If you are going to write a blog about complexity science sooner or later you have to define, or at least describe, what you mean by that. And, I'm afraid, my time is now. My reticence is due to the many who have tried and, basically, failed to write a useful definition. Saying that complexity science is the study of complex systems isn't any help -- what's a complex system? Wikipedia's discussion of complex systems is interesting but declines to offer a definition.
So I was excited to see this article in the Harvard Business Review. The authors
". . believe the time has come to broaden the traditional approach to leadership and decision making and form a new perspective based on complexity science."
I love that! However, while their description of complexity science has some things to like, it reads like a laundry list of buzz words. And then there is this assertion:
". . .in a complex system the agents and the system constrain one another, especially over time. This means that we cannot forecast or predict what will happen."
Seems to suggest that we should give up all hope! If you've read my post on Strategic Planning then you know that I believe that we can take effective management action in complex systems and create a surprising level of predictability.
From my perspective the defining characteristic of a "complex system" is that it produces complex dynamic behaviors from the interaction of its parts.