Paradigm shifts tend to happen slowly, and then all at once. That's the lesson I've taken away from the recent market turmoil. The surprise is only that the upset didn't come sooner.

Pundits may have pegged the worst Dow drop of the year to fresh bond yield curve inversions in the United States (a historic predictor of downturns) but the underlying signs of sickness in the global economy have been with us for a long time. The question was when the markets were going to put aside the complacency bred by a decade of low interest rates and central bank money dumps, in the form of quantitative easing, and embrace this new reality.