Like, is it possible that right now everything I am experiencing is a deception, like the Cartesian demon? Is that proposition intelligible, coherent and conceivable?

I think it is, and if it is, then it stands to reason that we might call that deception a “simulation”. So, crucially, simulations can recapitulate the phenomenal features we associate with ‘realness’. Dennett’s piece “Where am I?” also argues that simulations can deceive us into thinking they are ‘reality’, and some top notch VR experiences can simulate experiences we are not actually having with some fidelity.

Peter, you wrote:

“People do quite often set out a vision of the world as powered by maths; somewhere down there the fundamental equations are working away and the world is what they’re calculating.”

It’s by analogy- if the math that powers a convincing computer simulation is sufficient, then might it not stand to reaon by extrapolation that when I stop the VR headset and come back to “reality”, it’s actually just one more nested deception?

I don’t know if you’ve ever had the “dream within a dream” experience Peter, but *I have* and let me tell you it is extremely, extremely alarming and disconcerting when it happens.

The important thing to realize, I think, is that simulation-reality are not opposite words. All simulations, ultimately, are real in “some sense” since they must be executed by something that actually “exists”. I would also like to point out that the word “exist” is at the root of many tricky language issues in philosophy because it is a slippery and ambiguous word.

]]>The holographic principle (a theory of quantum-gravity), appears to be demonstrating that all of 3D space can be generated from a 2D boundary consisting of pure qubits (quantum information).

That’s really just a red herring, though. Every quantum mechanical system (of finite dimension) can trivially be described in terms of ‘pure qubits’—simply because all Hilbert spaces of the same dimension are isomorphic, and every finite-dimensional Hilbert space can be embedded within a space of dimension 2^n, i.e. an n-qubit Hilbert space; furthermore, every unitary (i.e. every possible time evolution) can be represented in terms of a finite set of qubit unitaries (this is what makes universal quantum computing possible). So, you could point to every quantum description as ‘evidence’ for an informational underpinning of physics.

And in fact, the same is true of Newtonian physics, and indeed, of any physical theory we might hope to formulate, at least in so far as we want to be able to compute anything within the theory, or simulate it—since then, the theory will be computable, and so, we can describe every system within the theory by means of a computational architecture. But just because we can describe everything this way, doesn’t mean things actually are this way—in just the same way, just because this message can be translated into bit strings doesn’t mean it is bit strings. It’s just confusing the map with the territory.

(Also, but that’s a whole different matter, calling the holographic principle a ‘theory’ of quantum gravity is a little premature—as of right now, it’s an unproven conjecture (albeit with a lot of evidence for it) that describes a universe we know isn’t ours, namely, a stationary one with constant negative curvature, rather than an expanding one with positive curvature.)

]]>Peter (17) and Tanju (19), Bostrom doesn’t just say this world might be a simulation (that would just be Cartesian skepticism warmed over), he says it probably is. And the reason is that in our world, we (supposedly) will create more simulated beings than non-simulated. So the physics of our world matters crucially to his argument.

]]>Black Hole Horizons” just has it that the entropy of a black hole can be shown equivalent to a quantum computer (Hayden-Preskill quantum circuit) of the appropriate number of qubits, and the complexity is the usual algorithmic run-time complexity, and ER=EPR (that is, quantum entanglement is via wormhole). Alice then tries to send a birthday message via an Einstein-Rosen Bridge to Bob who has fallen into a black hole. It all seems so simple when he explains it…

https://arxiv.org/pdf/1402.5674.pdf

“Clearly if the holographic entropy bound is correct then there is a large amount

of non-locality in whatever the correct theory of quantum gravity is. Indeed the area

scaling of the entropy led ‘t Hooft and Susskind to conjecture that a true theory of quantum gravity must in some sense live in one fewer dimensions than naively expected; Susskind called this idea the holographic principle.”

A lot depends on what kind of ‘information’ you’re talking about: Shannon information, meaningful information or whatever. Pure information sounds as if it exists in some eternal Platonic world, and this world doesn’t look like that to me! ]]>

So, what philosophy might sim beings develop and partake in?

]]>The idea actually has support coming from leading edge theoretical physics and empricial observations. The holographic principle (a theory of quantum-gravity), appears to be demonstrating that all of 3D space can be generated from a 2D boundary consisting of pure qubits (quantum information).

Top physicists including Sean Carroll, Leonard Susskind and others are now taking seriously the idea that ‘information’ is what is fundamental, and spacetime/gravity emerges from it.

https://phys.org/news/2017-01-reveals-substantial-evidence-holographic-universe.html

I think you need to keep an open mind here. Yes the idea that all of reality is pure information is deeply counter-intuitive, and on the surface does appear ridicious at first, but human intuition can be very very wrong.

]]>Bostrom says this world might be a simulation, so the simulation absolutely has to provide the physics Hossenfelder knows about.

What I meant is that if we are living in a simulation, the physics that we experience does not necessarily put any constraints of the physics of the (higher/parent) world in which our simulation is written and run. So the simulation provides (in fact, creates) our physics. The complexity we face in this world in dealing with this physics (say, quantum effects) does not imply a limitation on the capabilities of the simulator’s world. There is no way of deciding this question within our world. Sort of like a program running on a single core virtual machine cannot observe the multicore host it really is running on (provided there are no bugs in the supervisor 🙂

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