature and because there is an infinitesimally small chance that we can prove any of this given our frame of reference. But we are on a path to develop technology capable of creating a simulated universe. The chance that we are the first intelligent beings capable of achieving a simulated universe that is roughly equivalent to our own reality seems to be even smaller.
So if any sufficiently advanced intelligence can create a simulated universe, it is almost a certainty that we are living in one.
It’s turtles all the way down…
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NOTES
This is a thought experiment that I started developing in parallel to writing Accidental Gods in 2006. I primarily wrote that novel as a way to think about a scenario in which humans are the creators of a simulated universe.
It was my belief that fictional storytelling might make it easier for people to see how we might be living in a simulation. I felt like that was an interesting twist that would make an interesting story and might actually get a reasonable number of readers (I was wrong about that) over a drier, logic-oriented approach.
The original version of this was “Proof of God” because if we are in a simulation then there are god(s), at least in the creator sense of godhood, since a simulation by its nature necessitates an external intelligence, and probably more than one (most likely a civilization).
This is a developing concept and I welcome feedback. Thanks!
