
Virtual Reality Poses the Same Riddles as the Cosmic Multiverse - pmcpinto
http://nautil.us/issue/46/balance/virtual-reality-poses-the-same-riddles-as-the-cosmic-multiverse?
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tryrall
This is not a very good article.

SF authors have explored these fascinating concepts without falling into such
holes in logic: such as presuming that a technology capable of simulating an
incomprehensible volume of intelligence was simultaneously too lazy to
leverage that intelligence to not cut corners in the simulation.

That said, I do subscribe to the school that says we must conclude one of the
following:

a) civilization in the abstract generally does _not_ progress to the point of
being able to simulate itself, or

b) we are the the first civilization ever, or

c) we are a simulation

~~~
bad_user
Given our experience with actual simulators, the fact is that simulating a
world populated with intelligent beings capable of simulating another world,
going into a recursive loop, requires _infinite processing capacity_.

My guess is that simulation indistinguishable from reality is never going to
happen because it isn't possible, having nothing to do with how evolved we
are.

~~~
visarga
The simulation doesn't have to run in full detail, there could be
approximations made far away from sentients. Also, the speed of the simulation
doesn't need to be 1:1.

~~~
ibgib
> _Also, the speed of the simulation doesn 't need to be 1:1._

This is what I think of when considering spacetime and relativistic effects.
If you think of "matter" as being equivalent to processing power required,
then the more processing required, the longer it takes to update the entire
frame. So other things with less matter are updated more quickly relative to
more massive segments.

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charles-salvia
> But if that’s the case, we run into a paradox. The argument for living in a
> simulation is based on the laws of physics and logic. But if we are living a
> simulation, we can’t trust those laws, so we have no basis to conclude we
> are living in a simulation.

This is borderline nonsensical. The "laws of logic" (i.e. law of identity/non-
contradiction, or propositional logic), are universal axioms that would not
change regardless of whether we're in a simulation or not. The "laws of
physics" could change, i.e. certain cosmological variables could be tweaked,
but this wouldn't affect our ability to reason about things like this.

~~~
stanfordkid
It's pretty simple: If you live inside the system and the system knows the
experiments you are conducting it can modify the "results" of these
experiments to fit a perceived set of axioms that hide the "true axioms".

Think of it like Geometric level of detail in video games: when the observer
is viewing a character from very far away a low-polygon mesh is displayed --
this is because the mesh only takes up a few pixels of screen space for the
observer so rendering a high polygon mesh or a low polygon mesh is
indistinguishable.

Now when the character is closer to the observer a high polygon mesh with more
detail is substituted.

The observer can never tell that this trick is happening. If they designed an
experiment to test for this the universe could simply spend more time fooling
the observer.

I am quite sure if we are living in a simulation it makes a lot of
approximations. When we conduct complex experiments it simply computes better
approximations so that our observed results fit the "axioms of physics".

~~~
ibgib
I like your video game view of mesh counts, and I assume you're also including
clipping as a special case of a 0-count mesh. And since we're programmers, I
think there is another very useful vocabulary to use when talking about this:
Eager vs lazy.

When I open a tree view, it doesn't have to eagerly evaluate all of the
contents of each node. It gives you the nodes that you are looking at and you
have a decision as to what you want to open. This is precisely analogous to
what you "pay attention to". So the "tricks" that you mention could be thought
of in terms of lazy evaluations.

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sixQuarks
What's amazing to me is that this question of a simulated reality would not
have even been possible to comprehend 150 years ago.

Without our understanding of computers, networks, and virtual reality, a
simulated universe theory would be very difficult to come about (not sure if
someone actually did theorize this back then, but even if they did, the vast
majority would have no idea what they were talking about).

That being said, what possibilities are we neglecting now due to our limited
knowledge? In 200 years, it may be obvious we're living in a totally different
type of universe.

In my opinion, we really won't have good idea of what kind of universe we're
living in for hundreds, if not thousands of years. There will be many cycles
of scientific consensus overthrown in the coming centuries as we discover new
layers of reality and technology.

~~~
charles-salvia
A Turing-machine based simulated reality certainly would have been
incomprehensible, but pre-20th century philosophers have thought about the
idea of the world not being "real" in some sense. I would even conjecture that
the universal experience of dreaming, and the fact that we often can't tell
when we're dreaming, would have probably inspired this line of thought going
back possibly even pre-homo sapiens.

Of course, Plato's cave is the most famous writing about the idea of a
"simulated" reality from antiquity, in the sense that it discusses the idea
that prisoners who spent their entire lives in a cave would assume that the
cave they see is the only reality.

~~~
tryrall
Indeed, what I find much more fascinating is that these ideas are not new at
all, but each generation frames it in a new technological light.

It's like how the brain used to be an ocean, then it was a windmill, then it
was a steam engine, then it was a computer, and now it's a GPU cloud. I wonder
what will come first: humans finally understanding what a brain is, or making
one.

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zitterbewegung
If we live in a simulated universe and cant tell that the universe is
simulated then what bearing does the question have when we can't answer it.
The person that wrote this article is conflating the idea of VR technology and
mixing it with the brain in a jar .

