Since reasoning became a thing, we’ve naturally begun to question everything. A big one in the philosophies is what “real” means and wether our senses can be trusted, and the ultimate outcome of that line of thinking is questioning if our reality is even “real” and whether we’re actually living inside a simulated virtual Universe. The “Matrix” movies are a classic representation of this idea, in their case run by a malevolent machine civilization farming humans for power.
More formally, I would like to approach this idea by exploring four questions relating to whether we’re inside a simulation:
- Is it physically possible?
- Why would someone simulate a Universe?
- Can any of our senses differentiate “real?”
- Does it even matter?
Is it physically possible?
Before we guess at the rest, we should determine whether a perfect-fidelity virtual existence is even possible within the laws of physics. Viktor T. Toth is one of the physicists I’ve learned the most from, who also relevantly happens to be an IT professional, and here’s what he had to say on the matter:
An efficient simulation requires a simulating computer that, at the very least, is not significantly larger, more complex, and slower than the system being simulated.
A system that involves quantum phenomena like those that we observe can only be simulated on a digital computer inefficiently: the digital computer would be countless orders of magnitude bigger, more complex, and slower than the system being simulated. (This is why we do not have good quality computer simulations of complex quantum systems such as larger molecules.)
To simulate our universe at the level of detail and consistency that we see, including detail and consistency at the level of quantum experiments, thus necessarily requires a quantum computer.
This is where my skepticism regarding scalable quantum computers comes in: I am of the opinion (I recognize that this is a minority opinion, and it is little more than a hunch; meanwhile, smart people are spending lots of money assuming the opposite) that scalable quantum computing is impossible for reasons of fundamental physics (i.e., not a technical limitation). If I am correct, then the computer that would simulate our universe at the level of fidelity that we see just cannot exist, in this or any other universe.
One possibility of course is that the fidelity is merely an illusion that is programmed into the simulation, but that doesn’t really work either, because to maintain self-consistency ends up in the end as a computational problem just as complex as a high-fidelity simulation in the first place.
Viktor T. Toth
Viktor makes some excellent points, but one thing not addressed is that inside a virtual world might the laws of physics themselves also be virtual? Constants such as the speed of light, gravity, Planck’s constant, etc. could all easily be arbitrary, could they not?
Additionally, I do agree with his overall premise that only a quantum computer (not a digital one) could simulate our Universe, however I’d add that it’s a 1:1 ratio – simulation at quantum fidelity requires equivalent quantum computational power, meaning to simulate a Universe you’d need a whole other Universe of quantum “servers,” much less digital servers.
This begs the question…
Why would someone simulate a Universe?
Nick Bostrom wrote an interesting paper on the possibilities of a simulated Universe in 2003. The key possible scenarios of the paper are as follows:
- Can’t Do It: Human-comparable civilizations are extremely unlikely to reach a level of technological maturity capable of producing simulated realities or such simulations are simply impossible to construct
- Won’t Do It: A civilization reaching post-human technological status is extremely unlikely to produce simulated realities for any of a number of reasons, such as diversion of processing power for other tasks, ethics, laws, simply uninterested, etc.
- Already In One: Any entities with our general set of experiences are almost certainly living in a simulation
- Not Invented Yet: We are still living in fundamental reality
Personally, I believe the truth is a bit of #1 – simulated realities are simply impossible to construct, but primarily #2 – a civilization so advanced would necessarily need an ethical structure superior to our own simply to exist: Destructive capacity scales with technological ability. If a civilization is so advanced it could create an entire reality on the quantum level with perfect fidelity, then its citizens need strong ethics to control their own power. If they didn’t have these ethics, the probability they’d destroy themselves is absurdly high.
Also, why bother? It’s arrogant to think such beings would find superior entertainment in watching humanity. Do gamers today prefer to play realistic virtual monkey life simulators? Or do they invent radical scenarios to push their imaginations with fancy laser weapons and sci-FI scenarios? Why would that concept be any different for a post-human civilization?
But for the sake of argument, let’s assume we’re all being simulated. Could we tell?
Can any of our senses differentiate “real?”
