Comment by A_D_E_P_T | Hacker News Reader

Comment by A_D_E_P_T | Hacker News Reader

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Oh man, Stephen Wolfram and Jürgen Schmidthuber are probably fuming at the fact that this is called a "new" mathematical framework. It's all very old, and quite conventional, even popular -- not exactly the road not taken.

What the author did was use the Physical Church-Turing thesis, and Kleene's second recursion theorem, to show that: (1) If a universe’s dynamics are computable (PCT), and (2) the universe can implement universal computation (RPCT), then (3) the universe can simulate itself, including the computer doing the simulating.

That's basically all. And thus "there would be two identical instances of us, both equally 'real'." (Two numerically distinct processes are empirically identical if they are indistinguishable. You might remember this sort of thing from late 20th c. philosophy coursework.)

He also uses Rice’s theorem (old) to show that there is no uniform measure over the set of "possible universes."

It's all very interesting, but it's more a review article than a "new mathematical framework." The notion of a mathematical/simulated universe is as old as Pythagoras (~550 BC), and Rice, Church-Turing, and Kleene are all approaching the 100-year mark.

I'm no mathematician, but doesn't this come up against Gödel's incompleteness theorem? My brain has that roughly as "If you have a system and a model of that system, but the model is also part of the same system, something something, impossible"

Isn't GIT you can have a statement that is valid in a system, but can't be proven this way or that given the systems' axioms? And this is true for all such axiom systems? In other words the axioms are an incomplete description of the system.

Maybe the problem is axiomative deduction, we need a new inference-ology?

No, this sort of self-reflection is exactly what makes Gödel/Turing/etc impossibility results work ("strange loops" and all that).

Can you explain further?

Maybe I'm too out of this scope but if you want to simulate Universe X plus the computer Y that simulates X then you'd need at least 1 extra bit of memory (likely way more) to encompass the simulation plus the computation running the simulation (X+Y). The computer running the simulation by definition is not part of the simulation, so how can it be that it can truly simulate itself?

In Men in Black II (2002), Will Smith learned that a miniature civilization existed in a locker. Later, Will Smith’s character learned that our civilization was in a locker of a larger civilization.

By thinking of memory usage, you’re restricting yourself to our perceived physical limits withine our perceived reality.

But, what if the things running the simulation did not have those limits? E.g. maybe data could be stored in an infinite number of multiverses outside of the infinite simulations being discussed. Any of the simulations could potentially simulate universes like ours while still allowing those simulations to contain others, to be contained by others, to have references to others, to have reflective references, etc. The makes anything and everything possible while not necessarily removing limits we have in our own simulation. It just depends on what’s running the simulation.

Not quite, compression enables you to simulate / represent / encode x data with less than x memory.

Only for those inputs that are compressible.

If a compressor can compress every input of length N bits into fewer than N bits, then at least 2 of the 2^N possible inputs have the same output. Thus there cannot exist a universal compressor.

Modify as desired for fractional bits. The essential argument is the same.

Would the compressibility of the state of the universe be useful to prove whether we are in a simulation already? (i.e. it is hard to compress data that is already compressed)

Roughly speaking, Gödel encoded (or “simulated”) the formal part of mathematics within arithmetic (using operations such as addition and multiplication), and constructed a sentence that says “this sentence is unprovable” within that simulation.

Godel's incompleteness theorem is about the limits of proof / mathematical knowledge. Algebra is still useful and true, even though the proof shows it must be incomplete.

Any decent Lisp can reimplement eval, apply and the rest of functions/atom within itself.

It’s also a little silly for the same reasons discussions of theoretical computability often are: time and space requirements. In practice the Universe, even if computable, is so complex that simulating it would require far more compute than physical particles and far more time than remaining until heat death.

Hehe yeah.. For me, its just inverted search for the God. There must be somethink behind it, if its not God, then it must be simulation! Kinda sad, I would expect more from scientist.

The big riddle of Universe is, how all that matter loves to organize itself, from basic particles to Atoms, basic molecues, structured molecues, things and finally live.. Probably unsolvable, but that doesnt mean we shouldnt research and ask questions...

