[Editorial note: This is taken from the book The Demon-Haunted World: Science as a Candle in the Dark.]

The Fine Art of Baloney Detection

by Carl Sagan

My parents died years ago. I was very close to them. I still miss them terribly. I know I always will. I long to believe that their essence, their personalities, what I loved so much about them, are — really and truly — still in existence somewhere. I wouldn't ask very much, just five or ten minutes a year, say, to tell them about their grandchildren, to catch them up on the latest news, to remind them that I love them. There's a part of me — no matter how childish it sounds — that wonders how they are. "Is everything all right?" I want to ask. The last words I found myself saying to my father, at the moment of his death, were "Take care."

Sometimes I dream that I'm talking to my parents, and suddenly — still immersed in the dreamwork — I'm seized by the overpowering realization that they didn't really die, that it's all been some kind of horrible mistake. Why, here they are, alive and well, my father making wry jokes, my mother earnestly advising me to wear a muffler because the weather is chilly. When I wake up I go through an abbreviated process of mourning all over again. Plainly, there's something within me that's ready to believe in life after death. And it's not the least bit interested in whether there's any sober evidence for it.

So I don't guffaw at the woman who visits her husband's grave and chats him up every now and then, maybe on the anniversary of his death. It's not hard to understand. And if I have difficulties with the ontological status of who she's talking to, that's all right. That's not what this is about. This is about humans being human. More than a third of American adults believe that on some level they've made contact with the dead. The number seems to have jumped by 15 percent between 1977 and 1988. A quarter of Americans believe in reincarnation.

But that doesn't mean I'd be willing to accept the pretensions of a "medium," who claims to channel the spirits of the dear departed, when I'm aware the practice is rife with fraud. I know how much I want to believe that my parents have just abandoned the husks of their bodies, like insects or snakes molting, and gone somewhere else. I understand that those very feelings might make me easy prey even for an unclever con, or for normal people unfamiliar with their unconscious minds, or for those suffering from a dissociative psychiatric disorder. Reluctantly, I rouse some reserves of skepticism.

How is it, I ask myself, that channelers never give us verifiable information otherwise unavailable? Why does Alexander the Great never tell us about the exact location of his tomb, Fermat about his Last Theorem, John Wilkes Booth about the Lincoln assassination conspiracy, Hermann Goring about the Reichstag fire? Why don't Sophocles, Democritus, and Aristarchus dictate their lost books? Don't they wish future generations to have access to their masterpieces?

If some good evidence for life after death were announced, I'd be eager to examine it; but it would have to be real scientific data, not mere anecdote. As with the face on Mars and alien abductions, better the hard truth, I say, than the comforting fantasy. And in the final tolling it often turns out that the facts are more comforting than the fantasy.

The fundamental premise of "channeling," spiritualism, and other forms of necromancy is that when we die we don't. Not exactly. Some thinking, feeling, and remembering part of us continues. That whatever-it-is — a soul or spirit, neither matter nor energy, but something else — can, we are told, re-enter the bodies of human and other beings in the future, and so death loses much of its sting. What's more, we have an opportunity, if the spiritualist or channeling contentions are true, to make contact with loved ones who have died.

J.Z. Knight of the State of Washington claims to be in touch with a 35,000-year-old somebody called "Ramtha." He speaks English very well, using Knight's tongue, lips and vocal chords, producing what sounds to me to be an accent from the Indian Raj. Since most people know how to talk, and many — from children to professional actors — have a repertoire of voices at their command, the simplest hypothesis is that Ms. Knight makes "Ramtha" speak all by herself, and that she has no contact with disembodied entities from the Pleistocene Ice Age. If there's evidence to the contrary, I'd love to hear it. It would be considerably more impressive if Ramtha could speak by himself, without the assistance of Ms. Knight's mouth. Failing that, how might we test the claim? (The actress Shirley MacLaine attests that Ramtha was her brother in Atlantis, but that's another story.)

Suppose Ramtha were available for questioning. Could we verify whether he is who he says he is? How does he know that he lived 35,000 years ago, even approximately? What calendar does he employ? Who is keeping track of the intervening millennia? Thirty-five thousand plus or minus what? What were things like 35,000 years ago? Either Ramtha really is 35,000 years old, in which case we discover something about that period, or he's a phony and he'll (or rather she'll) slip up.

Where did Ramtha live? (I know he speaks English with an Indian accent, but where 35,000 years ago did they do that?) What was the climate? What did Ramtha eat? (Archaeologists know something about what people ate back then.) What were the indigenous languages, and social structure? Who else did Ramtha live with — wife, wives, children, grandchildren? What was the life cycle, the infant mortality rate, the life expectancy? Did they have birth control? What clothes did they wear? How were the clothes manufactured? What were the most dangerous predators? Hunting and fishing implements and strategies? Weapons? Endemic sexism? Xenophobia and ethnocentrism? And if Ramtha came from the "high civilization" of Atlantis, where are the linguistic, technological, historical and other details? What was their writing like? Tell us. Instead, all we are offered are banal homilies.