~~~
bjelkeman-again
Somewhat related, but isn't saying "we live in a simulation" just another way
to say "there is a god"?

~~~
charles-salvia
More or less yes - unless the simulation itself is auto-generated by some
other mindless program. (In which case we can eventually find God
recursively.)

~~~
diminish
or unless we are the ones running the simulation and enjoying the experience
of non virtual reality )

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cagenut
I have to assume this has been well trod elsewhere, but nothing that I've
seen, and this is the second or third recent HN article about the whole "maybe
we're in a simulation" thing, so I'm going to ask in good faith:

How is this not just... religion?

~~~
ZeroFries
If its a falsifiable claim its not religion. Supposedly its a falsifiable
claim.

~~~
beefield
How do you think that could be falsified? (Honest question, I have tried to
come up with a way to falsify this theory, but haven't figured out anythig.)

~~~
ZeroFries
[http://www.ijqf.org/wps/wp-
content/uploads/2017/03/IJQF-3888...](http://www.ijqf.org/wps/wp-
content/uploads/2017/03/IJQF-3888.pdf)

------
ibgib
> _any given person should rationally conclude he or she is made of ones and
> zeros rather than flesh and blood_

This statement presumes that "flesh and blood" are already not "ones and
zeros". It also relates to my view that the conflation of "information" and 1s
and 0s is very misleading. 1s and 0s are a view of information. The things on
my hard drive are not 1s and 0s, otherwise what would I call corrupted
locations?

------
ZeroFries
I dont understand the simulation argument. If I have a quantum computer, dont
I have to use at least N particles to simulate an N particle system? What am I
gaining by using a physical system to simulate a physical system?

~~~
charles-salvia
No you could use more coarse grained representations of distant objects or
less frequently observed objects. If our Universe is a simulation, for
example, given that the speed of information is limited, there's no reason to
completely simulate, say, whatever is happening in the Andromeda galaxy right
now. If we send an observer there, the simulation could just lazily produce
more fine-grained renderings.

~~~
dave_sullivan
Say you had a computer operating near planck scale (or some max bound on
physical density of a computer system), could you use that to represent more
information than would fit in the physical space?

The simulation argument is "If we ever create a simulation, we'll create more,
so we're probably in one of those simulations, unless we were first or are
unique at cosmic scales." Would lazy loading make it harder to simulate our
own universe at similar scales (harder to build a simulation in a simulation?)

At some point, unless we're living in a _limited_ simulation that can itself
not be fully simulated, aren't we getting something for nothing? And if it is
in fact limited, how do you show that?

Edit: basically what zerofries said...

~~~
charles-salvia
I think you're asking, if we took all the matter in the Universe and converted
it into a giant computer, would we be able to fully simulate our own Universe?

I think the answer is that if our Universe is currently, say, nested N levels
deep in a simulation hierarchy, the Universe we currently observe may appear
much more vast than it actually is, but since the speed of information is
limited, we could never prove this. So while the number of estimated atoms in
the observable Universe is something like 4×10^79, the actual number of
simulated particles may be far, far less. Certainly, the information that
comes to us via the light from distant galaxies is incredibly coarse grained
and time-lagged, and if we're in a simulation it may well be that no finer
grained representation actually exists (assuming there are no observers in
those galaxies).

I don't actually know if I believe the simulation argument, and all of this is
currently (perhaps forever) non-falsifiable. By the time we're able to even
send an observer to some distant galaxy ~5 billion light years away, the
Universe would have expanded even more, making the galaxy even further away.
But the limitations imposed on the speed of information via light cones seems
to make it very computationally feasible to simulate a Universe that appears
much larger and detailed than it actually is. So in other words, the
inhabitants of Universe at level N of the simulation hierarchy should be able
to simulate a lower-entropy _coarse approximation_ of their Universe at level
N + 1, that would be indistinguishable from Universe N to the simulated
inhabitants of N + 1, provided that sufficient restrictions on the speed of
information and the number of observers is enforced.

But intuitively it seems there should be a limitation here, in that as N
increases the level of nested computational resources available would need to
decrease, until you hit a low entropy "leaf Universe". But that doesn't really
affect the probabilistic angle of the simulation argument.

~~~
visarga
> if our Universe is currently, say, nested N levels deep in a simulation
> hierarchy

Maybe the simulation hierarchy is like a neural net - where hierarchy
represents more abstraction and meaning - the higher we go, the more exotic
the universes and more capable of carrying meaning by integrating information
from below. Such a neural-net hierarchical universe could be seen as "God".

~~~
ibgib
This is something that ibGib is a great tool for: understanding relationships
and "heirarchies", and understanding that a containment relationship is only
one way for viewing information. We find it easy to work with, since we're
used to files and folders. But the more I use ibGib, the more comfortable I am
with just having things related to each other.

This is precisely a neural network, and it's especially interesting when you
consider each person as a node in a larger network. You have your inputs and
your outputs and a bunch of layers sitting in between, i.e. you take an ANN,
draw a circle around it and connect it to other ANNs ad nauseam.

