Readers of my recent blog entry about how reality is in all probability a computer simulation are quite right to feel sceptical.

It's clearly a ridiculous notion, a clever bit of philosophical reasoning designed to invoke a paradox. Instinctively we know this. The Simulation Hypothesis goes against what we feel is the truth and as William of Occam himself carved with his famous Razor, the simplest explanation is usually the correct one. The original words of Occam's Razor are in fact particularly astute in this case; pluralitas non est ponenda sine necessitate or in plain English, plurality should not be posited without necessity. Why hypothesize a multitude of simulations when one simple reality will do?

It's just common sense.

However, common sense isn't always right. The ancients believed that the Earth was flat - and you can see why. It feels like common sense. Down is down - it's where things fall to. The ground is clearly flat and the sky "up there". If the world was a sphere, the people on the underside would fall off...

Don't trust common sense.

Of course I'm not claiming that the inaccuracy of the Flat Earth Theory means that the Simulation Hypothesis has to be true, just that things that feel wrong can sometimes be right. If this is a simulation how come I've been stuck in it for so long and why can't I be in a more interesting one where I'm out exploring the galaxy?

Well that's just it. Things are quite definitely not what they seem. As I have mentioned on more than one occasion before (or have I?) time is not necessarily linear. You might think you've been suffering and crying for slightly longer in the same old life but you may well have just arrived in your head five minutes ago with a full set of memories. There's no difference between that and actually living through your life so far. The seconds that make up your life span do not have to occur sequentially.

Maybe they don't even have to occur at all.

As discussed in Aping Reality it may simply be enough that the data comprising each instant is stored somewhere on the hard disk of the multiverse. After all if it doesn't matter in which order it is accessed then surely it doesn't actually need to be accessed. Every moment is preserved perfectly and unchanging in the lattice of reality storage. Its mere existence is enough to ensure yours.

And it doesn't even matter where it's stored.

Thought experiment! Thought experiment!

Think of the most powerful and complex computer ever devised by man. Perhaps it's not outlandish to imagine it simulating some kind of reality, albeit a simple one. Imagine a simple simulated human programmed into an artificial reality being run inside the Cray Jaguar. His name is Thugg2.0.

It could be that for all its mindboggling power, the Jaguar still isn't quite powerful to run Thugg2.0 at normal speed. In order to simulate him, to generate all of Thugg2.0's nerve impulses, his sensorium and his reactions, the Jaguar is forced to run Thugg2.0 at half speed. Ten seconds in the outside world is only five in Thugg2.0's world. Furthermore if Thugg2.0 decides to do something complicated - like scooping up a handful of sand and really concentrating on it as he lets it trickle through his fingers - the processing might slow even further, like an old 486 reaching the final level of Doom 2.

This won't affect Thugg 2.0. As far as he is concerned everything is continuing as normal, the speed of time in the outside world being a matter of supreme indifference to him.

Maybe cutbacks at the Oakridge National Laboratory mean that they can no longer justify taking up all the Cray Jaguar's runtime simulating Thugg2.0. However there are ethical considerations. They can't just switch him off. Instead they transfer his data and program to a smaller, slower computer called the Mini Cougar which can only run him at a maximum of a tenth normal speed.

Of course Thugg2.0 won't notice. Even if he has been provided with a data window into the outside world all he'll see is things out there apparently speeding up. Like an astronaut in a spacecraft approaching the speed of light or falling into a black hole he will have absolutely no sense whatsoever of his own time slowing down. Time is relative.

A global crisis means that even the Mini Cougar is considered a valuable asset and is commandeered by the government of the day. Thugg2.0 is transferred to a lashed together cluster of old dual-core Intel PCs running off a solar battery at the University of Utah. This can barely run him at a thousandth of the speed that the Mini Cougar could. An hour of Thugg2.0's time takes well over a year to run.

Thugg2.0 doesn't care. He's too busy scooping up handfuls of sand and really concentrating on them as he lets the grains trickle through his fingers. Whenever he does this, he observes, the events in the mysterious data window hanging in his sky lurch forward even faster.

One by one the old dual-core Intel PCs start to fail and are removed from the cluster until eventually Thugg2.0 is being run on just one of them. A minute of Thugg2.0's time now takes well over a century to process .

Thugg2.0 still doesn't notice even though he is now accelerating into the future at a speed approaching c.

The University of Utah is now an arcane temple in a post-apocalyptic world. The tending of the PC running Thugg2.0 is a religious ritual passed down from generation to generation. After a thousand years (or ten minutes as far as Thugg2.0 is concerned now) the computer breaks down.

The Monks of the Temple of Thugg2.0 face this crisis with equanimity. All the computer was doing was crunching numbers, they reason, so there's no reason they can't continue crunching these numbers themselves using abacuses, pencils and paper. They do so.

And Thugg2.0 doesn't notice.

After all there's nothing special or magical about the ancient hard disks and RAM in which the reality of Thugg2.0's existence is encoded in zeros and ones. All that is required to simulate Thugg2.0 is that the numbers are crunched. However slowly. It may now take a million years to simulate Thugg2.0 picking his nose and the calculations may now be stored as pencil marks on reams and reams of paper, but as far as Thugg2.0 is concerned he's just as real as he ever was even if the data window is now showing static.

An asteroid collides with Earth and wipes out the remains of humanity, including the Monks of the Temple of Thugg2.0. Since they first took over the job from the ailing computer, they've processed a fraction of a second, barely enough to even register to Thugg2.0.

Is this the end for Thugg2.0? Well, not necessarily. To use our relativity analogy he's reached the speed of light or has now fallen into the black hole - but he's not dead. Time has simply stopped for him. In fact as was pointed out earlier time need not be linear anyway, so maybe this state of affairs has made no appreciable difference to him whatsoever.

It's enough that the data comprising each instant of his existence is stored somewhere, and as we've just seen, the storage medium doesn't matter. These data instants don't have to follow on from each other in any way, they just have to exist. Somewhere and somewhen. As patterns of zeros and ones in a magnetic medium, on pieces of paper or perhaps as marks scratched in soot on the wall of a cave somewhere.

Or encoded in the structure of space-time itself?

Think of each data instant as a massive square array of zeros and ones, a multitude of yottapixels in digital camera terms. Now think about the multidimensional structure of the multiverse stretching in all directions of space, time and probability. All that was, is, will be or might have been. On a subatomic scale this could be described as granular and could be thought of as an infinitely large multidimensional matrix of zeros and ones.

Slice it just right and hey presto, there's Thugg2.0's next data instant, encoded just by chance in the very structure of reality itself - after all in an infinite multidimensional matrix every conceivable pattern of zeros and ones will occur. The Monks of the Temple of Thugg2.0 may have ceased working but all that is important is that the data is stored somewhere. Thugg2.0 carries on experiencing a sense of self.

And perhaps this is true for any sentient being you can imagine. If their data instants exist in a slice of multidimensional space-time, then so does their consciousness. In an infinite array, every pattern occurs. In the light of this, the distinction between whether something is "real" or a "simulation" becomes meaningless.

Your point of view all depends upon which way you slice the universe.


  1. dave W  

    Surely before you run a simulation you must have reality. Perhaps our previous lives (those that believe in them)were the simulation and we are now in the real life. i.e we've had our simulation even if you don't remember it. Which is actually more scary

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