Doomsdayers have many ideas about when and how the world will end.

Most people go through their daily lives assuming that tomorrow will be a lot like today. No pits of fire will open up, society won't collapse, and the world, most likely, won't end.

But for others, doom has a certain appeal.

The most famous example these days is Harold Camping, a California-based Christian radio broadcaster who believes that May 21, 2011, will mark Judgment Day, ushering in five months of torment for the unsaved until the universe finally ends on Oct. 21. Camping has bought billboards and dispatched caravans of believers around the country, warning the world of its fate. [Infographic: A Brief History of Doomsday]

"It's going to be a wonderful, wonderful day," Camping told a San Francisco Chronicle reporter last June.

Camping has made this prediction before, in 1994 — it didn't pan out — but the thousands of failed doomsday predictions throughout history are no match for what Lorenzo DiTommaso, a professor of religion at Concordia University in Montreal, calls the "apocalyptic worldview."

"It's a very persistent and potent way of understanding the world," DiTommaso told LiveScience.

Problem-solving through doomsday

According to DiTommaso, the apocalyptic worldview isn't uncommon. At the extreme end are people like Camping or Aum Shinrikyo, a Japanese doomsday cult that carried out sarin gas attacks on the Tokyo subway in 1995. But doomsday appeals to the secular and well-adjusted as well, through books such as Cormac McCarthy's "The Road" (Knopf, 2006) and movies like "The Terminator" (1984). Meanwhile, economic hard times and crises like Japan's earthquake and tsunami have spiked interested in survivalism and "prepping," or stashing food and supplies in preparation for a coming collapse.

Apocalpytic beliefs have been on rise for the past 40 to 50 years, said DiTommaso, who has been researching doomsday believers for an upcoming book, "The Architecture of Apocalypticism." What ties these disparate groups together is a sense that the world's problems are too big to solve, DiTommaso said.

"Problems have become so big, with no solutions in sight, that we no longer see ourselves able as human beings to solve these problems," DiTommaso said. "From a biblical point of view, God is going to solve them. From other points of view, there has to be some sort of catastrophe."

The apocalyptic worldview springs from a desire to reconcile two conflicting beliefs.

"The first is that there is something dreadfully wrong with the world of human existence today," he said. "On the other hand, there is a sense that there is a higher good or some purpose for existence, a hope for a better future."

Viewing the world as a flawed place headed toward some sort of cosmic correction reconciles these two beliefs, DiTommaso said.

And because believers are certain that their sacred text can never be wrong, failed doomsday predictions only convince them that their own interpretations were flawed, opening the door to new predictions. Historically, those who have predicted doomsday, including the early Christians, have been persecuted and oppressed, so the prospect of a final judgment is comforting, DiTomasso said.

"Despite fire, death and destruction, the god of apocalypticism is a god of order, not chaos," DiTomasso said. "That's the reassurance."

TEOTWAWKI, and they feel fine

To be reassured, however, an end-of-world Jane has to expect doomsday to come soon — and has to expect to survive. Religious believers usually expect that they'll be among those saved from the torments of an ending world. Secular doomsday-fearers, on the other hand, expect to fight for their survival.

"We stress being prepared," said Jim Rawles, the proprietor of SurvivalBlog.com, an online clearinghouse of advice on survivalism and preparation. Rawles, who gives his location only as "west of the Rockies," has been involved in disaster preparedness since he was a teenager. In the 1960s, with nuclear attack fears running high, Rawles and his friends talked about preparedness a lot, he told LiveScience.

Rawles started SurvivalBlog in 2006. Since then, he said, his readership has shifted from mostly conservative Christians and Orthodox Jews to "Birkenstock-wearing, liberal greenie-types." The Japanese earthquake and nuclear meltdown brought him more readers across the political spectrum, he said, and he now gets more than 260,000 unique visitors to his site each week.

Unlike Camping, Rawles and his readers aren't preparing for the end of the world; they're preparing for TEOTWAWKI, survivalist shorthand for "the end of the world as we know it." The end might come in the form of an economic collapse, a giant solar flare, a nuclear attack or climate change, but the end goal is the same: to be ready for anything. [End of the World? Top Doomsday Fears]

"There's a great deal of satisfaction in saying, 'Oh boy, I'm ready when the bombs go off/the environment collapses/the Arabs invade/the magnetic poles reverse,'" said Richard Mitchell, an Oregon State University sociologist who spent years getting to know survivalists for his book "Dancing at Armageddon: Survivalism and Chaos in Modern Times" (University of Chicago Press, 2002).

Paranoid or prepared?

Survivalists have gotten a reputation as fringe-dwellers, Mitchell said, but viewing them as crazy is "totally incorrect." For one thing, they're everywhere: Mitchell described one man, a suburban engineer whose garage was filled floor-to-ceiling with detergents and hand wipes and toilet tissue. The man's job specialty, Mitchell said, was water systems engineering, and his concern was a loss of sanitation after a disaster.

"He's not some redneck, and he's not violent," Mitchell told LiveScience. "He wants to help keep everybody clean."

People who are into survivalism and prepping enjoy telling stories about the world turning upside-down, Mitchell said. Society's collapse is a challenge, and the reward is coming up with scenarios in which you survive.

"People will tell you five or six stories, totally different apocalyptic tales, and everybody will nod their head and say, 'Yeah, that sounds right,'" Mitchell said. "Who cares? It's the storytelling that matters."

As do the life skills. To Rawles, prepping is a way of reaching back to his family's pioneer roots, when gardening, canning and putting up food were standard procedures.

"Preparedness can in some ways be a lot of fun, because you're learning some really interesting skills," Rawles said. "And the sense of accomplishment where you can walk down to your basement and look at your pantry shelves and say, 'Yep, I did that,' you can feel good about that."

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