Why people believe weird things: pseudoscience, superst.i.tion, and other confusions of our time / Michael Shermer.

Prologue.

Next on Oprah.

On Monday, October 2, 1995, for the first time in its ten-year history, the Oprah Winfrey Show Oprah Winfrey Show offered a psychic as the featured guest. She was Rosemary Altea (a nom de plume), who claims to communicate with the dead. Her book about this extraordinary a.s.sertion- offered a psychic as the featured guest. She was Rosemary Altea (a nom de plume), who claims to communicate with the dead. Her book about this extraordinary a.s.sertion- The Eagle and the Rose: A Remarkable True Story- The Eagle and the Rose: A Remarkable True Story--had been on the New York Times New York Times and the and the Wall Street Journal Wall Street Journal best-seller lists for several weeks. ("The eagle" is a Native American Indian-Altea's spirit guide-and Altea is "the rose.") Oprah began with the disclaimer that she was doing this show only because several trusted friends had described Altea as the cla.s.s act of the psychic world. Next, the producers rolled several minutes of video, taped the previous day, that showed Altea working a small audience in a Chicago flat, asking countless questions, making numerous generalizations, and providing occasional specifics about their dearly departed. Altea then began working the audience in the studio. "Did someone here lose a loved one in a drowning accident?" "I see a man standing behind you." "Was there a boat involved?" And so on. best-seller lists for several weeks. ("The eagle" is a Native American Indian-Altea's spirit guide-and Altea is "the rose.") Oprah began with the disclaimer that she was doing this show only because several trusted friends had described Altea as the cla.s.s act of the psychic world. Next, the producers rolled several minutes of video, taped the previous day, that showed Altea working a small audience in a Chicago flat, asking countless questions, making numerous generalizations, and providing occasional specifics about their dearly departed. Altea then began working the audience in the studio. "Did someone here lose a loved one in a drowning accident?" "I see a man standing behind you." "Was there a boat involved?" And so on.

Unlike most psychics I have seen, Altea was bombing. The audience was not feeding her the cues she needed to "divine" her information. Finally, well into the program, she struck pay dirt. Calling out to a middle-aged woman partially hidden behind a studio camera, Altea said the woman had lost her mother to cancer. The woman screamed and started crying. Furthermore, Altea noted, the young man next to the woman was her son, who was troubled by school and career decisions. He acknowledged the observation and recounted his tale of woe. The audience was stunned. Oprah was silenced. Altea pumped out more details and predictions. After the taping, one woman stood up and announced that she had come to the studio to debunk Altea but was now a believer.

Enter the skeptic. Three days before the taping of the show, one of Oprah's producers called me. Shocked that the publisher of Skeptic Skeptic magazine had never heard of Rosemary Altea, the producer was preparing to call someone else to do the show when I told her, sight unseen, exactly how Altea operated. The producer mailed me an airline ticket. In my allotted few minutes, I explained that what the audience had just witnessed could be seen at the Magic Castle in Hollywood on any night that a mentalist who knows how to work a crowd is appearing. By "work," I mean the time-proven technique of cold-reading, where the mentalist asks general questions until he or she finds someone who gives generous doses of feedback. Continued questioning eventually finds targets. "Was it lung cancer? Because I'm getting a pain here in the chest." Subject says, "It was a heart attack." "Heart attack? Yes, that explains the chest pains." Or, "I'm sensing a drowning. Was there a boat involved? I'm seeing a boat of some kind on a body of water, maybe a lake or river." And so on. In an audience of two hundred fifty people; every major cause of death will be represented. magazine had never heard of Rosemary Altea, the producer was preparing to call someone else to do the show when I told her, sight unseen, exactly how Altea operated. The producer mailed me an airline ticket. In my allotted few minutes, I explained that what the audience had just witnessed could be seen at the Magic Castle in Hollywood on any night that a mentalist who knows how to work a crowd is appearing. By "work," I mean the time-proven technique of cold-reading, where the mentalist asks general questions until he or she finds someone who gives generous doses of feedback. Continued questioning eventually finds targets. "Was it lung cancer? Because I'm getting a pain here in the chest." Subject says, "It was a heart attack." "Heart attack? Yes, that explains the chest pains." Or, "I'm sensing a drowning. Was there a boat involved? I'm seeing a boat of some kind on a body of water, maybe a lake or river." And so on. In an audience of two hundred fifty people; every major cause of death will be represented.

The principles of cold-reading are simple: start general (car accidents, drownings, heart attacks, cancer), keep it positive ("He wants you to know he loves you very much," "She says to tell you that she is no longer suffering," "His pain is gone now"), and know that your audience will remember the hits and forget the misses ("How did she know it was cancer?" "How did he get her name?"). But how did Rosemary Altea, without asking, know that the woman's mother had died of cancer and that her son was having doubts about his career? For Oprah, two hundred fifty studio eyewitnesses, and millions of television viewers, Altea appeared to have a direct line to the spirit world.

The explanation is very much of this world, however. Mentalists call this a hot reading where you actually obtain information on your subject ahead of time. Earlier that day, I had shared a limousine from the hotel to the studio with several guests on the show, two of whom were this woman and her son. During the drive, they mentioned that they had met with Altea before and had been invited by Oprah's producers to share their experience with the television audience. Since almost no one knew this little fact, Altea could use her prior knowledge of the woman and her son to s.n.a.t.c.h victory from the jaws of defeat. Naturally I pointed out this fact but, incredibly, the woman denied having previously met with Altea and the exchange was simply edited out of the show.

I doubt that Altea deliberately deceives her audiences by consciously using cold-reading techniques. Rather, I believe she innocently developed a belief in her own "psychic powers" and innocently learned cold-reading by trial and error. She says it all began in November 1981, when "I woke early one morning to find him standing by the bed, looking down at me. Although I was still half asleep, I knew he was no apparition, no specter in the night" (1995, p. 56). From there, as her book reveals, it was a long process of becoming open to the possibility of a spirit world through what psychologists call hypnopompic hallucinations hypnopompic hallucinations-visions of ghosts, aliens, or loved ones that occur as one emerges from deep sleep-and mystical interpretations of unusual experiences.

But whether we are talking about rats pressing a bar to get food or humans playing a Las Vegas slot machine, it only takes an occasional hit to keep them coming back for more. Altea's belief and behavior were shaped by operant conditioning on a variable-ratio schedule of reinforcement-lots of misses but just enough hits to shape and maintain the behavior. Positive feedback in the form of happy customers paying up to $200 per session was a mechanism sufficient to reinforce her own belief in her powers and to encourage her to hone her mentalist skills.

