

How chaos rules complex systems and our existence - niels
http://amix.dk/blog/viewEntry/19457

======
kirse
_Today we try hard to find a theory of everything in physics, something that
fully explains and links together all known physical phenomena. But I believe
that this isn't possible._

This really touches on the philosophy of science, and I don't think this will
ever be possible inside the "box of spacetime" that we exist in.

I would love to see a complete explanation that explains Bell's Theorem in
alignment with the phenomenon of quantum entanglement before I die, but I'm
pretty convinced that we have reached the ultimate limitations of how far we
can zoom into the wall on our own little "box" that we live in.

~~~
jerf
We can not, from within the system, conclusively _prove_ that we have found
the correct laws. For all we know, in a thousand years, the laws of physics
will completely change, with absolutely no clue given in advance. And I don't
mean different vacuum states or anything like that, I mean, _completely_
different physics. We can't prove it won't happen, only be Bayesian-very-sure
it won't, which isn't the same.

However, nothing _necessarily_ stops us from determining the laws of physics
all the way to the bottom. There's no contradiction there, only a question of
whether they are "too far" away for us to see them or we are unable to gather
enough information, not because it is fundamentally impossible to figure out
the substrate you are running on but simply because the substrate itself
happens to be too fuzzy to tell. Already, we're to the point where if you
built a universe off of the standard model and added some hacks to cover the
cases where we know it doesn't work, you could probably build a correct-enough
simulation to support life.

(Also, rather than posting again: I strongly disagree with the author's claim
that the real world is more complex than math. Math is _radically_ ,
infinitely more complex. The real world is a vanishing subset of possible
mathematical structures, regardless of what shape it takes.)

~~~
kirse
_Already, we're to the point where if you built a universe off of the standard
model and added some hacks to cover the cases where we know it doesn't work,
you could probably build a correct-enough simulation to support life._

You really think we even understand .1% of all there is to know about this
universe?

~~~
jerf
There's a meme where it is chic to claim ignorance about even things that we
know. Yes, the truth is that we do in fact know a lot about particle physics
now. The problem with knowing things about the universe doesn't lie at that
level. The problem is knowing what 10^40 particles are up to at any given
point in time.

You are conflating understanding the laws with understanding all implications
of the laws.

------
spot
Interesting post, but I don't agree with its conclusion. The "Theory of
Everything" in Physics is equivalent to finding the axioms of Mathematics. It
does not give us a way to determine the truth of any physical law (say about
climatology, just like knowing the rules of Conway's Life doesn't allow you to
determine the status of any theorem about it) and so it does not cross the
halting problem. The relative "complexity" of math vs physics is not relevant
and anyway, until we have a TOE we don't know its complexity.

