Updates with market close. Updates chart. Adds quotes from other analysts.

The plunge in global stock markets took the Standard & Poor’s 500 Index down to 1,862 today and has set off a shouting match between bulls, who expect a quick recovery, and bears, who think stocks have farther to fall. Trillions of dollars are riding on who’s right. We talked to top market analysts on both sides of the debate to get a deeper understanding of their arguments. Here’s what they said.

First, the bears.

Lindsey Piegza, chief economist of Sterne Agee in Chicago, argues that the gains in the stock market got way ahead of progress in the real economy. “Either the economy has to pick up enough momentum to justify where the stock market has been or we’ll see a sizable correction to the stock market.”

What’s happening now, she says, is that “the stock market is reacting to the more lackluster reality that the [Federal Reserve] has been pointing to for months.” She adds: “A lot of that growth has been driven by M&A [mergers and acquisitions], debt financing, and unlimited Fed-printed dollars. Which is coming to an end in October.” (The Federal Open Market Committee has said it probably will end its purchases of bonds at the end of this month.)

Today’s economic news was especially grim, Piegza says. A report on retail sales showed that “consumers are losing momentum despite lower gas prices, which are only a temporary support.” A report that wholesale prices fell slightly in September “will exacerbate disinflationary fears.” And the Empire Manufacturing Survey index dropped sharply, which Piegza says shows that “consumers can’t absorb the elevated level of production.”

Piegza says some people have trouble facing up to reality. “A lot of economists, just like the Fed … see what we want to see, what we hope to see. We’re hoping that GDP improves; this invisible hand is just going to pick up the economy.” She worries about uncertainty introduced by regulation and “onerous” costs of health care. “I’m struggling to see what can propel the U.S. economy beyond this 2 percent GDP range.”

Piegza’s colleague Carter Worth, Sterne Agee’s chief market technician, wrote in a piece published on Monday that “the odds are zero” that the stock market correction is over. So far he’s been right in spades. Worth uses chart analysis to predict where the market is headed, and by his readings, the S&P 500 index is likely to revisit its April low of 1,815, and a level of 1,765 is “certainly possible.” For the record, 1,815 would be about 10 percent off the index’s September high, and 1,765 would be about 12 percent below it.

For Doug Ramsey, chief investment officer of Leuthold Group in Minneapolis, alarms started going off this past spring when Leuthold’s measure of investor optimism hit an all-time high. As a contrarian, Ramsey took that as a sign that everyone who might buy stocks was already in the market, so the only way to go was down. “I tend to think that we’ll go a little deeper, maybe considerably deeper, than a 10 percent correction,” Ramsey says.

Douglas Noland is even more down on the market. Noland is senior portfolio manager of Federated Investors’ Prudent Bear Fund, which means he’s all bear, all the time. Noland refuses to give a price target for the S&P 500. “We’re in the midst of the biggest bubble in history, and now there are cracks. This unwind, once it starts, who knows how much lower it could go, but a lot lower,” Noland says. “The probabilities for a financial accident are very high now. I hesitate to use the word ‘crash,’ but a market dislocation, a liquidity event.”

“We’re in a global, government-financed bubble, the granddaddy of all bubbles,” Nolan argues. “I’m more worried now than I was in ’07-’08, for what it’s worth,” he says. Back then, central banks stepped in to lend money when private players were pulling back. This time, he says, central banks may not be able to play that role.

“You’re seeing important changes in views. Globally now, with the collapse in commodity prices. Venezuela is not fine” because it needs expensive oil to pay its bills. “Greece a month ago looked fine” because investors were happy to lend to it at low interest rates. “Today they’re not fine.”

“Today’s a panic,” Noland concludes. “It’s just messy.”

Now, the bulls.

The bullish case is a lot less exciting. It views the current turmoil as a blip and a buying opportunity. In late September, Julian Emanuel was regarded as a bear because his forecast for the S&P 500 for the end of this year—1,950—was the lowest among those strategists surveyed by Bloomberg. Now “we look like we’re raging bulls” simply by keeping that forecast, says Emanuel, who is executive director for U.S. equity and derivatives at UBS (UBS ) in New York. “It’s our story, and we’re sticking to it.”

Philip Orlando, chief equity market strategist for Federated Investors, expects the S&P 500 to climb to 2,100 by the end of this year and to 2,350 by the end of 2015. He points to the enormous rally in the Treasury bond market as a potential positive for the stock market. Investors have a choice between stocks, which produce earnings that can be turned into dividends and capital gains, or bonds, which produce interest payments. Soaring bond prices could cause investors to switch over to stocks, says Orlando. Share prices would have to triple for stocks to be as expensive in relation to their current earnings as 10-year Treasury bonds are in relation to their interest payments, Orlando calculates. ”Stocks are out of whack. Bonds are out of whack. Over the next 15 months that gap will start to close.”

OK, but couldn’t it close by bond prices falling, rather than by stock prices rising? Not likely, Orlando says, because of his “optimistic view of corporate earnings and the economy.” Companies have begun reporting their profits for the July-September quarter, and in the early going revenues are up 6 percent and earnings up 13 percent from a year earlier, Orlando says. Half the reporting companies have reported higher revenue than expected, and two-thirds have reported higher earnings than expected, he says.

Orlando notes that his firm predicted the stock market rally in 2009, when things looked dark, and has stayed more optimistic than most ever since. “We’ve been lunatics the entire cycle, and let the record reflect that, at least up to this point, we’ve been right.”

Orlando even manages to find a silver lining around the clouds of “dismal” Europe and Japan. “They’re so bad that in our view, we feel that it absolutely demands a policy response. Those economies cannot continue business as usual.” As for today’s negative economic reports—noise. “The fact that we got one bad data point doesn’t mean the cycle is over.”

Barry Bannister is a bull, too, although he’s not feeling too good about his call right now. Bannister, the top equity strategist at Stifel Nicolaus, was a long-time bear but abruptly turned bullish in August and set a year-end target of 2,300 for the S&P 500. That put him higher than any of the other 19 strategists tracked by Bloomberg. Bannister says earnings “look like they’ll be pretty good” and says that while global economic indicators have dipped, “they’re nowhere near where we were in past major economic downturns.” So he’s standing by his bullish call. But he told Bloomberg News, “We definitely pulled the trigger too early and it looks like it’s catching up to us.” He adds, “There is a real issue of global deflationary pressures, and the hysteria around Ebola and the Middle East isn’t helping.”