How Our Universe Being a Simulation Could Explain Quantum Mechanics

The most recent post over on the StarTalk board delves into the simulation hypothesis, what it means and how philosophers and physicists have tried to untangle the puzzle.

But one thought stuck with me: doesn’t the simulation hypothesis kind of explain the weird stuff about quantum mechanics?

This wasn’t an original idea – in fact, there’s a great paper that covers these issues and even proposes some tests.

The Problems with Simulating a Universe

Bostrom's original paper introduces the concepts of the simulation hypothesis, but brushes over a key issue. He speaks of “posthuman” societies with planet-sized computers, but later authors generally pay more attention to the limitations. No matter how big the computer, the processing power is still finite.

Campbell et. al. [2] compare this to rendering a computer game. Most designers don’t render the whole map all the time – you really only need it to render what the player can see. Taking this shortcut maximizes the usable output from your limited computing capability. It’s efficient.

And if you were simulating a universe – especially ones that could contain simulations themselves – efficiency would be crucial. You’re unlikely to have a definitive plan for every electron, through the whole history of the universe.

What This Could Explain About Quantum Mechanics

• The program “plays dice”: Why is quantum mechanics probabilistic? Because like No Man’s Sky or the Binding of Isaac, the generation of the universe is procedural. Simply calculating as needed based on some probabilities would save computing power.

• Wavefunction collapse: When we make an observation of the quantum world, we’re taught that the many possibilities of the initial wavefunction “collapse” to a single result, but nobody knows why. The simulation hypothesis explains this easily: the precise value would only be “rendered” when we look at it. The strange behaviour is because the simulation finally settles on one possibility when we look.

• Quantum entanglement: How do we get “spooky action at a distance” aka quantum entanglement? It’s weird that information can apparently travel faster than light, unless it’s a simulation. Then the information may not travel that far at all – it’s all in the same computer, after all.

But, as Terence Tao pointed out on the podcast, if reality is a simulation, it’s incredibly – suspiciously – consistent. 

Season 17, Episode 12: Are We Living in a Simulation?

Hey StarTalkers! Season 17, episode 12 sees Neil and Paul go through some cosmic queries with legendary mathematician Terence Tao. A reader question near the end of the episode opens up a potentially huge discussion: Do we live in a simulation?

Is the Universe a Math Problem? With Terence Tao - StarTalk Radio

(starts at 49:30)

They discuss the idea for a few minutes – and it’s been covered on StarTalk before – but as always with these “cosmic queries” discussions, there isn’t much time to go into detail.

So, what exactly is simulation theory and why do so many people seem to believe it? Let’s dig in.

Bostrom’s Paper

The modern form of the simulation hypothesis comes from a 2003 paper by Nick Bostrom .

First, he argues that it should be possible to simulate consciousness. Bostrom is talking sci-fi more than “real life,” rooted in known science but pushed to the extreme. If we had a computer the size of a planet, he concludes that we could simulate “the entire mental history of mankind.”

In other words, we could simulate every human brain to ever exist.

The Three Possibilities

This leads to three possibilities:

1. No human-level civilizations reach this technological level. Either large-scale disaster (man-made or not) or technological stagnation could prevent this from happening.

2. No human-level civilization at this tech level is interested in making such simulations. After developing to this level, human-level civilizations could simply lose interest in making these simulations. Maybe they’re too advanced to benefit, or think it’s cruel to simulate human-like minds.

3. We are almost certainly living in a simulation. If 1) and 2) aren’t true, then it’s likely there are many simulations. If there are simulations within simulations, the number becomes truly huge (see image below). At this point, a simple count of “real” vs. simulated realities makes it almost certain we’re in a simulation.

Improving the Estimate

Bostrom basically compares numbers (real vs. simulated) to make his famous argument. But there’s a slightly improved, Bayesian calculation that just puts us at just over 50% odds of living in a true reality. One key difference is assuming some limit to simulations within simulations – eventually, computing power runs out.

So toss a coin. If you call it right, maybe we’re real.