Rebuilding Quantum Theory From Simple Physical Principles • Hacker News Board

Re: Rebuilding Quantum Theory From Simple Physical Principles

#51

Post by gilbetron » Sat, Nov 25, 2017, 6:05 PM UTC

danbruc wrote: post #28

gilbetron wrote: post #23

Earlier quoted context omitted.

Why are you unable to distinguish it? It is not, a priori, impossible. It is entirely possible that there may be ways to determine if we are in a simulation, depending on how the simulation is done. No simulation is perfect, and it is theoretical feasible to find the imperfections.

To look for imperfections in a simulation requires knowing what the real thing actually looks like. If our universe is a simulation, where do you get the knowledge from what a real universe looks like?

As a very crude example, imagine if there were "invisible walls" in our universe like many video games have. Were we to bump into one, or somehow find it, we would then try to figure out a scientific explanation, but if we ended up with a bizarre, labyrinthine theory after trying our hardest, well just maybe we are in a simulation. You could then try to come up with how our simulation works, and then come up with tests to prove those theories.

Now, in the end, if we are in a simulation, that simulation (or one of its "parents") is reality, and so effectively we are all bound by the physics of the base reality, so one could argue that there is no harsh line between our simulations' physics and reality's physics, but that's another thread ;)

Re: Rebuilding Quantum Theory From Simple Physical Principles

#52

Post by QAPereo » Sun, Nov 26, 2017, 12:28 AM UTC

chr1 wrote: post #33

QAPereo wrote: post #8

Earlier quoted context omitted.

I have to disagree and I can not really understand what is so appealing about the simulation idea to many. You can’t see the appeal of an unfalsifiable conjecture that everything including us, is an intentional creation of some manner of vast and powerful intelligence? Aliens, Simulators, Bulk Beings, or you know... Gods. It’s just new window dressing on an ancient dream.

The question "whether we live in simulation" is indeed a new dressing. But the question "is simulation possible, and if yes what it can look like" is new, and can have useful answers.

But the question "is simulation possible, and if yes what it can look like" is new, and can have useful answers.

That is pretty interesting, but now how most people formulate the issue. After all, what we could simulate, or what could be simulated in a universe like ours, in principle is pretty interesting. The question of what another reality simulating us would be like isn't, because it could be absolutely anything at all. Questions without the hope of answers are, to me at least, not interesting.

Re: Rebuilding Quantum Theory From Simple Physical Principles

#53

Post by gilbetron » Sun, Nov 26, 2017, 12:58 AM UTC

danbruc wrote: post #36

chr1 wrote: post #30

Earlier quoted context omitted.

You can look for contradictions, inconsistencies or for macro scale phenomena not explainable by micro scale laws.

That doesn't work. The rules used by the simulator could just be the rules of the real universe, you can not tell the difference. Or to put in programming terms, you are given an object x to inspect, our universe, and you have to decide whether it is an instance of class RealUniverse or an instance of class SimulatedUniverse but you have no knowledge of what any of those classes looks or behaves like.

You seem to be arguing that it isn't always possible to detect you are in a simulation, whereas the rest of us are arguing that it could be possible in some simulations.

Re: Rebuilding Quantum Theory From Simple Physical Principles

#54

Post by jamesrcole » Wed, Nov 29, 2017, 1:45 AM UTC

gilbetron wrote: post #53

danbruc wrote: post #36

Earlier quoted context omitted.

That doesn't work. The rules used by the simulator could just be the rules of the real universe, you can not tell the difference. Or to put in programming terms, you are given an object x to inspect, our universe, and you have to decide whether it is an instance of class RealUniverse or an instance of class SimulatedUniverse but you have no knowledge of what any of those classes looks or behaves like.

You seem to be arguing that it isn't always possible to detect you are in a simulation, whereas the rest of us are arguing that it could be possible in some simulations.

I think they're arguing that whatever evidence you think you've found for it being a simulation could always just be how the universe is.

Re: Rebuilding Quantum Theory From Simple Physical Principles

#55

Post by chr1 » Sat, Dec 02, 2017, 6:09 PM UTC

wruza wrote: post #48

chr1 wrote: post #38

Earlier quoted context omitted.

> with analytically predefined series of events. This doesn't make universe less interesting or more predictable. Consider Mandelbrots set, it is fully analytically predefined, but only way to find it's details is to perform the whole calculation. Similarly the universe can be predefined, but the only way of finding its state after some amount of time can be performing a calculation fully equivalent to letting the un…

>amount of time can be performing a calculation fully equivalent to letting the universe to live for that time This one is very interesting since it brings back the question what time really is. Your point involves “metacircular” observer that can only work/simulate as fast as it can, but the definition of “fast” is external to it. Sure, if we simulate predefined-but-calc-required in our universe, then it will take t…

Say it is possible to calculate future of a sufficiently complex physical system like a person on a Turing machine by knowing the current state of the system.

Then, according to this idea, the calculation can not be simplified by using some kind of formula that predicts the final state, and one needs to fully compute all the intermediate states, which means your computation is fully equivalent to that person living for the time for which you want to calculate the final state.

So time here is the internal time for the system of your calculation, and not related to the time you take to calculate. This internal time is nothing more than a counter you use, and You can actually stop your calculation, change something in the initial state and calculate again.

I find this fascinating because it kind of explains the universe being predictable, and people having free will: everything is predefined, but only way to know what the choice of complex system will be is letting that system to make the choice!

If the view that consciousness can be explained without requiring quantum physics is correct, then this is true independently of specifics of simulated/real universe, and is just the way information/computation works.

But then maybe Penrose is right, and consciousness can't be calculated on a Turing machine, and we still have lots of interesting science to discover.

Re: Rebuilding Quantum Theory From Simple Physical Principles

#56

Post by chr1 » Sat, Dec 02, 2017, 6:20 PM UTC

QAPereo wrote: post #52

chr1 wrote: post #33

Earlier quoted context omitted.

The question "whether we live in simulation" is indeed a new dressing. But the question "is simulation possible, and if yes what it can look like" is new, and can have useful answers.

But the question "is simulation possible, and if yes what it can look like" is new, and can have useful answers. That is pretty interesting, but now how most people formulate the issue. After all, what we could simulate, or what could be simulated in a universe like ours, in principle is pretty interesting. The question of what another reality simulating us would be like isn't, because it could be absolutely anything…

True, if we go specifically searching for the answer to the second question, we may not find much interesting, but when we know more about the first question we can gain some insights about the second one.

So if by not interesting you mean `this door is closed now, revisit later` i completely agree with you!