The same explanation probably holds for the master of cold-reading in the psychic world-James Van Praagh-who wowed audiences for months on NBC's New Age talk show The Other Side, The Other Side, until he was debunked on until he was debunked on Unsolved Mysteries. Unsolved Mysteries. Here's how. I was asked to sit in a room with nine other people. Van Praagh was asked to do a reading on each of us, all of whom had lost a loved one. I worked closely with the producers to ensure that Van Praagh would have no prior knowledge of any of us. (In addition to subscribing to demographic marketing journals so that they can make statistically educated guesses about subjects based on age, gender, race, and residence, mentalists have been known to go as far as running a name through a detective agency.) His readings would have to be "cold" indeed. The session lasted eleven hours and included several snack breaks, an extended lunch break, and numerous pauses in the filming while technicians reloaded the cameras. Van Praagh opened with a half-hour of New Age music and astrological mumbo jumbo to "prepare" us for our journey to the other side. His mannerisms were somewhat effeminate, and he came off as quite empathic, as if he could "feel our pain." Here's how. I was asked to sit in a room with nine other people. Van Praagh was asked to do a reading on each of us, all of whom had lost a loved one. I worked closely with the producers to ensure that Van Praagh would have no prior knowledge of any of us. (In addition to subscribing to demographic marketing journals so that they can make statistically educated guesses about subjects based on age, gender, race, and residence, mentalists have been known to go as far as running a name through a detective agency.) His readings would have to be "cold" indeed. The session lasted eleven hours and included several snack breaks, an extended lunch break, and numerous pauses in the filming while technicians reloaded the cameras. Van Praagh opened with a half-hour of New Age music and astrological mumbo jumbo to "prepare" us for our journey to the other side. His mannerisms were somewhat effeminate, and he came off as quite empathic, as if he could "feel our pain."

With most of us, Van Praagh figured out the cause of death through a technique I had not seen before. He would rub either his chest or his head and say "I'm getting a pain here," watching the subject's face for feedback. After the third time, it suddenly struck me why: most people die from heart, lung, or brain failure, regardless of the specific cause (such as, heart attack, stroke, lung cancer, drowning, falling, or automobile accident). With several subjects, he got nothing and said so. "I'm not getting anything. I'm sorry. If it's not there, it's not there." For most of us, however, he got many details as well as the specific cause of death-but not without lots and lots of misses. For the first two hours, I kept track of the number of "no's" and negative head shakes. There were well over a hundred misses for only a dozen or so hits. Given time and enough questions, anyone with a little training could become sensitive enough to do exactly what Van Praagh does.

I also noticed that during the film-changing breaks, Van Praagh would make small talk with the people in the room. "Who are you here for?" he asked one woman. She told him it was her mother. Several readings later, Van Praagh turned to the woman and said, "I see a woman standing behind you. Is that your mother?" At all times he kept it positive. There was redemption for all-our loved ones forgive us for any wrongdoing; they still love us; they suffer no more; they want us to be happy. What else would he say? "Your father wants you to know that he will never forgive you for wrecking his car"? One young woman's husband had been run over by a car. Van Praagh told her, "He wants you to know you will be married again." It turned out that she was engaged to be married, and, of course, she credited Van Praagh with a hit. But, as I explained on camera, Van Praagh said nothing of the sort. He gave his usual positive generalization with no specifics. He did not tell her she was presently engaged to be married. He just said that someday she would marry again. So what? His alternative was to tell the young lady that she would be a lonely widow the rest of her life, which is both statistically unlikely and depressing.

The most dramatic moment of the day came when Van Praagh got the name of a couple's son who had been killed in a drive-by shooting. "I'm seeing the letter K," he proclaimed. "Is it Kevin or Ken?" The mother responded tearfully in a cracking voice, "Yes, Kevin." We were all astonished. Then I noticed around the mother's neck a large, heavy ring with the letter "K" inscribed in diamonds on a black background. Van Praagh denied having seen the ring when I pointed it out on camera. In eleven hours of taping and small talk during breaks, surely he saw the ring. I did, and he's the professional.

The reactions of the audience members I found even more intriguing than the mentalist techniques of Altea and Van Praagh. Anyone can learn cold-reading techniques in half an hour. They work because subjects want want them to work. Every person at the them to work. Every person at the Unsolved Mysteries Unsolved Mysteries taping except me wanted Van Praagh to be successful. They came there to speak with their loved ones. In the post-session interviews, all nine subjects gave Van Praagh a positive evaluation, even the few for whom he obviously missed. One woman's daughter had been raped and murdered many years ago, and the police still have no clues to the perpetrator or even to how the crime was committed. The mother had been making the rounds on talk shows, desperately seeking help in finding her daughter's killer. Van Praagh went to her heart like salt into a wound. He reconstructed the murder scene, describing a man on top of the young woman raping her and stabbing her with a knife, and left this grieving mother in tears. (Van Praagh was credited by all with getting this cause of death correct, but earlier, in the morning session, while he was fishing around by rubbing his chest and head, the mother slashed her fingers across her throat, indicating that her daughter's throat had been cut. Everyone but me had forgotten this clue by the time Van Praagh used it.) taping except me wanted Van Praagh to be successful. They came there to speak with their loved ones. In the post-session interviews, all nine subjects gave Van Praagh a positive evaluation, even the few for whom he obviously missed. One woman's daughter had been raped and murdered many years ago, and the police still have no clues to the perpetrator or even to how the crime was committed. The mother had been making the rounds on talk shows, desperately seeking help in finding her daughter's killer. Van Praagh went to her heart like salt into a wound. He reconstructed the murder scene, describing a man on top of the young woman raping her and stabbing her with a knife, and left this grieving mother in tears. (Van Praagh was credited by all with getting this cause of death correct, but earlier, in the morning session, while he was fishing around by rubbing his chest and head, the mother slashed her fingers across her throat, indicating that her daughter's throat had been cut. Everyone but me had forgotten this clue by the time Van Praagh used it.) After the Unsolved Mysteries Unsolved Mysteries taping, it became clear that everyone but me was impressed with Van Praagh. The others challenged me to explain all his amazing hits. When I finally told them who I am, what I was doing there, and how cold-reading works, most were uninterested but several walked away. One woman glared at me and told me it was "inappropriate" to destroy these people's hopes during their time of grief. taping, it became clear that everyone but me was impressed with Van Praagh. The others challenged me to explain all his amazing hits. When I finally told them who I am, what I was doing there, and how cold-reading works, most were uninterested but several walked away. One woman glared at me and told me it was "inappropriate" to destroy these people's hopes during their time of grief.