>The big riddle of Universe is, how all that matter loves to organize itself, from basic particles to Atoms, basic molecues, structured molecues, things and finally live.. Probably unsolvable, but that doesnt mean we shouldnt research and ask questions...

Isn't that 'just' the laws of nature + the 2nd law of thermodynamics? Life is the ultimate increaser of entropy, because for all the order we create we just create more disorder.

Conway's game of life has very simple rules (laws of nature) and it ends up very complex. The universe doing the same thing with much more complicated rules seems pretty natural.

Yeah, agreed. The actual real riddle is consciousness. Why does it seems some configurations of this matter and energy zap into existence something that actually (allegedly) did not exist in its prior configuration.

I'd argue that it's not that complicated. That if something meets the below five criteria, we must accept that it is conscious:

(1) It maintains a persisting internal model of an environment, updated from ongoing input.

(2) It maintains a persisting internal model of its own body or vehicle as bounded and situated in that environment.

(3) It possesses a memory that binds past and present into a single temporally extended self-model.

(4) It uses these models with self-derived agency to generate and evaluate counterfactuals: Predictions of alternative futures under alternative actions. (i.e. a general predictive function.)

(5) It has control channels through which those evaluations shape its future trajectories in ways that are not trivially reducible to a fixed reflex table.

This would also indicate that Boltzmann Brains are not conscious -- so it's no surprise that we're not Boltzmann Brains, which would otherwise be very surprising -- and that P-Zombies are impossible by definition. I've been working on a book about this for the past three years...

If you remove the terms "self", "agency", and "trivially reducible", it seems to me that a classical robot/game AI planning algorithm, which no one thinks is conscious, matches these criteria.

How do you define these terms without begging the question?

If anything has, minimally, a robust spatiotemporal sense of itself, and can project that sense forward to evaluate future outcomes, then it has a robust "self."

What this requires is a persistent internal model of: (A) what counts as its own body/actuators/sensors (a maintained self–world boundary), (B) what counts as its history in time (a sense of temporal continuity), and (C) what actions it can take (degrees of freedom, i.e. the future branch space), all of which are continuously used to regulate behavior under genuine epistemic uncertainty. When (C) is robust, abstraction and generalization fall out naturally. This is, in essence, sapience.

By "not trivially reducible," I don't mean "not representable in principle." I mean that, at the system's own operative state/action abstraction, its behavior is not equivalent to executing a fixed policy or static lookup table. It must actually perform predictive modeling and counterfactual evaluation; collapsing it to a reflex table would destroy the very capacities above. (It's true that with an astronomically large table you can "look up" anything -- but that move makes the notion of explanation vacuous.)

Many robots and AIs implement pieces of this pipeline (state estimation, planning, world models,) but current deployed systems generally lack a robust, continuously updated self-model with temporally deep, globally integrated counterfactual control in this sense.

If you want to simplify it a bit, you could just say that you need a robust and bounded spatial-temporal sense, coupled to the ability to generalize from that sense.

> so it's no surprise that we're not Boltzmann Brains

I think I agree you've excluded them from the definition, but I don't see why that has an impact on likelihood.

I don't think any of these need to lead to qualia for any obvious reason. It could be a p-zombie why not.

The zombie intuition comes from treating qualia as an "add-on" rather than as the internal presentation of a self-model.

"P-zombie" is not a coherent leftover possibility once you fix the full physical structure. If a system has the full self-model (temporal-spatial sense) / world-model / memory binding / counterfactual evaluator / control loop, then that structure is what having experience amounts to (no extra ingredient need be added or subtracted).

I hope I don't later get accused of plagiarizing myself, but let's embark on a thought experiment. Imagine a bitter, toxic alkaloid that does not taste bitter. Suppose ingestion produces no distinctive local sensation at all – no taste, no burn, no nausea. The only "response" is some silent parameter in the nervous system adjusting itself, without crossing the threshold of conscious salience. There are such cases: Damaged nociception, anosmia, people congenitally insensitive to pain. In every such case, genetic fitness is slashed. The organism does not reliably avoid harm.

