While investor sentiment may be swayed by from time-to-time by fluctuations in emerging markets, the value of U.S. stocks depends on the successes or failures of American companies, Vanguard founder Jack Bogle told CNBC on Thursday.
"In the long-term … all value [is] created by corporations, which means, in an odd way, stocks are derivatives," Bogle said in a "Squawk Box" interview. "They're derivatives of the value created by our corporations."
He predicted that stock "valuations are high, but not extremely high," and earnings should "grow 4 percent or 5 percent per year."
But Bogle did question investors' reliance on earnings—saying it's deteriorated over the years. "Earnings don't mean what they used to mean. In particular, if you look back at last year's reported earnings after all the writeoffs, the P/E [price-to-earnings ratio] is about 20 times."
"If you look ahead, which is what Wall Street does, this year's operating earnings … without all those bad things in them, the P/E goes down to 15 [times]," he continued. "That's why I say the P/E is somewhat on the high side."
In a separate interview, Louis Navellier, chief investment officer of Navellier & Associates, said he's buying the recent decline in U.S. stocks on the back of the "best earnings in almost three years."
"One the catalysts of all these stock buybacks and better economic news is the weak dollar," he said.
The weaker dollar creates a windfall for Corporate America because "half the S&P sales are outside the United States," Navellier said. "So anytime the dollar gets weak it really helps large-cap multinationals."
As a champion for the individual investor, Bogle also stressed the importance of dividends, which he said are " fundamental to the investment equation."
"Ever since the 'great dividend disaster' of 2007 [to] 2009 when the financial stocks pretty much eliminated their dividends, we've had very good dividend increases year after year."
Right now, he estimated the average dividend yield at 2 percent.
—By CNBC's Matthew J. Belvedere. Follow him on Twitter @Matt_SquawkCNBC.