Herein lies the key to understanding this phenomenon. Life is contingent and filled with uncertainties, the most frightening of which is the manner, time, and place of our own demise. For a parent, an even worse fear is the death of one's child, which makes those who have suffered such a loss especially vulnerable to what "psychics" offer. Under the pressure of reality, we become credulous. We seek rea.s.suring certainties from fortune-tellers and palm-readers, astrologers and psychics. Our critical faculties break down under the onslaught of promises and hopes offered to a.s.suage life's great anxieties. Wouldn't it be marvelous if we did not really die? Wouldn't it be wonderful if we could speak with our lost loved ones again? Of course it would. Skeptics are no different from believers when it comes to such desires. This is an ancient human drive. In a world where one's life was as uncertain as the next meal, our ancestors all over the globe developed beliefs in an afterlife and spirit world. So, when we are vulnerable and afraid, the provider of hope has only to make the promise of an afterlife and offer the flimsiest of proofs. Human credulity will do the rest, as poet Alexander Pope observed in his 1733 Essay on Man Essay on Man (Epistle I, 1. 95): (Epistle I, 1. 95):

Hope springs eternal in the human breast; Man never Is, but always To be blest. The soul, uneasy, and confin 'd from home, Rests and expatiates in a life to come.

This hope is what drives all of us-skeptics and believers alike-to be compelled by unsolved mysteries, to seek spiritual meaning in a physical universe, desire immortality, and wish that our hopes for eternity may be fulfilled. It is what pushes many people to spiritualists, New Age gurus, and television psychics, who offer a Faustian bargain: eternity in exchange for the willing suspension of disbelief (and usually a contribution to the provider's coffers).

But hope springs eternal for scientists and skeptics as well. We are fascinated by mysteries and awed by the universe and the ability of humans to achieve so much in so little time. We seek immortality through our c.u.mulative efforts and lasting achievements; we too wish that our hopes for eternity might be fulfilled.

This book is about people who share similar beliefs and hopes yet pursue them by very dissimilar methods. It is about the distinction between science and pseudoscience, history and pseudohistory, and the difference it makes. Although each chapter can be read independently, c.u.mulatively they show the allure of psychic power and extrasensory perception, UFOs and alien abductions, ghosts and haunted houses. But more than this, the book deals with controversies not necessarily on the margins of society which may have pernicious social consequences: creation-science and biblical literalism, Holocaust denial and freedom of speech, race and IQ, political extremism and the radical right, modern witch crazes prompted by moral panics and ma.s.s hysterias, including the recovered memory movement, Satanic ritual abuse, and facilitated communication. Here the difference in thinking makes all the difference.

But more than this-much more-the book is a celebration of the scientific spirit and of the joy inherent in exploring the world's great mysteries even when final answers are not forthcoming. The intellectual journey matters, not the destination. We live in the age of science. It is the reason pseudosciences flourish-pseudoscientists know that their ideas must at least appear appear scientific because science is the touchstone of truth in our culture. Most of us harbor a type of faith in science, a confidence that somehow science will solve our major problems-AIDS, overpopulation, cancer, pollution, heart disease, and so on. Some even entertain scientistic visions of a future without aging, where we will ingest nanotechnological computers that will repair cells and organs, eradicate life-threatening diseases, and maintain us at our chosen age. scientific because science is the touchstone of truth in our culture. Most of us harbor a type of faith in science, a confidence that somehow science will solve our major problems-AIDS, overpopulation, cancer, pollution, heart disease, and so on. Some even entertain scientistic visions of a future without aging, where we will ingest nanotechnological computers that will repair cells and organs, eradicate life-threatening diseases, and maintain us at our chosen age.

So hope springs eternal not just for spiritualists, religionists, New Agers, and psychics, but for materialists, atheists, scientists, and, yes, even skeptics. The difference is in where we find hope. The first group uses science and rationality when convenient, and dumps them when they are not. For this group, any thinking will do, as long as it fulfills that deeply rooted human need for certainty. Why?

Humans evolved the ability to seek and find connections between things and events in the environment (snakes with rattles should be avoided), and those who made the best connections left behind the most offspring. We are their descendants. The problem is that causal thinking is not infallible. We make connections whether they are there or not. These misidentifications come in two varieties: false negatives get you killed (snakes with rattles are okay); false positives merely waste time and energy (a rain dance will end a drought). We are left with a legacy of false positives-hypnopompic hallucinations become ghosts or aliens; knocking noises in an empty house indicate spirits and poltergeists; shadows and lights in a tree become the Virgin Mary; random mountain shadows on Mars are seen as a face constructed by aliens. The belief influences the perception. "Missing" fossils in geological strata become evidence of divine creation. The lack of a written order by Hitler to exterminate the Jews means that perhaps there was no such order ... or no such extermination. Coincidental configurations of subatomic particles and astronomical structures indicate an intelligent designer of the universe. Vague feelings and memories evoked through hypnosis and guided-imagery in therapy evolve into crystal-clear memories of childhood s.e.xual abuse, even when no corroborating evidence exists.

Scientists have their false positives-but the methods of science were specifically designed to weed them out. Had the cold fusion findings, to take a recent spectacular example of a false positive, not been made so public before corroboration from other scientists, they would have been nothing out of the ordinary. This is precisely how science progresses- countless identified false negatives and false positives. The public, however, does not usually hear about them because negative findings are not usually published. That silicon breast implants might cause serious health problems was big news; that there has been no corroborative and replicable scientific evidence that they do has gone almost unnoticed.

What, then, you may ask, does it mean to be a skeptic? Some people believe that skepticism is rejection of new ideas or, worse, they confuse skeptic skeptic with with cynic cynic and think that skeptics are a bunch of grumpy curmudgeons unwilling to accept any claim that challenges the status quo. This is wrong. Skepticism is a provisional approach to claims. and think that skeptics are a bunch of grumpy curmudgeons unwilling to accept any claim that challenges the status quo. This is wrong. Skepticism is a provisional approach to claims. Skepticism is a method, not a position. Skepticism is a method, not a position. Ideally, skeptics do not go into an investigation closed to the possibility that a phenomenon might be real or that a claim might be true. For example, when I investigated the claims of the Holocaust deniers, I ended up being skeptical of these skeptics (see chapters 13 and 14). In the case of recovered memories, I came down on the side of the skeptics (see chapter 7). One may be skeptical of a belief or of those who challenge it. Ideally, skeptics do not go into an investigation closed to the possibility that a phenomenon might be real or that a claim might be true. For example, when I investigated the claims of the Holocaust deniers, I ended up being skeptical of these skeptics (see chapters 13 and 14). In the case of recovered memories, I came down on the side of the skeptics (see chapter 7). One may be skeptical of a belief or of those who challenge it.

