It's difficult to be optimistic, even guardedly so, when the lights go out and we're left gropping around in the dark.

So the rules of the game have now changed. Our global financial system has become so complex and opaque that we've moved from a world of risk to a world of uncertainty. In a world of risk, we can judge dangers and opportunities by using the best evidence at hand to estimate the probability of a particular outcome. But in a world of uncertainty, we can't estimate probabilities, because we don't have any clear basis for making such a judgment. In fact, we might not even know what the possible outcomes are. Surprises keep coming out of the blue, because we're fundamentally ignorant of our own ignorance. We're surrounded by unknown unknowns.