Here, to take another example, is a set of information channeled not from an ancient dead person, but from unknown non-human entities who make crop circles, as recorded by the journalist Jim Schnabel:

We are so anxious at this sinful nation spreading lies about us. We do not come in machines, we do not land on your earth in machines ... We come like the wind. We are Life Force. Life Force from the ground ... Come here ... We are but a breath away ... a breath away ... we are not a million miles away ... a Life Force that is larger than the energies in your body. But we meet at a higher level of life ... We need no name. We are parallel to your world, alongside your world ... The walls are broken. Two men will rise from the past ... the great bear ... the world will be at peace.

People pay attention to these puerile marvels mainly because they promise something like old-time religion, but especially life after death, even life eternal.

A very different prospect for something like eternal life was once proposed by the versatile British scientist J.B.S. Haldane, who was, among many other things, one of the founders of population genetics. Haldane imagined a far future when the stars have darkened and space is mainly filled with a cold, thin gas. Nevertheless, if we wait long enough statistical fluctuations in the density of this gas will occur. Over immense periods of time the fluctuations will be sufficient to reconstitute a Universe something like our own. If the Universe is infinitely old, there will be an infinite number of such reconstitutions, Haldane pointed out.

So in an infinitely old universe with an infinite number of appearances of galaxies, stars, planets, and life, an identical Earth must reappear on which you and all your loved ones will be reunited. I'll be able to see my parents again and introduce them to the grandchildren they never knew. And all this will happen not once, but an infinite number of times.

Somehow, though, this does not quite offer the consolations of religion. If none of us is to have any recollection of what happened this time around, the time the reader and I are sharing, the satisfactions of bodily resurrection, in my ears at least, ring hollow.

But in this reflection I have underestimated what infinity means. In Haldane's picture, there will be universes, indeed an infinite number of them, in which our brains will have full recollection of many previous rounds. Satisfaction is at hand — tempered, though, by the thought of all those other universes which will also come into existence (again, not once but an infinite number of times) with tragedies and horrors vastly outstripping anything I've experienced this turn.

The Consolation of Haldane depends, though, on what kind of universe we live in, and maybe on such arcana as whether there's enough matter to eventually reverse the expansion of the universe, and the character of vacuum fluctuations. Those with a deep longing for life after death might, it seems, devote themselves to cosmology, quantum gravity, elementary particle physics, and transfinite arithmetic.

Clement of Alexandria, a Father of the early Church, in his Exhortations to the Greeks (written around the year 190) dismissed pagan beliefs in words that might today seem a little ironic:

Far indeed are we from allowing grown men to listen to such tales. Even to our own children, when they are crying their heart out, as the saying goes, we are not in the habit of telling fabulous stories to soothe them.

In our time we have less severe standards. We tell children about Santa Claus, the Easter Bunny, and the Tooth Fairy for reasons we think emotionally sound, but then disabuse them of these myths before they're grown. Why retract? Because their well-being as adults depends on them knowing the world as it really is. We worry, and for good reason, about adults who still believe in Santa Claus.

On doctrinaire religions, "Men dare not avow, even to their own hearts," wrote the philosopher David Hume,

the doubts which they entertain on such subjects. They make a merit of implicit faith; and disguise to themselves their real infidelity, by the strongest asseverations and the most positive bigotry.

This infidelity has profound moral consequences, as the American revolutionary Tom Paine wrote in The Age of Reason:

Infidelity does not consist in believing, or in disbelieving; it consists in professing to believe what one does not believe. It is impossible to calculate the moral mischief, if I may so express it, that mental lying has produced in society. When man has so far corrupted and prostituted the chastity of his mind, as to subscribe his professional belief to things he does not believe, he has prepared himself for the commission of every other crime.

T. H. Huxley's formulation was

The foundation of morality is to ... give up pretending to believe that for which there is no evidence, and repeating unintelligible propositions about things beyond the possibilities of knowledge.

Clement, Hume, Paine, and Huxley were all talking about religion. But much of what they wrote has more general applications — for example to the pervasive background importunings of our commercial civilization: There is a class of aspirin commercials in which actors pretending to be doctors reveal the competing product to have only so much of the painkilling ingredient that doctors recommend most — they don't tell you what the mysterious ingredient is. Whereas their product has a dramatically larger amount (1.2 to 2 times more per tablet). So buy their product. But why not just take two of the competing tablets? Or consider the analgesic that works better than the "regular-strength" product of the competition. Why not then take the "extra-strength" competitive product? And of course they do not tell us of the more than a thousand deaths each year in the United States from the use of aspirin, or the roughly 5000 annual cases of kidney failure from the use of acetaminophen, chiefly Tylenol. Or who cares which breakfast cereal has more vitamins when we can take a vitamin pill with breakfast? Likewise, why should it matter whether an antacid contains calcium if the calcium is for nutrition and irrelevant for gastritis? Commercial culture is full of similar misdirections and evasions at the expense of the consumer. You're not supposed to ask. Don't think. Buy.

