It’s been a hot day even for Las Vegas, and outside the South Point Hotel and Casino the morning traffic crawls in sluggish resignation. Few people linger in the gathering heat, preferring the shade of covered walkways to the merciless sun.

Inside the casino, however, is a different scene. A convention is filing out, and the crowd moves with quick, eager strides. Most are young—in the twenty-to-forty range. A stroll through the lobby reveals a mix of race, gender, and accents. This is a crowd that has assembled itself from across the world, and while faces are friendly and conversations playful, there is a steely sense of unity. Of purpose.

Of confrontation.

The Las Vegas convention is the latest installment of The Amaz!ng Meeting. First held in 2003 and colloquially referred to as TAM, it’s the annual mecca for skeptics around the world. In a culture-at-large that reveres faith above facts, skeptics are the vanguard of rationalism. Think James “the Amazing” Randi exposing psychics as charlatans. Think Mythbusters hosts Adam Savage and Jamie Hyneman using the scientific method with explosive aplomb. Think merry pranksters Penn & Teller debunking all manner of pseudoscience or conspiracy theory on their former show, Bullshit! These are the people who dare to demand evidence of those making extraordinary claims.They are people who make believers uncomfortable and often make enemies because of it.

In an earlier age, skepticism was not so much a movement as a pastime for older, male, upper-crust academics. It was spirited discussion over cigars and brandy. Today, the new skepticism is a grassroots revolution. Its adherents are media-savvy, and they use memes, humor, Photoshop, YouTube, and social networking to wage a bold offensive against the prevailing belief culture. They are ardently pro-science, descending like a phalanx of logic on creationists, homeopathic practitioners, faith healers, psychics, truthers, birthers, anti-vaccination crowds, and generally anyone else whose position isn’t supported by logic. Skeptics champion reasoned methodology, not blind belief. They respect critical thinking, not emotional reactionism. They are factual heavyweights, and now, after decades of polite disagreements with true believers, young skeptics are ready to take off the gloves.

Skeptical groups operate around the world and across the Internet via popular blogs, podcasts, rallies, meetings, and forums. Skeptical bestsellers flood the marketplace by luminaries like Richard Dawkins, the late Christopher Hitchens, Michael Shermer, and Sam Harris. Skeptics count celebrities like comedians Tim Minchin and Eddie Izzard among their ranks. They petition the United Nations to end real witch-hunts in third-world countries. They coordinate, collaborate, and rally their growing numbers.

Beyond TAM, the dedicated skeptic can make pilgrimages to myriad events like the Northeast Conference on Science and Skepticism, QED (“Question. Explore. Discover.”), Skepticon, Skepticamp, and regional pow-wows sponsored by groups like the Center for Inquiry or the New England Skeptical Society. The website Skepchick.org focuses on critical thought with a feminist bent. The Skeptic’s Guide to the Universe brings rational examination of the news in the form of a weekly, down-to-earth podcast. And Drinking Skeptically organizes gatherings for likeminded critical thinkers accompanied by some social drinking, and even offers a video chat version.

The James Randi Educational Foundation (JREF) is the veritable base camp for skeptical legions. Founded in 1996, the JREF’s mission is “to promote critical thinking by reaching out to the public and media with reliable information about paranormal and supernatural ideas so widespread in our society today.”

And to that end, the JREF is remarkably energized. They offer grants and scholarships, they publish works on critical inquiry across all media, they host TAM every year, and they provide a support structure for other skeptical groups. Most popularly, the JREF taunts true believers with the One Million Dollar Paranormal Challenge, promising to award the purse to anyone who can demonstrate, under controlled laboratory settings, evidence of the paranormal. First established in 1996, the challenge is open to all. No one has ever collected the prize money, and numerous “celebrity psychics” have kept their distance.

Randi himself, now eighty-three, continues to make the rounds of the lecture circuit. He’s the field’s leading rock star, speaking to crowds of likeminded rationalists on everything from spoon-bending to UFOs to bleeding statues to religion.

Starting out as a professional magician in 1946, Randi had switched hats by 1972 and has since aggressively “outed” psychics like Uri Geller and John Edwards, demonstrating how mentalist skills—sleight-of-hand and cold reading techniques—can be passed off as magical abilities. He holds particular disdain for so-called faith healers, who charge sick patients thousands of dollars to be “cured.” The patients leave, with lighter wallets and untreated diseases.