The a.n.a.lyses in this book explain in three tiers why people believe weird things: (1) because hope springs eternal; (2) because thinking can go wrong in general ways; (3) because thinking can go wrong in particular ways. I mix specific examples of "weird beliefs" with general principles about what we can learn from examining such beliefs. To this end, I have taken Stephen Jay Gould's style as a model for a healthy blend of the particular and the universal, the details and the big picture; and as inspiration James Randi's mission to understand some of the more perplexing mysteries of our age and ages past.

In the five years since we founded the Skeptics Society and Skeptic Skeptic magazine, my partner, friend, and wife, Kim Ziel Shermer, has provided countless hours of feedback during meals, while driving in the car and riding bikes, and on our daily jaunt up the mountain with the dogs and our daughter, Devin. My other magazine, my partner, friend, and wife, Kim Ziel Shermer, has provided countless hours of feedback during meals, while driving in the car and riding bikes, and on our daily jaunt up the mountain with the dogs and our daughter, Devin. My other Skeptic Skeptic partner, Pat Linse, has proved to be far more than just a brilliant art director. She is one of a rare species, an artistic and scientific polymath, whose prolific reading (she doesn't own a television) enables her not only to converse on virtually any subject but to make original and constructive contributions to the skeptic movement. partner, Pat Linse, has proved to be far more than just a brilliant art director. She is one of a rare species, an artistic and scientific polymath, whose prolific reading (she doesn't own a television) enables her not only to converse on virtually any subject but to make original and constructive contributions to the skeptic movement.

I also wish to acknowledge those who have been most helpful in producing Skeptic Skeptic magazine and putting on our lecture series at Caltech, without which this book would not exist. Jaime Botero has been there with me since I taught the evening course in introductory psychology at Glendale College a decade ago. Diane Knudtson has worked nearly every Skeptics Society lecture at Caltech for nothing more than a meal and food for thought. Brad Davies has produced videos of every lecture and provided valuable feedback on the speakers' many and diverse ideas. Jerry Friedman constructed our database, organized the Skeptics Society survey, and provided valuable information on the animal rights movement. Terry Kirker continues to contribute to the promotion of science and skepticism in her own unique way. magazine and putting on our lecture series at Caltech, without which this book would not exist. Jaime Botero has been there with me since I taught the evening course in introductory psychology at Glendale College a decade ago. Diane Knudtson has worked nearly every Skeptics Society lecture at Caltech for nothing more than a meal and food for thought. Brad Davies has produced videos of every lecture and provided valuable feedback on the speakers' many and diverse ideas. Jerry Friedman constructed our database, organized the Skeptics Society survey, and provided valuable information on the animal rights movement. Terry Kirker continues to contribute to the promotion of science and skepticism in her own unique way.

Most of the chapters began as essays originally published in Skeptic Skeptic magazine, which I edit. Skeptical readers may then reasonably ask, Who edits the editor? Who is skeptical of the skeptic? Every essay in this volume has been read and edited by my publisher's editors, Elizabeth Knoll, Mary Louise Byrd, and Mich.e.l.le Bonnice; by my partners, Kim and Pat; by one or more of magazine, which I edit. Skeptical readers may then reasonably ask, Who edits the editor? Who is skeptical of the skeptic? Every essay in this volume has been read and edited by my publisher's editors, Elizabeth Knoll, Mary Louise Byrd, and Mich.e.l.le Bonnice; by my partners, Kim and Pat; by one or more of Skeptic Skeptic magazine's contributing editors; and, where appropriate, by a member of magazine's contributing editors; and, where appropriate, by a member of Skeptic Skeptic magazine's editorial board or by an expert in the field. For this, I heartily thank David Alexander, Clay Drees, Gene Friedman, Alex Grobman, Diane Halpern, Steve Harris, Gerald Larue, Jim Lippard, Betty McCollister, Tom McDonough, Paul McDowell, Tom Mclver, Sara Meric, John Mosley, Richard Olson, D'art Phares, Donald Prothero, Rick Shaffer, Elie Shneour, Brian Siano, Jay Snelson, Carol Tavris, Kurt Wochholtz, and especially Richard Hardison, Bernard Leikind, Frank Miele, and Frank Sulloway, for not allowing friendship to get in the way of brutal honesty when editing my essays. At W. H. Freeman I wish to thank Simone Cooper who brilliantly organized my national book tour and made it a joy rather than a ch.o.r.e; Peter McGuigan for bringing the book to audio so people can hear it as well as read it; John Michel for his critical feedback on this and the transition to my next book, magazine's editorial board or by an expert in the field. For this, I heartily thank David Alexander, Clay Drees, Gene Friedman, Alex Grobman, Diane Halpern, Steve Harris, Gerald Larue, Jim Lippard, Betty McCollister, Tom McDonough, Paul McDowell, Tom Mclver, Sara Meric, John Mosley, Richard Olson, D'art Phares, Donald Prothero, Rick Shaffer, Elie Shneour, Brian Siano, Jay Snelson, Carol Tavris, Kurt Wochholtz, and especially Richard Hardison, Bernard Leikind, Frank Miele, and Frank Sulloway, for not allowing friendship to get in the way of brutal honesty when editing my essays. At W. H. Freeman I wish to thank Simone Cooper who brilliantly organized my national book tour and made it a joy rather than a ch.o.r.e; Peter McGuigan for bringing the book to audio so people can hear it as well as read it; John Michel for his critical feedback on this and the transition to my next book, Why People Believe in G.o.d. Why People Believe in G.o.d. A special thanks to Sloane Lederer who maintained the progress of the publishing and promotion of this book throughout numerous personnel changes at the publisher, as well as for understanding the deeper importance of what we skeptics are trying to accomplish through writing books such as this. Thanks to my agents Katinka Matson and John Brockman, and their foreign rights director Linda Wollenberger, for helping to bring about the book in this and other languages. Finally, Bruce Mazet has made it possible for the Skeptics Society, A special thanks to Sloane Lederer who maintained the progress of the publishing and promotion of this book throughout numerous personnel changes at the publisher, as well as for understanding the deeper importance of what we skeptics are trying to accomplish through writing books such as this. Thanks to my agents Katinka Matson and John Brockman, and their foreign rights director Linda Wollenberger, for helping to bring about the book in this and other languages. Finally, Bruce Mazet has made it possible for the Skeptics Society, Skeptic Skeptic magazine, and Millennium Press to battle ignorance and misunderstanding; he has pushed us well beyond what I ever dreamed we were capable of accomplishing. magazine, and Millennium Press to battle ignorance and misunderstanding; he has pushed us well beyond what I ever dreamed we were capable of accomplishing.