Paid product endorsements, especially by real or purported experts, constitute a steady rainfall of deception. They betray contempt for the intelligence of their customers. They introduce an insidious corruption of popular attitudes about scientific objectivity. Today there are even commercials in which real scientists, some of considerable distinction, shill for corporations. They teach that scientists too will lie for money. As Tom Paine warned, inuring us to lies lays the groundwork for many other evils.

I have in front of me as I write the program of one of the annual Whole Life Expos, New Age expositions held in San Francisco. Typically, tens of thousands of people attend. Highly questionable experts tout highly questionable products. Here are some of the presentations: "How Trapped Blood Proteins Produce Pain and Suffering." "Crystals, Are They Talismans or Stones?" (I have an opinion myself.) It continues: "As a crystal focuses sound and light waves for radio and television" — this is a vapid misunderstanding of how radio and television work — "so may it amplify spiritual vibrations for the attuned human." Or here's one "Return of the Goddess, a Presentational Ritual." Another: "Synchronicity, the Recognition Experience." That one is given by "Brother Charles." Or, on the next page, "You, Saint-Germain, and Healing Through the Violet Flame." It goes on and on, with plenty of ads about "opportunities" — running the short gamut from the dubious to the spurious — that are available at the Whole Life Expo.

Distraught cancer victims make pilgrimages to the Philippines, where "psychic surgeons," having palmed bits of chicken liver or goat heart, pretend to reach into the patient's innards and withdraw the diseased tissue, which is then triumphantly displayed. Leaders of Western democracies regularly consult astrologers and mystics before making decisions of state. Under public pressure for results, police with an unsolved murder or a missing body on their hands consult ESP "experts" (who never guess better than expected by common sense, but the police, the ESPers say, keep calling). A clairvoyance gap with adversary nations is announced, and the Central Intelligence Agency, under Congressional prodding, spends tax money to find out whether submarines in the ocean depths can be located by thinking hard at them. A "psychic" — using pendulums over maps and dowsing rods in airplanes — purports to find new mineral deposits; an Australian mining company pays him top dollar up front, none of it returnable in the event of failure, and a share in the exploitation of ores in the event of success. Nothing is discovered. Statues of Jesus or murals of Mary are spotted with moisture, and thousands of kind-hearted people convince themselves that they have witnessed a miracle.

These are all cases of proved or presumptive baloney. A deception arises, sometimes innocently but collaboratively, sometimes with cynical premeditation. Usually the victim is caught up in a powerful emotion — wonder, fear, greed, grief. Credulous acceptance of baloney can cost you money; that's what P. T. Barnum meant when he said, "There's a sucker born every minute." But it can be much more dangerous than that, and when governments and societies lose the capacity for critical thinking, the results can be catastrophic — however sympathetic we may be to those who have bought the baloney.

In science we may start with experimental results, data, observations, measurements, "facts." We invent, if we can, a rich array of possible explanations and systematically confront each explanation with the facts. In the course of their training, scientists are equipped with a baloney detection kit. The kit is brought out as a matter of course whenever new ideas are offered for consideration. If the new idea survives examination by the tools in our kit, we grant it warm, although tentative, acceptance. If you're so inclined, if you don't want to buy baloney even when it's reassuring to do so, there are precautions that can be taken; there's a tried-and-true, consumer-tested method.

What's in the kit? Tools for skeptical thinking.

What skeptical thinking boils down to is the means to construct, and to understand, a reasoned argument and — especially important — to recognize a fallacious or fraudulent argument. The question is not whether we like the conclusion that emerges out of a train of reasoning, but whether the conclusion follows from the premise or starting point and whether that premise is true.

Among the tools:

In addition to teaching us what to do when evaluating a claim to knowledge, any good baloney detection kit must also teach us what not to do. It helps us recognize the most common and perilous fallacies of logic and rhetoric. Many good examples can be found in religion and politics, because their practitioners are so often obliged to justify two contradictory propositions. Among these fallacies are:

Knowing the existence of such logical and rhetorical fallacies rounds out our toolkit. Like all tools, the baloney detection kit can be misused, applied out of context, or even employed as a rote alternative to thinking. But applied judiciously, it can make all the difference in the world — not least in evaluating our own arguments before we present them to others.