What is complexity theory? Let's let Wired explain:
There's something that will strike fear into the hearts of mathematicians and computer scientists everyhwere: non-linear emergent phenomena. Everybody knows that that is the last thing you want to be modelling.
Not a religiously inspired revision -- intelligent designers need not apply. Nobody suggests that genetic mutation and natural selection aren't responsible for the evolution of birds from reptiles or humans from tree-swingers.
But a growing number of scientists do say that neo-Darwinian evolution doesn't explain certain jumps in biological complexity: from single-celled to multicellular organisms, from single organisms to entire communities.
The jumps -- saltations, in complexity parlance -- appear to be non-linear emergent phenomena, the result of networked interactions that produce self-organization at ever higher levels. From this perspective, Darwinian evolution is a mechanism of a higher universal law, perhaps even a variant on the second law of thermodynamics.
Personal fears aside, this seems like a reasonable extension. It is important to find out how certain networked properties emerge, whether they be multi-cellular organisms, or human societies.
Now, some people, including me before I read this article, might think that classic evolution might be all we need to explain these jumps. Just because we haven't figured it out yet, doesn't necessarily mean that we need a new framework, right?
Maybe, but the second Wired article that caught my eye gives more evidence that our current view of evolution may limit our ability to explain certain phenomena.
When Guy Hoelzer runs computer simulations of organisms living in the modeling equivalent of a featureless plain, he sees them break into different species -- even though there's no reason for natural selection to take place.
That preliminary but tantalizing finding hints at some larger phenomenon driving the mechanisms of neo-Darwinian evolution. Hoelzer thinks the phenomenon is self-organization: combine energy with complex networked interaction and order will emerge.
As with all experiments based on simulation, you have to take this with a grain of salt, but it's certainly more fodder for complexity theory.One thing I don't quite agree with is that they try to relate it back to the second law of thermodynamics. ("The entropy of an isolated system not in equilibrium will tend to increase over time, approaching a maximum value at equilibrium.") That seems doubtful to me (speciation is entropy?) and also a bit premature. Save the unification with physics for when you've worked out the details of your theory.