Now imagine a different design. You are a posthuman entity whose organic surface has been gradually replaced. Instead of a tongue, you carry an in‑line sensor which performs a spectral analysis of whatever you take in. When something toxic is detected, a red symbol flashes in your field of vision: “TOXIC -- DO NOT INGEST.” That visual event is a quale. It has a minimally structured phenomenal character -- colored, localized, bound to alarm -- and it stands in for what once was bitterness.

We can push this further. Instead of a visual alert, perhaps your motor system simply locks your arm; perhaps your global workspace is flooded with a gray, oppressive feeling; perhaps a sharp auditory tone sounds in your private inner ear. Each variant is still a mode of felt response to sensory information. Here's what I'm getting at with this: There is no way for a conscious creature to register and use risky input without some structure of "what it is like" coming along for the ride.

I have more or less the same views, although I can’t formulate them half as well as you do. I would have to think more in depth about those conditions that you highlighted in the GP; I’d read a book elaborating on it.

I’ve heard a similar thought experiment to your bitterness one from Keith Frankish: You have the choice between two anesthetics. The first one suppresses your pain quale, meaning that you won’t _feel_ any pain at all. But it won’t suppress your external response: you will scream, kick, shout, and do whatever you would have done without any anesthetic. The second one is the opposite: it suppresses all the external symptoms of pain. You won’t budge, you’ll be sitting quiet and still as some hypothetical highly painful surgical procedure is performed on you. But you will feel the pain quale completely, it will all still be there.

I like it because it highlights the tension in the supposed platonic essence of qualia. We can’t possibly imagine how either of these two drugs could be manufactured, or what it would feel like.

Would you classify your view as some version of materialism? Is it reductionist? I’m still trying to grasp all the terminology, sometimes it feels there’s more labels than actual perspectives.

> The zombie intuition comes from treating qualia as an "add-on" rather than as the internal presentation of a self-model.

Haven't you sort of smuggled a divide back into the discussion? You say "internal presentation" as though an internal or external can be constructed in the first place without the presumption of a divided off world, the external world of material and the internal one of qualia. I agree with the concept of making the quale and the material event the same thing, (isn't that kinda like Nietzsche's wills to power?), but I'm not sure that's what you're trying to say because you're adding a lot of stuff on top.

That is not what a p-zombie is. The p-zombie does not have any qualia at all. If you want to deny the existence of qualia, that's one way a few philosophers have gone (Dennett), but that seems pretty ridiculous to most people.

You're offering a dichotomy:

1. Qualia exist as something separate from functional structure (so p-zombies are conceivable)

2. Qualia don't exist at all (Dennett-style eliminativism)

But I say that there is a third position: Qualia exist, but they are the internal presentation of a sufficiently complex self-model/world-model structure. They're not an additional ingredient that could be present or absent while the functional organization stays fixed.

To return to the posthuman thought experiment, I'm not saying the posthuman has no qualia, I'm saying the red "TOXIC" warning is qualia. It has phenomenal character. The point is that any system that satisfies certain criteria and registers information must do so as some phenomenal presentation or other. The structure doesn't generate qualia as a separate byproduct; the structure operating is the experience.

A p-zombie is only conceivable if qualia are ontologically detachable, but they're not. You can't have a physicalism which stands on its own two feet and have p-zombies at the same time.

Also, it's a fundamentally silly and childish notion. "What if everything behaves exactly as if conscious -- and is functionally analogous to a conscious agent -- but secretly isn't?" is hardly different from "couldn't something be H2O without being water?," "what if the universe was created last Thursday with false memories?," or "what if only I'm real?" These are dead-end questions. Like 14-year-old-stoner philosophy: "what if your red is ackshuallly my blue?!" The so-called "hard problem" either evaporates in the light of a rigorous structural physicalism, or it's just another silly dead-end.

You have first-person knowledge of qualia. I'm not really sure how you could deny that without claiming that qualia doesn't exist. You're claiming some middle ground here that I think almost all philosophers and neuroscientists would reject (on both sides).

> "couldn't something be H2O without being water?," "what if the universe was created last Thursday with false memories?," or "what if only I'm real?" These are dead-end questions. Like 14-year-old-stoner philosophy: "what if your red is ackshuallly my blue?!"

