The actual debate is no joke: Whether the developed world is in a new era of of "secular stagnation," or permanently slower growth not tied to a regular economic cycle. Summers is a proponent of the theory, while Bernanke has argued against.
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Dalio believes tepid expansion is here to stay. "We (the United States, Europe and Japan) are in a period of secular stagnation," he wrote in the April 7 note obtained by CNBC.com.
Echoing a point he has made in previous public remarks, Dalio wrote that the Fed and other central banks have limited policy tools given already near-zero interest rates. That means less lending, and therefore less investment and lower economic growth. If interest rates stay the same, Dalio added, the economic boost from them will also taper off.
"Interest rate declines and debts increasing faster than incomes to pull demand and economic activity higher are largely a thing of the past," Dalio wrote.
Dalio's stagnation view is somewhat at odds with Bernanke.
"Does the U.S. economy face secular stagnation? I am skeptical, and the sources of my skepticism go beyond the fact that the U.S. economy looks to be well on the way to full employment today," Bernanke wrote in a recent Brookings blog post.
Bernanke has argued that there will always be profitable investments to make with very low interest rates, and that recent low growth levels were more from temporary pressures of the post-financial crisis economic cycle.
Former White House economist Summers is more in Dalio's camp on stagnation.
In a recent blog post responding to Bernanke, Summers said the "essence" of secular stagnation is "a chronic excess of saving over investment."
"If this is the case," Summers said, "monetary policy will not be able to normalize, there will be a continuing need for expanded public and private investment, and there will be a need for global coordination to assure an adequate level of demand and its appropriate distribution."
Summers believes government spending on infrastructure is a potential solution, one that Dalio wrote he supports in principal (Bernanke does, too, although he said recently it may not be satisfactory.)