Bitcoin is a hot topic, and for good reason: The digital currency, whose value has been on a roller coaster ride this year, crossed the threshold of $10,000 a coin for the first time and then kept going. Some predict it could "easily" reach $40,000 by the end of 2018.
"Avoid bitcoin like the plague. Did I make myself clear?" said the Vanguard founder in response to an audience question.
"Bitcoin has no underlying rate of return," Bogle continued. "You know bonds have an interest coupon, stocks have earnings and dividends, gold has nothing. There is nothing to support bitcoin except the hope that you will sell it to someone for more than you paid for it."
He's not the only skeptic. JPMorgan Chase CEO Jamie Dimon called bitcoin a "fraud," adding "it's worse than tulip bulbs. It won't end well." And billionaire investor Howard Marks called it a "pyramid scheme."
On the flip side, some of the biggest names on Wall Street are embracing the digital currency, including Fundstrat's Tom Lee and value investor Bill Miller, who is running a fund with nearly a third of its assets in bitcoin.
Then there's the camp occupying the middle ground, those who don't say it's the best investment but also don't say it's the worst.
Billionaire Mark Cuban seems to be among that group. As he told Vanity Fair, it's OK to invest up to 10 percent of your savings in high risk investments, including bitcoin. You've just "got to pretend you've already lost your money," he said, adding that it's like throwing "the Hail Mary."
But Bogle would advise steering clear of the speculative asset completely: "Bitcoin may well go to $20,000 but that won't prove I'm wrong. When it gets back to $100, we'll talk."
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