My brain tells me this:

1. Real (1 entity)

2. Real + Simulation (2 entities)

Which is simpler?

The novacula Occami: Do not multiply entities without necessity.

Does the world as real suffice as an explanatory framework
for all phenomena or is there something that's inexplicable about what we see around us which necessitates the simulation hypothesis?

As for solipsism, it is simpler - only one person viz. yourself hasta be real instead of 6,999,999,999 others..

A tension now builds - I don't know how to defuse it.

A thousand apologies. — Ranjeet

This is an attack on all theories in the vein of the recently fashionable "The universe is a simulation": — hypericin

I do not think the universe is a simulation. But I do think it is a kind of computing system.

In computer science it is known that it takes more computational power to simulate a computer system than the computer system itself has; typically, much more. I think this principle can be generalized:

For any system S, any complete simulation of S, S', must be more more complex than S — hypericin

I think this is true if one assumes that the simulation is of the exact quality and complexity of the universe the computer making the simulation belongs to. I don't think it's so if the computer is aiming to simulate a simpler type of universe than the universe the computer is in.

I would assume entities in the simulation would not be able to tell any difference within their own simulated reality, and they wouldn't be able to compare their computed reality with the computing reality. If these simulated entities decided to create their own simulated reality, it would have to be even simpler than theirs too.

One way i think the computing limitations can be overcome is by simply extending the time the computer needs to calculate the next time step. For the entities in that simulation time would feel as if it were running normally. Since each simulated entity is computed together with the rest of the simulation, they experience things in time with the simulation. Meaning that from one time step to the next, no matter how long it takes to calculate that time step, the entities would perceive it as instantaneous. The speed of "light" in their universe would probably need to be slower than in the computing universe to compensate for the difference in computing speed, but it wouldn't feel any different to them. This is all mostly speculation of course.

I think this is true if one assumes that the simulation is of the exact quality and complexity of the universe the computer making the simulation belongs to. — punos

You seem to be answering the argument, "How can a computer be so powerful as to simulate the whole universe, when the computer is a part of the universe?" I am not making that argument.

As for solipsism, it is simpler — Agent Smith

Solipsism implies a vastly more powerful brain than what you believe you have, as 99.9999999999.... % of it is unconscious: the part that remembers everything, so that everything is consistent, every time you check it, the part that simulates every physical phenomenon to perfect exactitude, the part that knows the entirety of every science and art, etc. etc. etc.

Where does this brain live? In this universe, or are we supposing a new one? How does it operate? Are you a dreaming god? Then what is the physics of the waking universe?

@hypericin

Possible, quite possible. Many philosophical ideas are the kind that philosophers haven't really explored in earnest - the mere possibility of some scenario makes philosophers all soooo excited. I'm not saying this is bad, but à la an old forum member, it ain't good either.

Well yes, but like i said, only if it's trying to simulate it's own universe at the exact resolution of it's own universe.

As for solipsism — Agent Smith

When we sleep and we dream, isn't the mind creating a simulation of a universe? We even take it as actual reality, except if you are lucid dreaming. This also applies to the idea of solipsism, where the entire dream is one persons mind, but with seemingly independent characters populating it. How do we know that this reality is not of the same nature as a dream reality? Maybe the nature of any and every reality is of the nature of dreams. Again... speculation speculation.

Doubting Thomas!

Doubting Thomas! — Agent Smith

Doubting Thomas was the only disciple to ever touch the resurrected body of Christ. His doubt earned him that privilege.

Does your OP assume that the simulation has to simulate everything? Can't it just simulate parts of it, making it seem as if the whole thing is simulated? In other words, the simulation only needs to simulate "appearances" not the thing-in-itself.

Yup! I didn't say anything, but I think this is the fatal flaw in my argument. You only have to simulate enough to fool the sentient beings, and our brains really aren't that powerful, so you might wind up with large savings in complexity.

True, you have to account for whatever universe the simulator lives in. But this might be much smaller, and less complex, than the universe the simulator portrays.

So then, by the logic of the op, how do we avoid the absurd conclusion of always preferring the simulation theory?

For any system S, any complete simulation of S, S', must be more more complex than S — hypericin

Agree, but a virtual reality (BIV) only needs to provide one artificial feed of experience to the experiencer in the vat, so to speak. It doesn't require an inordinate amount of resources. I'm not suggesting I support such a view, but the complexity argument doesn't seem to shoot this one down directly.

Most of the Brain-in-Vat theorists presume that the experiencer is somehow still a brain (a pink wet gloppy thing with some wires). There is zero evidence of that. There is zero evidence of anything for that matter if the experience it is being fed is all lies.

You seem to be answering the argument, "How can a computer be so powerful as to simulate the whole universe, when the computer is a part of the universe?" I am not making that argument.

This is apparently about an actual simulation (as opposed to a VR premise), and it presumes that the simulation is being performed by a universe with the same rules as the one being simulated. There's no reason to assume that since there's no evidence for it.

I mean, our physics can be simulated at best down to the classical level, not the quantum level. To do that, you need something with more capability, with completely different rules.

You only have to simulate enough to fool the sentient beings — hypericin

How would a physics simulation know when a particular state of simulated material qualifies as a sentient being requiring being fooled? It means the physics must change depending on what is measuring it.

It doesn't require an inordinate amount of resources. — noAxioms

It's an interesting thought experiment to consider the complexity required to simulate one person's experience with perfect fidelity and consistency, vs the complexity of the whole planet. In a traditional computer simulation, computational power increases exponentially with increasing fidelity, a perfect holodeck style simulation will never be achieved (famous last words, but...)

