With the S&P 500 index having tripled since March 2009 and having escaped a 10 percent correction since October 2011, some experts expect sub-par market returns for years to come.

But not D. David Jilek, chief investment strategist for Gateway Investment Advisers. "History suggests an annualized return in the mid-teens over the next 10 years may be possible," he writes on MarketWatch.

Looking at the S&P 500 going back to 1928, 20-year annualized returns average 11.22 percent and 30-year returns average 11.24 percent, Jilek says. For the market to meet those averages for the periods ending in 2025, stocks would have to return an annualized 14.67 percent over the next 10 years to hit the 20-year average and 16.09 percent to meet the 30-year average.

To be sure, if the bull market lasts another 10 years, that would set a record by almost four years, Jilek notes.

So over the next 10 years, the current bull market may end, a bear market--defined as a 20 percent loss--may ensue, and stocks may still return an annualized 14.67 percent during the period, he says.

Elsewhere on the investment front, some analysts say that we're moving to the point where computer algorithms will perfectly determine financial asset prices.

It has even been suggested that a computer could match Warren Buffett's investing genius. Not quite, counters Nobel laureate economist Robert Shiller of Yale University.

"This imagined state of affairs might be called the financial singularity," he writes on Project Syndicate.

"Financial singularity implies that all investment decisions would be better left to a computer program, because the experts with their algorithms have figured out what drives market outcomes and reduced it to a seamless system."

But that doesn't jibe with reality, Shiller says. "Markets seem to be driven by stories. There are stories of great new eras and of looming depressions. There are fundamental stories about technology and declining resources."

Stories about Greece and China hurt U.S. stocks two weeks ago.

The stories may not always be true, but they affect the market anyway, Shiller notes. "The idea of financial singularity may seem inspiring, but it is no less illusory than the rational utopia that inspired generations of central planners," he maintains.

"Human judgment, good and bad, will drive investment decisions and financial-market outcomes for the rest of our lives and beyond."

As for Buffett, perhaps a computer program can match his past investing style. "But that does not necessarily detract from his genius," Shiller says. "Indeed, the true source of his success may consist in his understanding of when to abandon one method and devise another."

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