In his 1958 masterpiece, The Philosophy of Physical Science, The Philosophy of Physical Science, physicist and astronomer Sir Arthur Stanley Eddington asked about observations made by scientists, physicist and astronomer Sir Arthur Stanley Eddington asked about observations made by scientists, "Quis custodiet ipsos custodes?-Who will observe the observers?" "Quis custodiet ipsos custodes?-Who will observe the observers?" "The epistemologist," answered Eddington. "He watches them to see what they really observe, which is often quite different from what they say they observe. He examines their procedure and the essential limitations of the equipment they bring to their task, and by so doing becomes aware beforehand of limitations to which the results they obtain will have to conform" (1958, p. 21). Today the observers' observers are the skeptics. But who will observe the skeptics? You. So have at it and have fun. "The epistemologist," answered Eddington. "He watches them to see what they really observe, which is often quite different from what they say they observe. He examines their procedure and the essential limitations of the equipment they bring to their task, and by so doing becomes aware beforehand of limitations to which the results they obtain will have to conform" (1958, p. 21). Today the observers' observers are the skeptics. But who will observe the skeptics? You. So have at it and have fun.

PART 1.

SCIENCE AND SKEPTICISM.

Science is founded on the conviction that experience, effort, and reason are valid; magic on the belief that hope cannot fail nor desire deceive.

-Branislaw Malinowski, Magic, Science, and Religion, Magic, Science, and Religion, 1948 1948

1.

I Am Therefore I Think

A Skeptic's Manifesto

On the opening page of his splendid little book To Know a Fly, To Know a Fly, biologist Vincent Dethier makes this humorous observation about how children grow up to be scientists: "Although small children have taboos against stepping on ants because such actions are said to bring on rain, there has never seemed to be a taboo against pulling off the legs or wings of flies. Most children eventually outgrow this behavior. Those who do not either come to a bad end or become biologists" (1962, p. 2). In their early years, children are knowledge junkies, questioning everything in their purview, though exhibiting little skepticism. Most never learn to distinguish between skepticism and credulity. It took me a long time. biologist Vincent Dethier makes this humorous observation about how children grow up to be scientists: "Although small children have taboos against stepping on ants because such actions are said to bring on rain, there has never seemed to be a taboo against pulling off the legs or wings of flies. Most children eventually outgrow this behavior. Those who do not either come to a bad end or become biologists" (1962, p. 2). In their early years, children are knowledge junkies, questioning everything in their purview, though exhibiting little skepticism. Most never learn to distinguish between skepticism and credulity. It took me a long time.

In 1979, unable to land a full-time teaching job, I found work as a writer for a cycling magazine. The first day on the job, I was sent to a press conference held in honor of a man named John Marino who had just ridden his bicycle across America in a record 13 days, 1 hour, 20 minutes. When I asked him how he did it, John told me about special vegetarian diets, megavitamin therapy, fasting, colonics, mud baths, iridology, cytotoxic blood testing, Rolfing, acupressure and acupuncture, chiropractic and ma.s.sage therapy, negative ions, pyramid power, and a host of weird things with which I was unfamiliar. Being a fairly inquisitive fellow, when I took up cycling as a serious sport I thought I would try these things to see for myself whether they worked. I once fasted for a week on nothing but a strange mixture of water, cayenne pepper, garlic, and lemon. At the end of the week, John and I rode from Irvine to Big Bear Lake and back, some seventy miles each way. About halfway up the mountain I collapsed, violently ill from the concoction. John and I once rode out to a health spa near Lake Elsinore for a mud bath that was supposed to suck the toxins out of my body. My skin was dyed red for a week. I set up a negative ion generator in my bedroom to charge the air to give me more energy. It turned the walls black with dust. I got my iris read by an iridologist, who told me that the little green flecks in my eyes meant something was wrong with my kidneys. To this day my kidneys are functioning fine.

I really got into cycling. I bought a racing bike the day after I met John and entered my first race that weekend. I did my first century ride (100 miles) a month later, and my first double century later that year. I kept trying weird things because I figured I had nothing to lose and, who knows, maybe they would increase performance. I tried colonics because supposedly bad things clog the plumbing and thus decrease digestive efficiency, but all I got was an hour with a hose in a very uncomfortable place. I installed a pyramid in my apartment because it was supposed to focus energy. All I got were strange looks from guests. I starting getting ma.s.sages, which were thoroughly enjoyable and quite relaxing. Then my ma.s.sage therapist decided that "deep tissue" ma.s.sage was best to get lactic acid out of the muscles. That wasn't so relaxing. One guy ma.s.saged me with his feet. That was even less relaxing. I tried Rolling, which is really really deep tissue ma.s.sage. That was so painful that I never went back. deep tissue ma.s.sage. That was so painful that I never went back.

In 1982 John and I and two other men competed in the first Race Across America, the 3,000-mile, nonstop, transcontinental bike race from Los Angeles to New York. In preparation, we went for cytotoxic blood testing because it was supposed to detect food allergies that cause blood platelets to clump together and block capillaries, thus decreasing blood flow. By now we were a little skeptical of the truth of these various claims, so we sent in one man's blood under several names. Each sample came back with different food allergies, which told us that there was a problem with their testing, not with our blood. During the race, I slept with an "Electro-Acuscope," which was to measure my brain waves and put me into an alpha state for better sleeping. It was also supposed to rejuvenate my muscles and heal any injuries. The company swore that it helped Joe Montana win the Super Bowl. Near as I can figure, it was totally ineffective.

The Electro-Acuscope was the idea of my chiropractor. I began visiting a chiropractor not because I needed one but because I had read that energy flows through the spinal cord and can get blocked at various places. I discovered that the more I got adjusted, the more I needed to get adjusted because my neck and back kept going "out." This went on for a couple of years until I finally quit going altogether, and I've never needed a chiropractor since.

All told, I raced as a professional ultra-marathon cyclist for ten years, all the while trying anything and everything (except drugs and steroids) that might improve my performance. As the Race Across America got bigger-it was featured for many years on ABC's Wide World of Sports Wide World of Sports-I had many offers to try all sorts of things, which I usually did. From this ten-year experiment with a subject pool of one, I drew two conclusions: nothing increased performance, alleviated pain, or enhanced well-being other than long hours in the saddle, dedication to a consistent training schedule, and a balanced diet; and it pays to be skeptical. But what does it mean to be skeptical?

What Is a Skeptic?

