Comment by GistNoesis | Hacker News Reader

Comment by GistNoesis | Hacker News Reader

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Rules of the universe appear to us relatively simple. But the question of numerical stability is not solved specially for later times.

In physics it is natural to start from an initial state and integrate through time, starting from initial time and evolving by time-stepping.

Physics helps but this doesn't prevent the emergence of numerical instabilities like a big-computer being built.

So if you were running a universe simulation, when a life form start to emerge and starts building a big computer you can "erase" them from existence by approximating them away.

When your simulation starts crawling to an halt, you modify locally the current phases at the time of the modification so that the alien go extinct, and you propagate backwards in time towards the origin of the universe, to find the initial parameters of the simulation that when inputted make the alien never be a problem in the first place while not modifying too much the rest of the universe at current time.

From the perspective of a being inside the universe, the only thing we could observe by such a parameter search on the spaces of possible universe, are being amazed at how some constants of the universe seem to be fine-tuned.

And why exactly would someone go to all this trouble instead of just throttling that region of space? Surely you don't mean to say it would all run on a single chip?

And if this was a simulation there'd presumably be a purpose to it and once heavy computation emerges the entity running the sim would throw more resources at this interesting phenomenon, not try to get rid of it.

It'd be like "each time the neural net achieved AGI, the humans tore it down to refocus on the real goal, bombproof traffic sign recognition".

> It'd be like "each time the neural net achieved AGI, the humans tore it down to refocus on the real goal, bombproof traffic sign recognition".

Except that if the entity who's running the simulation is itself AGI, it really does not have interest in discovering yet another AGI in its own simulation.

It's not so easy to contain life. Potentially it can send information at light-speed and your whole universe become infested with a boring paper-clip AGI. Throttling will create problems at the boundaries for the conserved quantities, and for reproducibility.

But the mechanism I suggest, is a rather elegant (chaos resistant) way to allow to give control over a deterministic universe simulation without having to restart from the beginning, it is akin to re-rolling the dices if you don't like the result.

It is a somewhat natural way to search for the initial configuration of the universe. It present some nice properties. For example you can archive a whole universe by its seed. Which allows many more interesting search strategies. Like in chess you can create variations to guide the search towards region which are of interests for you.

I'd like to entertain the idea, that Bottled Universe Inc. , has to ship some Tera-Year old universes by Xmas. They have created plenty of variations in the universes and selected one just for you. You plug the seed, and you are guaranteed to see the emergence of beautiful universe when you run it inside your less powerful computer-brain.

> From the perspective of a being inside the universe, the only thing we could observe by such a parameter search on the spaces of possible universe, are being amazed at how some constants of the universe seem to be fine-tuned.

That's a good point, and I've also always wondered how fine-tuned those constants are. One problem though, is that changing the initial parameters would most likely have chaotic effects as the system (the whole universe) seems unstable and fragile. For example, it would be extremely difficult to fine-tune the parameters such that billions of years later at this moment, I don't write this comment.

One advantage of QM is that from outside the universe you still have some degrees of freedom : you can modify the phases without impacting the observable of the world.

You can make a pretty strong local change like flipping a coin, at any point in space-time without impacting the rest of the phases elsewhere too much, because the farther away in time and space from your modification, the more decoherent the phases would be and therefore their impact would be minimum.

And because the QM equations are time-reversible, you can propagate them backwards through time up to the origin of time. And you now have a new almost identical initial configuration, which when simulated forward will give rise to a universe that behave the same way until the time of the modification but then bifurcate.

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