Harry Stottle over at The Ragged Trousered Philosopher wrote a great analogy addressing this question:
You are on a sandy beach blissfully sunning yourself. (Or, if you’re like some of us wary types, you’re hiding in the shade somewhere having become paranoid about skin cancer.) You can hear the gentle crashing of the waves on the nearby shore. You can smell the salt. You feel the heat. Shade or sun, its warm enough for you to be wearing a swim suit just within the bounds of early 21st conventions on decency. Beneath your beach blanket you are aware of the accommodating contour hugging of the fine sand.
Suddenly the idyllic afternoon is shattered. The beach wally turns up. Nowadays, of course, this usually means the antisocial nerd with a ghetto-blaster who parks himself 30 feet upwind and shares his love of obscure imported reggae or mind numbing heavy metal with the rest of the known universe. However, this is 50 years hence; things have moved on. His latest toy is a “Virtual Reality Sensory Transmitter” capable of transmitting apparently authentic signals direct to the optic nerves bypassing the retina of your eye. He tunes it with the usual gay abandon, and you suddenly realise that instead of a sandy beach, you can now see snow as far as the eye can see. You know what’s going on, of course, you’ve had this trouble before. In any case, all other senses confirm the status quo. You can still feel the warmth of the sun, hear and smell the sea nearby and feel the warm sand under the blanket. So you merely fume awhile till the pillock focuses the toy on some other victim. You know that the best way to escape his attention is to fane complete indifference – as though you can’t even perceive the machine’s effects.
On your next visit to the beach (obviously having failed to find a convenient “members only” private stretch where nerds are barred) you find yourself hit by a much more advanced version now capable of transmitting appropriate signals direct to all five sensory nerve pathways. This time, without warning, you find yourself lifted up and flown at incredible speed to the Arctic tundra and dumped down on an ice floe with a polar bear. And you’re still only wearing the swim suit! Its bloody freezing. The wind chill factor takes the temperature down to minus 40, The ice under your feet is excruciatingly cold and rather slippery. The bear is hungry and advancing towards you. What do you do?
Harry Stottle
This situation perfectly illustrates how our senses don’t care whether they’re being tricked, they perceive what they perceive. To them, we should RUN!
In fact, the only thing we can know with certainty is that we exist. How we exist is not guaranteed.
Does it even matter?
This is another great question concerning the simulated reality hypothesis, given how unverifiable it is. Should we even care? What is the value in knowing we’re in a simulation? Certainly, there seems to be more downside than upside in that knowledge, particularly given our realization that we’re in a simulation might end the simulation.
Jon Jermy over at Quora wrote a cute analogy on this subject:
Imagine that your friend comes up to you with a strange-looking bundle in his arms and announces: “I have a new pet!”
“What is it?” you ask.
“It’s a schnorf! They’re very rare. In fact, this is the only schnorf that anyone has ever seen!”
You admire the schnorf. “Well, it certainly is a strange little thing…”
“Of course!” says your friend, “You see, this schnorf is different to other schnorfs.”
You’re puzzled. “Wait a minute. I thought you said this was the only schnorf that anyone has ever seen.”
“Yes, that’s right.”
“Then how do you know it’s different from other schnorfs?”
“Well, it must be,” says your friend. “I mean, look at this. And that. Would other schnorfs have that?”
“I don’t see why not. After all, this schnorf has them.”
“But you can see from looking at it that it’s not like other schnorfs.”
“Not without looking at other schnorfs, I can’t.”
Your friend is in the same position as someone trying to claim that we are living in a ‘simulated’ universe. What this means — if it means anything at all — is that this universe is different in some way from other universes. But the only way to support that claim is to compare it with other universes, and since we have no access to other universes, that’s something we can’t do. Like your friend’s schnorf, this is the only universe we know anything about, and that makes it absurd for someone to claim that certain aspects of it are ‘strange’, or ‘special’, or ‘unlikely’.
Jon Jermy
Clearly the entire question of whether we live in a simulated reality is very complex. I suspect once we have our unified theory of physics and see more advances in virtual technology we’ll have better answers, but for now it’s just a fun thing to wonder about.