I became a skeptic on Sat.u.r.day, August 6, 1983, on the long, climbing road to Loveland Pa.s.s, Colorado. It was Day 3 of the second Race Across America, and the nutritionist on my support crew believed that if I followed his megavitamin therapy program, I would win the race. He was in a Ph.D. program and was trained as a nutritionist, so I figured he knew what he was doing. Every six hours I would force down a huge handful of a.s.sorted vitamins and minerals. Their taste and smell nearly made me sick, and they went right through me, producing what I thought had to be the most expensive and colorful urine in America. After three days of this, I decided that megavitamin therapy, along with colonics, iridology, Rofing, and all these other alternative, New Age therapies were a bunch of hooey. On that climb up Loveland Pa.s.s, I dutifully put the vitamins in my mouth and then spit them out up the road when my nutritionist wasn't looking. Being skeptical seemed a lot safer than being credulous.

After the race I discovered that the nutritionist's Ph.D. was to be awarded by a nonaccredited nutrition school and, worse, I was the subject of his doctoral dissertation! Since that time I have noticed about extraordinary claims and New Age beliefs that they tend to attract people on the fringes of academia-people without formal scientific training, creden-tialed (if at all) by nonaccredited schools, lacking research data to support their claims, and excessively boastful about what their particular elixir can accomplish. This does not automatically disprove all claims made by individuals exhibiting these characteristics, but it would be wise to be especially skeptical when encountering them.

Being skeptical is nothing new, of course. Skepticism dates back 2,500 years to ancient Greece and Plato's Academy. But Socrates' quip that "All I know is that I know nothing" doesn't get us far. Modern skepticism has developed into a science-based movement, beginning with Martin Gardner's 1952 cla.s.sic, Fads and Fallacies in the Name of Science. Fads and Fallacies in the Name of Science. Gardner's numerous essays and books over the next four decades, such as Gardner's numerous essays and books over the next four decades, such as Science: Good, Bad, and Bogus Science: Good, Bad, and Bogus (1981), (1981), The New Age: Notes of a Fringe Watcher The New Age: Notes of a Fringe Watcher (1991a), and (1991a), and On the Wild Side On the Wild Side (1992), established a pattern of incredulity about a wide variety of bizarre beliefs. Skepticism joined pop culture through magician James "the Amazing" Randi's countless psychic challenges and media appearances in the 1970s and 1980s (including thirty-six appearances on the (1992), established a pattern of incredulity about a wide variety of bizarre beliefs. Skepticism joined pop culture through magician James "the Amazing" Randi's countless psychic challenges and media appearances in the 1970s and 1980s (including thirty-six appearances on the Tonight Show). Tonight Show). Philosopher Paul Kurtz helped create dozens of skeptics groups throughout the United States and abroad, and publications such as Philosopher Paul Kurtz helped create dozens of skeptics groups throughout the United States and abroad, and publications such as Skeptic Skeptic magazine have national and international circulation. Today, a burgeoning group of people calling themselves skeptics-scientists, engineers, physicians, lawyers, professors, teachers, and the intellectually curious from all walks of life-conduct investigations, hold monthly meetings and annual conferences, and provide the media and the general public with natural explanations for apparently supernatural phenomena. magazine have national and international circulation. Today, a burgeoning group of people calling themselves skeptics-scientists, engineers, physicians, lawyers, professors, teachers, and the intellectually curious from all walks of life-conduct investigations, hold monthly meetings and annual conferences, and provide the media and the general public with natural explanations for apparently supernatural phenomena.

Modern skepticism is embodied in the scientific method, which involves gathering data to test natural explanations for natural phenomena. A claim becomes factual when it is confirmed to such an extent that it would be reasonable to offer temporary agreement. But all facts in science are provisional and subject to challenge, and therefore skepticism is a method method leading to provisional conclusions. Some things, such as water dowsing, extrasensory perception, and creationism, have been tested and have failed the tests often enough that we can provisionally conclude that they are false. Other things, such as hypnosis, lie detectors, and vitamin C, have been tested but the results are inconclusive, so we must continue formulating and testing hypotheses until we can reach a provisional conclusion. The key to skepticism is to navigate the treacherous straits between "know nothing" skepticism and "anything goes" credulity by continuously and vigorously applying the methods of science. leading to provisional conclusions. Some things, such as water dowsing, extrasensory perception, and creationism, have been tested and have failed the tests often enough that we can provisionally conclude that they are false. Other things, such as hypnosis, lie detectors, and vitamin C, have been tested but the results are inconclusive, so we must continue formulating and testing hypotheses until we can reach a provisional conclusion. The key to skepticism is to navigate the treacherous straits between "know nothing" skepticism and "anything goes" credulity by continuously and vigorously applying the methods of science.

The flaw in pure skepticism is that when taken to an extreme, the position itself cannot stand. If you are skeptical about everything, you must be skeptical of your own skepticism. Like the decaying subatomic particle, pure skepticism spins off the viewing screen of our intellectual cloud chamber.

There is also a popular notion that skeptics are closed-minded. Some even call us cynics. In principle, skeptics are not closed-minded or cynical. What I mean by a skeptic is one who questions the validity of a particular claim by calling for evidence to prove or disprove it. one who questions the validity of a particular claim by calling for evidence to prove or disprove it. In other words, skeptics are from Missouri-the "show me" state. When we hear a fantastic claim, we say, "That's nice, prove it." In other words, skeptics are from Missouri-the "show me" state. When we hear a fantastic claim, we say, "That's nice, prove it."

Here is an example. For many years I had heard stories about the "Hundredth Monkey phenomenon" and was fascinated with the possibility that there might be some sort of collective consciousness that we could tap into to decrease crime, eliminate wars, and generally unite as a single species. In the 1992 presidential election, in fact, one candidate-Dr. John Hagelin from the Natural Law Party-claimed that if elected he would implement a plan that would solve the problems of our inner cities: meditation. Hagelin and others (especially proponents of Transcendental Meditation, or TM) believe that thought can somehow be transferred between people, especially people in a meditative state; if enough people meditate at the same time, some sort of critical ma.s.s will be reached, thereby inducing significant planetary change. The Hundredth Monkey phenomenon is commonly cited as empirical proof of this astonishing theory. In the 1950s, so the story goes, j.a.panese scientists gave monkeys on Koshima Island potatoes. One day one of the monkeys learned to wash the potatoes and then taught the skill to others. When about one hundred monkeys had learned the skill-the so-called critical ma.s.s-suddenly all the monkeys knew it, even those on other islands hundreds of miles away. Books about the phenomenon have spread this theory widely in New Age circles. Lyall Watson's Lifetide Lifetide (1979) and Ken Keyes's (1979) and Ken Keyes's The Hundredth Monkey The Hundredth Monkey (1982), for example, have been through multiple printings and sold millions of copies; Elda Hartley even made a film called (1982), for example, have been through multiple printings and sold millions of copies; Elda Hartley even made a film called The Hundredth Monkey. The Hundredth Monkey.

