The question “Do we live in a computer simulation?” was popularized in the move “The Matrix” and, as it turns out, not only is that a real possibility, but two University of Washington professors also say they can run a test to see if it is true.
In fact, it’s been a big couple of months for philosophers and scientists wondering if we live in a computer simulation.
Where it started
The question arose years ago by the philosopher Nick Bostrom in a paper titled “Are You Living In a Computer Simulation?” He wrote then:
“This paper argues 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.
It follows that the belief that there is a significant chance that we will one day become posthumans who run ancestor-simulations is false, unless we are currently living in a simulation.”
Basically, it’s likely this has happened unless we’re the first civilization in the first universe … you know, Ever! … which is pretty absurd. You can also hear Bostrom discuss his idea on the podcast Philosophy Bites.
So, we might just be in a computer
In the article published in November “Constraints on the Universe as a Numerical Simulation” the UW researchers said they had evidence we might be living in a simulation.
In lawman’s terms, according to the Huffington Post article on the announcement, this is what the researchers came up with:
“What that basically means is that by just being a simulation, the computer would put limits on, for instance, the energy that particles can have within the program.
“These limits would be experienced by those living within the sim – and as it turns out, something which looks just like these limits do in fact exist.”
Here’s how the researchers put it in the conclusion of their paper:
In this work, we have taken seriously the possibility that our universe is a numerical simulation. In particular, we have explored a number of observables that may reveal the underlying structure of a simulation performed with a rigid hyper-cubic space-time grid. …
Nevertheless, assuming that the universe is finite and therefore the resources of potential simulators are finite, then a volume containing a simulation will be finite and a lattice spacing must be non-zero, and therefore in principle there always remains the possibility for the simulated to discover the simulators.
UW professors want proof
The problem with running very complex simulations to test these theories is we currently do not have the computer power to do them. But, we may not need to run a super large simulation mirroring our universe to get to an answer.
UW professor Martin Savage and physics graduate student Zohreh Davoudi say they have come up with a method for testing whether this universe we call home is a simulation – even a simulation within a simulation.
Silas Beane, a researcher currently working in Germany, and the two from UW thought through the concepts this summer in Seattle. What they determined and then wrote in the paper “Constraints on the Universe as a Numerical Simulation” was that they can in theory see important signs in the simulations we can currently perform.
If they can find something like a limitation on energy in a small simulation, they should see it in a larger simulation and if they do and these are limits like the ones we see in our universe, then Bob’s your uncle we’re in a simulation.
Clarification: Savage corrected my understanding in the above sentence. He wrote in an email:
In our present day simulations in the very small volumes, we already see that particles have a maximum possible energy.
With finite computational resources, it will be the case that this is true in simulations of our universe performed by our descendents, of which we might be one.
The issue then becomes what is that maximum value and can we see it today in the spectrum of ultra high energy cosmic rays?
Update at 4:30: In a phone interview, Savage added that he and his colleagues wanted to make testable predictions about this idea that our universe could be a simulation … otherwise the concept remains a philosophical one. So, they needed something, a “signature,” that can be tested that would indicate we’re in a simulation.
They identified cosmic rays as having the potential to be that signature. Now it’s up to the scientists studying cosmic rays to find or not find constant limits in cosmic rays.
“These are mind blowing things I have to say, and we really know very little about it and our paper is the attempt to take it from philosophy to physics,” Savage said, adding “It would be really great if the UW had big supercomputers for us to be able to continue our simulation studies.”
Here’s how this concept was presented by UW in its article “Do we live in a computer simulation? UW researchers say idea can be tested”:
Currently, supercomputers using a technique called lattice quantum chromodynamics and starting from the fundamental physical laws that govern the universe can simulate only a very small portion of the universe, on the scale of one 100-trillionth of a meter, a little larger than the nucleus of an atom …
Eventually, more powerful simulations will be able to model on the scale of a molecule, then a cell and even a human being. But it will take many generations of growth in computing power to be able to simulate a large enough chunk of the universe to understand the constraints on physical processes that would indicate we are living in a computer model.
However, Savage said, there are signatures of resource constraints in present-day simulations that are likely to exist as well in simulations in the distant future, including the imprint of an underlying lattice if one is used to model the space-time continuum.
The supercomputers performing lattice quantum chromodynamics calculations essentially divide space-time into a four-dimensional grid. That allows researchers to examine what is called the strong force, one of the four fundamental forces of nature and the one that binds subatomic particles called quarks and gluons together into neutrons and protons at the core of atoms.
“If you make the simulations big enough, something like our universe should emerge,” Savage said. Then it would be a matter of looking for a “signature” in our universe that has an analog in the current small-scale simulations. …
If such a concept turned out to be reality, it would raise other possibilities as well. For example, Davoudi suggests that if our universe is a simulation, then those running it could be running other simulations as well, essentially creating other universes parallel to our own.
“Then the question is, ‘Can you communicate with those other universes if they are running on the same platform?’” she said.
The next question, even if we are living in a Martix like scenario, is “Does it matter?”