These are all legitimate philosophical problems, Kripke definitively solved the first one in the 1970s in Naming and Necessity. You should try to be more humble about subjects which you clearly haven't read enough about. Read the Mary's room argument.

> You have first-person knowledge of qualia. I’m not sure how you could deny that...

I don't deny that. I explicitly rely on it. You must have misunderstood... My claim is not:

1) "There are no qualia"

2) "Qualia are an illusion / do not exist"

My claim is: First-person acquaintance does not license treating qualia as ontologically detachable from the physical/functional. I reject the idea that experience is a free-floating metaphysical remainder that can be subtracted while everything else stays fixed. At root it's simply a necessary form of internally presented, salience-weighted feedback.

> This middle ground would be rejected by almost all philosophers and neuroscientists

I admit that it would be rejected by dualists and epiphenomenalists, but that's hardly "almost all."

As for Mary and her room: As you know, the thought experiment is about epistemology. At most it shows that knowing all third-person facts doesn’t give you first-person acquaintance. It is of little relevance, and as a "refutation" of physicalism it's very poor.

Is there a working title or some way to follow for updates?

There is no objective evidence consciousness exists as distinct from an information process.

There is no objective evidence of anything at all.

It all gets filtered through consciousness.

"Objectivity" really means a collection of organisms having (mostly) the same subjective experiences, and building the same models, given the same stimuli.

Given that less intelligent organisms build simpler models with poorer abstractions and less predictive power, it's very naive to assume that our model-making systems aren't similarly crippled in ways we can't understand.

Or imagine.

That's a hypothesis but the alternate hypothesis that consciousness is not well defined is equally valid at this point. Occam's razor suggests consciousness doesn't exist since it isn't necessary and isn't even mathematically or physically definable.

For me the biggest riddle is: why something instead of nothing ?

That's the question that prevent me from being atheist and shift me to agnosticism.

There is both in superposition.

> The big riddle of Universe is, how

A lot of people are more interested in the Why of the Universe than the How, though.

How is an implementation detail, Why is "profound". At least that's how I think most people look at it.

Yeah I guess... But such question is not really intereseting.. Answer is simple, there is nothing behind it.. and people arent confortable with that answer. Hence "How" is more interesting and scientific..

You expect scientists to not ask :‘what is behind all this?’

Ha

Yes, is that (obvious) point being addressed in the paper? At first skimming, it just says that a "sufficiently souped up laptop" could, in principle, compute the future of the universe (i.e. Laplace's daemon), but I haven't seen anything about the subsequent questions of time scales.

Computing the future is cool, but computing the past state is also really cool as it essentially allows time travel into (a copy of) the past.

The real universe might be different and far more complex than our simulated reality. Maybe a species that can freely move within 4 or 5 dimensions is simulating our 3D + uni directional time reality just like we „simulate“ reality with Sim City and Sims.

but then we don't have a universe simulating itself, but simulating a low-fi imitation

You're predicating on particles, heat death, etc as you understand it being applicable to any potential universe. Such rules are only known to apply in this universe.

A universe is simply a function, and a function can be called multiple times with the same/different arguments, and there can be different functions taking the same or different arguments.

The issue with that in terms of the simulation argument, is that the simulation argument doesn't require a complete simulation in either space or time.

It also doesn't require a super-universe with identical properties and constraints.

There's no guarantee their logic is the same as our logic. It needs to be able to simulate our logic, but that doesn't mean it's defined or bound by it.

Thanks for this great comment!

> He also uses Rice’s theorem (old) to show that there is no uniform measure over the set of "possible universes."

I assume a finite uniform measure? Presumably |set| is a uniform measure over the set of "possible universes".

Anyway if I understood that correctly, than this is not that surprising? There isn't a finite uniform measure over the real line. If you only consider the possible universes of two particles at any distance from eachother, this models the real line and therefore has no finite uniform measure.

Okay, here's the thing: this is creating revenue, this is fascinating literature for a huge class of armchair scientists that want to believe, want to play with these mental toys, and are willing to pay for the ability to fantasize with ideas they are incapable of developing on their own. This is ordinary capitalism, spinning revenues out of sellable stories.

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