As an exercise in skepticism, start by asking whether events really happened as reported. They did not. In 1952, primatologists began providing j.a.panese macaques with sweet potatoes to keep the monkeys from raiding local farms. One monkey did learn to wash dirt off the sweet potatoes in a stream or the ocean, and other monkeys did learn to imitate the behavior. Now let's examine Watson's book more carefully. He admits that "one has to gather the rest of the story from personal anecdotes and bits of folklore among primate researchers, because most of them are still not quite sure what happened. So I am forced to improvise the details." Watson then speculates that "an unspecified number of monkeys on Koshima were washing sweet potatoes in the sea"-hardly the level of precision one expects. He then makes this statement: "Let us say, for argument's sake, that the number was ninety-nine and that at 11:00 A.M. on a Tuesday, one further convert was added to the fold in the usual way. But the addition of the hundredth monkey apparently carried the number across some sort of threshold, pushing it through a kind of critical ma.s.s." At this point, says Watson, the habit "seems to have jumped natural barriers and to have appeared spontaneously on other islands" (1979, pp. 2-8).

Let's stop right there. Scientists do not "improvise" details or make wild guesses from "anecdotes" and "bits of folklore." In fact, some scientists did did record record exactly exactly what happened (for example, Baldwin et al. 1980; Imanishi 1983; Kawai 1962). The research began with a troop of twenty monkeys in 1952, and every monkey on the island was carefully observed. By 1962, the troop had increased to fifty-nine monkeys and exactly thirty-six of the fifty-nine monkeys were washing their sweet potatoes. The "sudden" acquisition of the behavior actually took ten years, and the "hundred monkeys" were actually only thirty-six in 1962. Furthermore, we can speculate endlessly about what the monkeys knew, but the fact remains that not all of the monkeys in the troop were exhibiting the washing behavior. The thirty-six monkeys were not a critical ma.s.s even at home. And while there are some reports of similar behavior on other islands, the observations were made between 1953 and 1967. It was not sudden, nor was it necessarily connected to Koshima. The monkeys on other islands could have discovered this simple skill themselves, for example, or inhabitants on other islands might have taught them. In any case, not only is there no evidence to support this extraordinary claim, there is not even a real phenomenon to explain. what happened (for example, Baldwin et al. 1980; Imanishi 1983; Kawai 1962). The research began with a troop of twenty monkeys in 1952, and every monkey on the island was carefully observed. By 1962, the troop had increased to fifty-nine monkeys and exactly thirty-six of the fifty-nine monkeys were washing their sweet potatoes. The "sudden" acquisition of the behavior actually took ten years, and the "hundred monkeys" were actually only thirty-six in 1962. Furthermore, we can speculate endlessly about what the monkeys knew, but the fact remains that not all of the monkeys in the troop were exhibiting the washing behavior. The thirty-six monkeys were not a critical ma.s.s even at home. And while there are some reports of similar behavior on other islands, the observations were made between 1953 and 1967. It was not sudden, nor was it necessarily connected to Koshima. The monkeys on other islands could have discovered this simple skill themselves, for example, or inhabitants on other islands might have taught them. In any case, not only is there no evidence to support this extraordinary claim, there is not even a real phenomenon to explain.

Science and Skepticism Skepticism is a vital part of science, which I define as a set of methods designed to describe and interpret observed or inferred phenomena, past or present, and aimed at building a testable body of knowledge open to rejection or confirmation. a set of methods designed to describe and interpret observed or inferred phenomena, past or present, and aimed at building a testable body of knowledge open to rejection or confirmation. In other words, science is a specific way of a.n.a.lyzing information with the goal of testing claims. Defining the In other words, science is a specific way of a.n.a.lyzing information with the goal of testing claims. Defining the scientific method scientific method is not so simple, as philosopher of science and n.o.bel laureate Sir Peter Medawar observed: "Ask a scientist what he conceives the scientific method to be and he will adopt an expression that is at once solemn and shifty-eyed: solemn, because he feels he ought to declare an opinion; shifty-eyed, because he is wondering how to conceal the fact that he has no opinion to declare" (1969, p. 11). is not so simple, as philosopher of science and n.o.bel laureate Sir Peter Medawar observed: "Ask a scientist what he conceives the scientific method to be and he will adopt an expression that is at once solemn and shifty-eyed: solemn, because he feels he ought to declare an opinion; shifty-eyed, because he is wondering how to conceal the fact that he has no opinion to declare" (1969, p. 11).

A sizable literature exists on the scientific method, but there is little consensus among authors. This does not mean that scientists do not know what they are doing. Doing and explaining may be two different things. However, scientists agree that the following elements are involved in thinking scientifically: Induction: Forming a hypothesis by drawing general conclusions from existing data. Forming a hypothesis by drawing general conclusions from existing data.

Deduction: Making specific predictions based on the hypotheses. Making specific predictions based on the hypotheses.

Observation: Gathering data, driven by hypotheses that tell us what to look for in nature. Gathering data, driven by hypotheses that tell us what to look for in nature.

Verification: Testing the predictions against further observations to confirm or falsify the initial hypotheses. Testing the predictions against further observations to confirm or falsify the initial hypotheses.

Science, of course, is not this rigid; and no scientist consciously goes through "steps." The process is a constant interaction of making observations, drawing conclusions, making predictions, and checking them against evidence. And data-gathering observations are not made in a vacuum. The hypotheses shape what sorts of observations you will make of nature, and these hypotheses are themselves shaped by your education, culture, and particular biases as an observer.

This process const.i.tutes the core of what philosophers of science call the hypothetico-deductive hypothetico-deductive method, which, according to the method, which, according to the Dictionary of the History of Science, Dictionary of the History of Science, involves "(a) putting forward a hypothesis, (b) conjoining it with a statement of 'initial conditions,' (c) deducing from the two a prediction, and (d) finding whether or not the prediction is fulfilled" (Bynum, Browne, and Porter 1981, p. 196). It is not possible to say which came first, the observation or the hypothesis, since the two are inseparably interactive. But additional observations are what flesh out the hypothetico-deductive process, and they serve as the final arbiter on the validity of predictions. As Sir Arthur Stanley Eddington noted, "For the truth of the conclusions of science, observation is the supreme court of appeal" (1958, p. 9). Through the scientific method, we may form the following generalizations: involves "(a) putting forward a hypothesis, (b) conjoining it with a statement of 'initial conditions,' (c) deducing from the two a prediction, and (d) finding whether or not the prediction is fulfilled" (Bynum, Browne, and Porter 1981, p. 196). It is not possible to say which came first, the observation or the hypothesis, since the two are inseparably interactive. But additional observations are what flesh out the hypothetico-deductive process, and they serve as the final arbiter on the validity of predictions. As Sir Arthur Stanley Eddington noted, "For the truth of the conclusions of science, observation is the supreme court of appeal" (1958, p. 9). Through the scientific method, we may form the following generalizations: Hypothesis: A testable statement accounting for a set of observations. A testable statement accounting for a set of observations.

