A brief synopsis of the human condition...

It is important to appreciate that the financial system is complex, not merely complicated. A complicated system, such as a smartphone, has a fixed structure, so it behaves in ways that are predictable and controllable. A complex system has an evolving structure, so it can evolve in ways that no one anticipates. We will never have a proven understanding of what caused the financial crisis, just as we will never have a proven understanding of what caused the first World War.

-Arnold Kling, as culled from this ten year old essay