Unsurprisingly, skeptics take issue with the opinion that belief doesn’t hurt anybody. Even leaving out religiously motivated murder like the attacks on 9/11, skeptics have plenty of ire on this front. Take, for instance, the anti-vaccine movement, driven largely by the fraudulent claims of British doctor Andrew Wakefield that the MMR vaccine is linked to autism. As a result, vaccine rates saw a decline in the late 1990s and throughout the following decade, and they continue to stay below optimal levels; according to a 2011 study, one in ten parents in the United States are no longer following the recommended schedule of vaccinations. What’s troubling to skeptics is the reason: 81 percent of parents who skipped or delayed vaccines “disagreed” that unvaccinated children are at risk for epidemics. Subsequently, new outbreaks of diseases like measles are on the rise throughout the United States.

In light of such disturbing trends, skeptics see themselves as warriors in a noble tradition, casting off medievalism and marching towards a second Enlightenment. Indeed, they view history as a struggle between superstition and science; after all, it was Carl Sagan, perhaps the most idolized luminary in the cause, who called science “a candle in the dark.” Since Sagan’s death, it is skeptics who have taken that candle, and lit an army of torches to light the way into the future.

The Skeptics Speak

While skepticism has roots in ancient Greece, the modern movement is only about forty years old. It arose from a new pro-science mentality that was promoted, independently, through the writings of James Randi, Carl Sagan, Martin Gardner, and even Isaac Asimov. However, it was humanist and philosopher Paul Kurtz who got things organized.

Kurtz began publishing against pseudoscience in the 1950s, and has since authored several hundred articles promoting the skeptical viewpoint. He is the founder of the Committee for Skeptical Inquiry (CSI, formerly the Committee for the Scientific Investigation of Claims of the Paranormal), the Council for Secular Humanism, and the Center for Inquiry. He was also editor of the Humanist from 1967-1978. Arguing from a rationalist angle, Kurtz tackled everything from religion to psychics to exorcisms. The organizations he founded quickly filled with like-minded thinkers.

And just who are these like-minded thinkers?

Being so ardently pro-science, many skeptics naturally align with the political left. (A social conservative promoting creationism is in for a fight if a skeptic happens to be nearby.) Yet the movement is hardly the political arm of any one party. Young skeptics do tend to be highly educated, liberal, and agnostic or atheist, but skepticism is also rife with political libertarians, nonpartisans, and Goldwater conservatives. In fact, when their acumen takes aim at politics, a common sentiment among skeptics is that America’s two-party system is little more than theater for the masses.

One thing is common to skeptics everywhere: facts matter. The scientific method and critical inquiry trump blind faith and mindless rabble.

If the CSI crowd brought the modern skeptic movement to the plate, social media is now hitting the ball out of the park. In the last ten years, skeptical ranks have swelled, groups have multiplied, and a sense of global identity is bringing it all together.

“The movement has really grown in these last few years,” says skeptic Karen Stollznow. “It’s not just a bunch of older gentlemen who like to pontificate. It’s real grassroots activism.”

Stollznow exemplifies the new skepticism. An expat from Australia with a PhD in linguistics, she came to the United States in 2004 to do research at UC Berkeley. Now Stollznow writes columns for both Skeptic and Skeptical Inquirer magazines, hosts two podcasts (Monster Talk and Point of Inquiry) and is a research fellow with the JREF and CSI. In late 2011 she was a guest on CNN’s Anderson Cooper 360°, providing the skeptical viewpoint on people who charge thousands of dollars to remove “curses” from the gullible.

“I don’t really consider it skepticism,” she says. “It’s just the new common sense. Our movement and our way of thinking is growing tremendously. Belief in witchcraft and the supernatural is steadily dying out, and we have something to do with that.”

Ironically, Stollznow’s path to skepticism began with a personal interest in the paranormal. As a child, she was interested in tales of ghosts and ESP, but the deeper she read about them, the more she began to realize that evidence was lacking.