I mean, our physics can be simulated at best down to the classical level, not the quantum level. To do that, you need something with more capability, with completely different rules. — noAxioms

But still the simulation theory presumes all the complexity of the actual would, the simulation of it, and the universe with different rules hosting that simulation. Whatever that universe's laws, the simulation theory presumes far more complexity than the non-simulation theory.

How would a physics simulation know when a particular state of simulated material qualifies as a sentient being requiring being fooled? — noAxioms

I was assuming that the "subjects" are the only sentient ones, and that simulated entities are all p-zombies. It gets quite a bit trickier if these agents develop sentience on their own!

Putnam's BIVs are about meaning and not a suggestion about how a simulation would look like or even suggestive of that as a possibility. I think the question "are we living in a simulation?" is moot. If we live in a simulation our reality is simulated and our ideas about things refer to simulated things. Doesn't make our experiences any less real though. And since there's no "really real" to meaningfully talk about (all we have is concepts of simulated things), then the existence of the really real is irrelevant and so is the nature of our reality. It's all we know and can know.

Solipsism implies a vastly more powerful brain than what you believe you have, as 99.9999999999.... % of it is unconscious: the part that remembers everything, so that everything is consistent, every time you check it, the part that simulates every physical phenomenon to perfect exactitude, the part that knows the entirety of every science and art, etc. etc. etc. — hypericin

Or it just seems consistant. There's a built in, this is correctly connected to the past quale. That shouldn't require something more powerful than our unconscious, just something different. Also the OR is about how many entities are posited.

In computer science it is known that it takes more computational power to simulate a computer system than the computer system itself has; typically, much more. — hypericin

Is this true? Do you have a source for that statement? Seems to me if I could create a perfect copy of the universe, it would be a complete analog simulation of the original and would be no more complex.

that would be no more a simulation of the universe than an iPhone is a simulation of an iPhone

that would be no more a simulation of the universe than an iPhone is a simulation of an iPhone — hypericin

A simulation imitates the operation of real world processes or systems with the use of models. The model represents the key behaviours and characteristics of the selected process or system while the simulation represents how the model evolves under different conditions over time. — TWI

You can't get any better model of something than an artificial copy of it.

In computer science it is known that it takes more computational power to simulate a computer system than the computer system itself has; typically, much more. I think this principle can be generalized: — hypericin

This isn't exactly true or useful. While it does take more power to emulate a system, you can fully emulate an older system on a more powerful system. Just look at MAME the Multiple Arcade Machine Emulator that emulates vintage arcade machines and vintage home computers and consoles.

Emulating the the system that you are currently using on the same system is pointless.

While it does take more power to emulate a system, you can fully emulate an older system on a more powerful system. Just look at MAME the Multiple Arcade Machine Emulator — Harry Hindu

I'm quite familiar. Exactly how does this contradict what I said?

You can't get any better model of something than an artificial copy of it. — T Clark

The quote referring to abstract simulations. They abstract relevant features into a model, and simulate the model. I'm referring to complete simulation, also called emulation. If you have two identical things, one is not emulating the other. Simulation/emulation refer to something else: one system arranged to duplicate the behavior of another.

Exactly how does this contradict what I said? — hypericin

As I pointed out, all you need is a more powerful information processing system to simulate another system that has less information. Your argument is invalid because you dont know if our universe contains all possible information. You just dont know how much information actually exists. Our universe could be a fraction of the total information so a larger system could actually be simulating our universe.

My brain tells me this:

1. Real (1 entity)

2. Real + Simulation (2 entities) — Agent Smith

Invalid if we think of the simulation as part of reality. All simulations exist within one reality. Simulating an old gaming console on your modern computer is real example of a simulation within reality. Both the simulator and the simulation are only a fraction of reality. The problem is that we just don't know how big reality is, or how much information exists.

Invalid if we think of the simulation as part of reality. All simulations exist within one reality. Simulating an old gaming console on your modern computer is real example of a simulation within reality. Both the simulator and the simulation are only a fraction of reality. The problem is that we just don't know how big reality is, or how much information exists. — Harry Hindu

I humbly disagree.

A simulation’s an additional entity over and above reality.

A simulation’s an additional entity over and above reality. — Agent Smith

No. It's not. A simulation exists within reality as it is composed of real things. You need a real computer to create a simulated one.

I have no idea what "over and above reality" means anyway. Reality is all there is. There can be no "over and above" reality.

There is reality and then there is the simulation. I count two "entities"; how many do you see?

It's true that the simulation is part of reality, within it to be precise. However, the simulation is a world unto itself and so must be treated as equals with the world it is within.

It's true that the simulation is part of reality, within it to be precise. However, the simulation is a world unto itself and so must be treated as equals with the world it is within. — Agent Smith

:roll:

Let's discuss the point further. You say that a simulation is part of (some) real world. I concur.

However, this hypothesis entails the existence of 2 worlds: the real + the simulation (within that world). Compare that to the belief that this which we experience is real (only 1 world). How would William of Occam tackle this?

How would William of Occam tackle this? — Agent Smith

By understanding that if a simulation is a world it is no longer a simulation. A simulation only makes sense in light of a world.

Is a map of the territory another "territory"? Just because the map does not represent itself on the map even though it is part of the territory does not mean that it is above and beyond the territory. It just means that it would be useless to do so.