Theory: A well-supported and well-tested hypothesis or set of hypotheses. A well-supported and well-tested hypothesis or set of hypotheses.

Fact: A conclusion confirmed to such an extent that it would be reasonable to offer provisional agreement. A conclusion confirmed to such an extent that it would be reasonable to offer provisional agreement.

A theory may be contrasted with a construct: construct: a nontestable statement to account for a set of observations.The living organisms on Earth may be accounted for by the statement "G.o.d made them" or the statement "They evolved." The first statement is a construct, the second a theory. Most biologists would even call evolution a fact. a nontestable statement to account for a set of observations.The living organisms on Earth may be accounted for by the statement "G.o.d made them" or the statement "They evolved." The first statement is a construct, the second a theory. Most biologists would even call evolution a fact.

Through the scientific method, we aim for objectivity: objectivity: basing conclusions on external validation. And we avoid basing conclusions on external validation. And we avoid mysticism: mysticism: basing conclusions on personal insights that elude external validation. basing conclusions on personal insights that elude external validation.

There is nothing wrong with personal insight as a starting point. Many great scientists have attributed their important ideas to insight, intuition, and other mental leaps hard to pin down. Alfred Russel Wallace said that the idea of natural selection "suddenly flashed upon" him during an attack of malaria. But intuitive ideas and mystical insights do not become objective until they are externally validated. As psychologist Richard Hardison explained, Mystical "truths," by their nature, must be solely personal, and they can have no possible external validation. Each has equal claim to truth. Tealeaf reading and astrology and Buddhism; each is equally sound or unsound if we judge by the absence of related evidence. This is not intended to disparage any one of the faiths; merely to note the impossibility of verifying their correctness. The mystic is in a paradoxical position. When he seeks external support for his views he must turn to external arguments, and he denies mysticism in the process. External validation is, by definition, impossible for the mystic. (1988, pp. 259-260) Science leads us toward rationalism: rationalism: basing conclusions on logic and evidence. For example, how do we know the Earth is round? It is a logical conclusion drawn from observations such as basing conclusions on logic and evidence. For example, how do we know the Earth is round? It is a logical conclusion drawn from observations such as *The shadow of the Earth on the moon is round.

*The mast of a ship is the last thing seen as it sails into the distance.

*The horizon is curved.

*Photographs from s.p.a.ce.

And science helps us avoid dogmatism: dogmatism: basing conclusions on authority rather than logic and evidence. For example, how do we know the Earth is round? basing conclusions on authority rather than logic and evidence. For example, how do we know the Earth is round?

*Our parents told us.

*Our teachers told us.

*Our minister told us.

*Our textbook told us.

Dogmatic conclusions are not necessarily invalid, but they do beg other questions: How did the authorities come by their conclusions? Were they guided by science or some other means?

The Essential Tension Between Skepticism and Credulity It is important to recognize the fallibility of science and the scientific method. But within this fallibility lies its greatest strength: self-correction. Whether a mistake is made honestly or dishonestly, whether a fraud is unknowingly or knowingly perpetrated, in time it will be flushed out of the system by lack of external verification. The cold fusion fiasco is a cla.s.sic example of the system's swift exposure of error.

Because of the importance of this self-correcting feature, among scientists there is at best what Caltech physicist and n.o.bel laureate Richard Feynman called "a principle of scientific thought that corresponds to a kind of utter honesty-a kind of leaning over backwards." Said Feynman, "If you're doing an experiment, you should report everything that you think might make it invalid-not only what you think is right about it: other causes that could possibly explain your results" (1988, p. 247).

Despite these built-in mechanisms, science remains subject to problems and fallacies ranging from inadequate mathematical notation to wishful thinking. But, as philosopher of science Thomas Kuhn (1977) noted, the "essential tension" in science is between total commitment to the status quo and blind pursuit of new ideas. The paradigm shifts and revolutions in science depend upon proper balancing of these opposing impulses. When enough of the scientific community (particularly those in positions of power) are willing to abandon orthodoxy in favor of the (formerly) radical new theory, then and only then can a paradigm shift occur (see chapter 2).

Charles Darwin is a good example of a scientist who negotiated the essential tension between skepticism and credulity. Historian of science Frank Sulloway identifies three characteristics in Darwin's thinking that helped Darwin find his balance: (1) he respected others' opinions but was willing to challenge authorities (he intimately understood the theory of special creation, yet he overturned it with his own theory of natural selection); (2) he paid close attention to negative evidence (Darwin included a chapter called "Difficulties on Theory" in the Origin of Species Origin of Species-as a result his opponents could rarely present him with a challenge that he had not already addressed); (3) he generously used the work of others (Darwin's collected correspondence numbers over 14,000 letters, most of which include lengthy discussions and question-and-answer sequences about scientific problems). Darwin was constantly questioning, always learning, confident enough to formulate original ideas yet modest enough to recognize his own fallibility. "Usually, it is the scientific community as a whole that displays this essential tension between tradition and change," Sulloway observed, "since most people have a preference for one or the other way of thinking. What is relatively rare in the history of science is to find these contradictory qualities combined in such a successful manner in one individual" (1991, p. 32).

The essential tension in dealing with "weird things" is between being so skeptical that revolutionary ideas pa.s.s you by and being so open-minded that flimflam artists take you in. Balance can be found by answering a few basic questions: What is the quality of the evidence for the claim? What are the background and credentials of the person making the claim? Does the thing work as claimed? As I discovered during my personal odyssey in the world of alternative health and fitness therapies and gadgets, often the evidence is weak, the background and credentials of the claimants are questionable, and the therapy or gadget almost never does what it is supposed to.

This last point may well be the crucial one. I regularly receive calls about astrology. Callers usually want to know about the theory behind astrology. They are wondering whether the alignment of planetary bodies can significantly influence human destiny. The answer is no, but the more important point is that one need not understand gravity and the laws governing the motion of the p