Intrigued, she contacted Australian Skeptics and began to work with them. She went undercover to psychic parlors, where she would receive “wild diagnoses” about her health that follow-ups with a medical doctor dismissed. She was taught to recognize the tricks and trades of psychics, and she realized that opposing them was a cause she wanted to embrace. “Belief isn’t harmless,” she says.

Dr. Steven Novella, director of General Neurology at Yale University School of Medicine, is another prominent voice in the skeptical community. In 1996 he was one of the founders of the New England Skeptical Society, and in 2005 he joined the burgeoning podcast world in launching the Skeptic’s Guide to the Universe (SGU).

“Systematic doubt and critical thinking are essential to any free society,” says Novella. “Especially in a democracy, where citizens make decisions about their civilization, the ability to think critically—and to question information—is absolutely crucial.”

SGU takes a casual, informal, and accessible approach to its subjects. Comprised of a team of so-called rogues, including Skepchick’s Rebecca Watson, the podcast is one of the finest examples of polished skeptical activism. Its panelists cover news items of scientific interest, feature famous guest interviews, and conduct regular segments like “Science Fact or Fiction” and “Name That Logical Fallacy.” They’ve even started making short films, and in 2011 hosted a special twenty-four-hour talkathon with special guests like Adam Savage.

“If the philosophy of science didn’t work, it would not have borne all the fruits it has,” says Novella. “We build a hunk of metal, send it across the solar system, and are rewarded with pictures of the outer planets—if science didn’t work, that wouldn’t happen. If science didn’t work, it would be just another belief system.”

Novella holds special ire for the alternative medicine and homeopathic industries. “They’re fundamentally anti-science and irrational. You know, it’s really easy to spread fear, and a lot harder to correct misinformation. Social media has been so successful for us, but a lot of our foes are well funded and have PR machines. Social media has leveled the field.”

Novella points to the believer enclaves that carve themselves out online, where “it’s possible to create a very insular community,” and anyone who doesn’t toe the party line is banned.

The skeptical message is often viewed as an open assault on a host of such “believer” camps: creationists, gay conversion therapists, psychics, the aforementioned anti-vaccine advocates, 9/11 truthers, Obama birthers, moon-landing deniers, Holocaust deniers, astrologers, Feng Shui practitioners, and other purveyors of mysticism and conspiracy theory of nearly every stripe and flavor.

“Ultimately skepticism is a tool, not a belief,” says George Hrab, a professional drummer and guitarist who explores skeptical and scientific themes in music. “It’s just the way you approach data.” Hrab’s involvement in skepticism began in the seventh grade, when he read Inherit the Wind, the play based on the infamous Scopes Monkey Trial of 1925. Not long after that he read Michael Shermer’s book, Why People Believe Weird Things, where he first encountered the word “skeptic.”

Since then Hrab has become an energetic voice in the movement, speaking at skeptic events and hosting The Geologic Podcast, a weekly program of comedy sketches, news commentary, music, interviews, and personal stories.

“There’s this idea that one of the best things you can have is faith, whether it’s in God or in government,” Hrab notes. “The truth is that it’s one of the worst things you can have. If you can believe in things without evidence, it leads to bad decisions. It affects the social construct.”

Says James Randi, “So long as our species continues to believe in magic, miracles, and supernatural powers and abilities, we will be held back from the intellectual progress that we should be enjoying. That’s why it’s so important for skeptics and our organizations to be active at every level, to take on nonsense in the media and give people the tools of critical thinking so they can protect themselves from these harmful distractions.”

Indeed, a great many participants in the new skepticism enjoy challenging religious proclamations with snappy, ironic, and witty responses. Consider the event known as Boobquake.

In April of 2010 Iranian Ayatollah Kazem Seddiqi proclaimed that earthquakes could be explained not by plate tectonics, but by God’s anger at women. “Calamities are the result of people’s deeds,” Seddiqi insisted. “Many women who dress inappropriately … cause youths to go astray, taint their chastity, and incite extramarital sex in society, which increases earthquakes.”

This astounding conclusion was immediately challenged by Purdue science student Jennifer McCreight, a feminist, skeptic, and author of the blog, “Blag Hag.” McCreight decided to use her breasts for science, declaring to her Facebook friends that on April 26 she would wear her most revealing shirt and challenge God to show his displeasure by creating an earthquake of Koranic proportions.

