Greenspan claims the Federal Reserve can't prevent bubbles, that these excesses of ebullience are part of the natural order of a free economy.

FORBES: Fact and Comment

We have a foundation economically upon which to build in the 21st century that doesn't rely on financial bubbles or housing bubbles or .com bubbles, but relies on strength in our manufacturing sector, strength in education, strength in innovation and strength throughout the country economically.

WHITEHOUSE: Press Briefing

Greenspan and Bernanke cutting rates to zero, twice, didn't create any debt levered priced bubbles.

FORBES: Intelligent Investing Briefing Book

Back in the real world, since all trades balance, bubbles quite simply don't exist.

FORBES: Political Economy

Too much oxygen and the toxic ammonia in waste won't convert to nitrogen gas, which bubbles out.

FORBES: Muckraker

If you don't have one, just make sure the bubbles burst at a steady, controlled pace.

WSJ: Martin Picard's Fried Pancakes With Warm Maple Cream Syrup | Slow Food Fast

Gold may be a good hedge in times of uncertainty, but its rapid rise--and the talk about how it's a can't-lose investment--shows a striking similarity to the pattern of previous bubbles, like that in housing a mere three years ago.

FORBES

The European Central Bank and the Czech National Bank have what Poland refers to as ultralow rates, near zero, which aren't appropriate for the Polish economy because they would create boom-and-bust cycles and investment bubbles, Mr. Belka said earlier.

WSJ: Poland Hints at End to Rate Cuts