What is "emergent"; what is "fundamental"?

marcus

Bee Hossenfelder had an interesting discussion of the term "emergent" back in mid 2008:
http://backreaction.blogspot.com/200...uctionism.html

There are apparently several ways the term is used in theoretical physics. Several different types of emergence.

Then this year she had a discussion of the different things "fundamental" can mean:
http://backreaction.blogspot.com/200...ndamental.html

Chronos

Here is a recent paper that makes a stab at defining causality.
Entropy for theories with indefinite causal structure
Sonia Markes, Lucien Hardy
http://arxiv.org/abs/0910.1323

Fra

One can also consider the case of emergent objectivity by evolution in the sense of "democracy of observers". This is close to how I like to think of it, and it's a emergence in the sense of each observer negotiating towards some kind of equlibrium with it's own environment that fits well with the evolving law perspective, where there is selection among the systems due to the collective opinon. An inertia is also present in which prevents arbitrary variation, because the environment gives stability that favours constrained variation only, arbitrary variation is strongly damped.

This is my preferred interpretation that is somewhat different that smolins specific CNS, but still I think in line with his overall spirit of evolving law and it is not necessarily inconsistent with it since there is I think a close analogy to black hole horizon and general observer horizons. Maybe the blackhole idea is more "concrete" than the general observer horizon thing which probably seems even more abstract.

Fundamental I personally think of as "irreducible information", and this is in my view observer dependent. What is irreducible to one observer, need not be to another observer. It's no inconsistency to me.

But then I'm free of even the slighest form of observer invariant realist ideals. Since realism in the classical sense can also be emergent in the democracy of observer sense.

/Fredrik