What followed was a media frenzy as more than 200,000 women signed up for the “event” and websites began discussing breasts, religion, and science. Not since Republicans decried Janet Jackson’s nipple as a threat to civilization had mammaries been such a culture war rallying point.

Another example of the new skepticism’s taste for the confrontational occurred back in March of 2008, when the producers of the pro-intelligent design documentary Expelled held a closed conference call to promote their film. Famously short-tempered evolutionary biologist (and 2009 Humanist of the Year) PZ Myers had other ideas; he managed to dial into the conference early, overheard the producers mention the call’s secret code, and then used it to become one of the guest speakers. Myers then proceeded to caustically poke holes in their anti-evolution narrative with a dial-in audience listening.

This is the zeitgeist of today’s skeptics, fighting fire with fire. But not everyone likes the approach. At the 2010 TAM, astronomer and skeptic Phil Plait, who runs the website BadAstronomy.com, gave a little talk entitled, “Don’t Be a Dick.”

“There’ve been some alarming developments in the way skepticism is being done,” Plait told a large audience. “The tone of what we’re doing is decaying. It seems that vitriol and venom are on the rise, and I’m unhappy about that.”

Plait’s speech caused a firestorm in the community. People took it personally. A lot of the ensuing rage was indicative of Internet culture itself—explosive and reactionary. Such was the outcry that Plait was compelled to clarify his position weeks and even months later. “I did not say we should back down when confronted,” he wrote on his blog. “I did not say we shouldn’t be angry. We need our anger, our strength, and our passion. However, being a dick,” he maintained, “almost always works against the bigger goal of swaying the most people we can.”

Aggressive atheists and skeptics like Myers and Dawkins disagree that there’s no place for confrontational voices. Others, like Steve Novella, claim a middle ground:

“I don’t know that anyone has the best empirical answer to promoting skepticism. I’m tolerant when people choose to promote it in their own way. My own approach is to take a more soft-spoken angle, not that I pull punches. And yes, we get snarky at times. But I think there’s room in the movement for any number of approaches, and frankly, some things deserve to be ridiculed if they’re so far beyond the pale. I can’t disagree with that.”

How skeptics engage with each other is at least as important as how they engage general audiences. Perhaps the most inflammatory example within the movement today is an incident known as “Elevatorgate.”

Rebecca Watson, founder of Skepchick, is a feminist skeptic and prolific atheist activist. Her website was founded, in her own words, as “an organization dedicated to promoting skepticism and critical thinking among women around the world.” Watson promotes skepticism through hard-hitting commentary and ironic playfulness, and she travels the world to do just that. From co-hosting the SGU to having published a Skepchick pin-up calendar to posting frequently on YouTube, Watson is incredibly active.

Elevatorgate happened in 2011, while Watson was at a meeting in Dublin. She sat on a panel during which she discussed the sexism and misogyny she’d experienced first-hand in the atheist movement. Hours after the talk, she was in her hotel elevator when the only other passenger—an unidentified man—asked her if she’d be interested in going back to his hotel room for coffee. She declined. Later, Watson made a video blog in which she casually mentioned the encounter. “Just a word to the wise here, guys: Don’t do that. I was a single woman in a foreign country at 4 a.m. in a hotel elevator.”

Little might have come of it had Richard Dawkins not provided an online response. Addressing a fictional Muslim woman, Dawkins wrote: “Yes, yes, I know you had your genitals mutilated with a razor blade, and… yawn… don’t tell me yet again, I know you aren’t allowed to drive a car, and you can’t leave the house without a male relative, and your husband is allowed to beat you, and you’ll be stoned to death if you commit adultery. But stop whining, will you. Think of the suffering your poor American sisters have to put up with. Only this week I heard of one, she calls herself Skepchick, and do you know what happened to her? A man in a hotel elevator invited her back to his room for coffee.”

The ensuing eruption was an outright war, not merely between the sexes, but along numerous fracture lines. Ardent Skepchick fans called for the “elevator guy’s” head, while others maintained that in a free society men and women can propose coffee dates, while still others said it wasn’t the offer, but rather the place and time that were the issue.

