Yesterday, I tried to define a complex adaptive system -- I said it was made of autonomous agents whose interactions produced emergent properties that couldn't be explained by looking at the agents individually.  The guy I was talking to was a string quartet player (a real one), and he said, "Like a string quartet!"  Exactly like a string quartet.

I'm attending a class put on by the New England Complex Systems Institute (NECSI) at MIT this week  Big title:  Complex Physical, Biological, and Social Systems.  The syllabus says it will be a "coherent program."  Here's hoping.