by Jim Rickards, Daily Reckoning:

At some point, systems flip from being complicated, which is a challenge to manage, to being complex. Complexity is more than a challenge because it opens the door to all kinds of unexpected crashes and events.

Their behavior cannot be reduced to their component parts. It’s as if they take on a life of their own.

Complexity theory has four main pillars. The first is the diversity of actors. You’ve got to account for all of the actors in the marketplace. When you consider the size of global markets, that number is obviously vast.