Commenting months later, Watson said that she had heard from other women who felt marginalized and sexualized at skeptical events. “I’ve had more and more messages from men who tell me what they’d like to do to me, sexually,” she wrote. “More and more men touching me without permission at conferences. More and more threats of rape from those who don’t agree with me, even from those who consider themselves skeptics and atheists. I didn’t call for an end to sex. I didn’t accuse the man in my story of rape. I didn’t say all men are monsters.”

As with Plait, the incident cycled through fits of Internet rage, but also got people talking about aspects of the movement that had previously been in the dark.

Skepticism Today and Tomorrow

Looking outward, more than ever before, today’s skepticism is about action and collaboration on an increasingly global scale.

Take JREF Field Coordinator Brian Thompson. A typical week for him involves acting as liaison with grassroots skeptic groups, creating educational modules for teachers wishing to discuss skepticism in the classroom, sending out press releases on issues of skeptical concern, and even coordinating with other groups that aren’t necessarily skeptical in nature.

“One of our most recent battles is to fight against shark finning,” Thompson reports. “There’s an entire industry where sharks are caught, stripped of their fins, and thrown back to die. Obviously this is a concern for animal welfare and conservation groups; where we come in is the fact that these shark fins are being ground up and sold as anti-cancer medicine.”

Many skeptics see dubious alternative medicine and homeopathy claims as a chief battleground. The Merseyside Skeptics Society of the UK coordinates with the JREF in an annual 10:23 Homeopathy Challenge. The purpose? Getting participants to “overdose” on homeopathic remedies.

Often confused by the general public as part of the herbal supplement or natural foods industry, homeopathic remedies instead operate on a system of belief: that selling wildly diluted substances is a good way to treat disease. “We’ve done major media campaigns to educate people about this,” says Thompson. “We also petition stores to stop selling these products.”

Homeopathy is predicated on key beliefs, including the notion that a problem (like insomnia) can be treated with something that induces wakefulness (like caffeine). Homeopathy also maintains that a single drop of a substance (say a drop of caffeine) can be diluted in ninety-nine drops of water, shaken, and then a drop from that mixture can be put in another ninety-nine drops of water, and so on. The homeopathic position is that this systematic dilution actually causes the opposite effect: a single drop of caffeine becomes more potent than ever. Needless to say, there is no scientific data to support such a conclusion. Hence, the 10:23 Challenge takes direct aim at this belief by having members willfully drink “dangerously high” levels of these diluted substances; in 2010, protestors from seventy cities in thirty countries participated. No one’s died yet.

One of the most recognized voices in skepticism is that of Michael Shermer, the founding publisher of Skeptic magazine, executive director of the Skeptics Society, and monthly columnist for Scientific American. Shermer sees skepticism on the rise.

“Social media has been huge for us,” he says. “The movement has grown, and the activities of so many skeptical groups has helped legitimize it into more mainstream circles.”

In addition to his publishing and lecturing, Shermer currently teaches a ten-week course on skepticism at Chapman University. No subject is off-limits: Bigfoot, Holocaust denial, UFOs, vaccine controversies, and more. “My goal isn’t to tell students what to think or what to believe,” he says, “but to get them thinking critically about subjects.”

Shermer is also launching a powerful educational resource for other schools interested in skepticism. A seemingly endless series of modules, PDFs, skeptical reading material, syllabi, PowerPoint presentations, and even magic tricks are available at Skeptic.com, further highlighting the benefits of the Information Age to skeptics anywhere in the world. “It’s about teaching our kids to be good scientific thinkers,” Shermer says.

And in this regard, the new skepticism is poised on the edge of a cultural shift. Today, science is embedded in our social patterns. Information is a collective fetish, and it has provided language to describe things once seen as magical and off-limits. The human genome is captured in a single gigabyte, while the tidal impact of data is radically changing all fields of human endeavor—from medicine to transportation to engineering to environmentalism.

Back in Sin City, the TAM crowd retires from another successful meeting. The halls, lobby, and parking lot of the hotel are buzzing with discussion. A gang of high-profile politicians has made another attack on the scientific establishment. Another celebrity has condemned evolution and homosexuals. Another psychic is forecasting the end of the world. For these skeptics, it seems the fight is far from over.

And from the looks on their faces, they’re just fine with that.