How to Be A Skeptic

By Michael Shermer

From Why People Believe Weird Things: Pseudoscience, Superstition, and Other Confusions of Our Time.
( 1997 by Michael Shermer. Used with permission of W H. Freeman and Company.

Most of us, most of the time, want certainty, need to control our environment, and would like nice, neat, simple explanations. The pressures of reality lead us to be fascinated by mysteries, to seek spiritual meaning in our lives, and to hope for immorta lity. These desires may have some evolutionary basis, but they can interfere with critical thinking and problem solving. As a result, we may be seduced by the promises and claims of astrologers, psychics, and other pseudoscientists who deal in flimsy ev idence and faulty logic. Here are some warning signs to watch out for before suspending disbelief.

Bold Statements Do Not Make True Claims:
A red flag that something is pseudoscientific is when enormous claims are made for its power and veracity, especially when supportive evidence is lacking. At the offices of Skeptic magazine, I have a file filled with papers and letters with outlandish cl aims from obscure authors (I call it the "theories of everything" file). Scientists sometimes make this mistake, and when they are wrong they pay a high price. We saw this when Stanley Pons and Martin Fleischmann announced to the world, through a press conference, that they had discovered cold nuclear fusion.

Heresy Does Not Equal Correctness:
They laughed at Copernicus. They laughed at the Wright Brothers. Yes, well, they also laughed at the Marx Brothers. Being laughed at does not mean you are right. Reprinted in an issue of the Journal of Historical Review, the voice of Holocaust denial, is a famous quote from the nineteenth-century philosopher Arthur Schopenhauer: "All truth passes through three stages. First, it is ridiculed. Second, it is violently opposed. Third, it is accepted as self-evident." This is just a rationalization by th ose who are rejected to say, "See, I must be right." Not necessarily. Besides, lots of new ideas, such as Einstein's theory of relativity, are accepted without ridicule or violence.

After the Fact Reasoning and Coincidence:
As the eighteenth-century Scottish philosopher David Hume taught correedy, just because two events follow each other in sequence does not mean they are connected causally. That kind of reasoning, known as post hoc, ergo propter hoc (after this, therefor e because of this), is, at its basest level, a form of superstition. Similarly, coincidences are often seen as deeply significant. You go to the phone to call your friend Bob. The phone rings, and it is Bob. You think, "Wow, what are the chances that this is a mere coincidence? Maybe Bob and I are communicating telepathically." But most people actually have a very poor understanding of the laws of chance or probability.

Lack of an Appropriate Frame of Reference or Control:
Seemingly unusual events must be considered against the proper background for that class of phenomena. In the case of the Bermuda Triangle, where ships and planes are said to mysteriously disappear, something strange or alien is often assumed to be at w ork. But far more ships crisscross the Bermuda Triangle than surrounding areas, so accidents and mishaps are more likely to happen there. As it turns out, there are actually fewer accidents in the Bermuda Triangle, per rate of traffic, than in surroundi ng areas. Similarly, anecdotes about miracle cures for cancer are not meaningful; we need controlled studies.

Failures Are Rationalized:
In science the value of negative findings-failures-cannot be overemphasized. Usually they are not wanted and often they are not published. But most of the time, failures are how we get closer to the truth. Pseudoscientists' failures are rationalized-a psychic may say his or her powers do not work in the presence of skeptics or electrical equipment. Or failures are ignored-we tend to forget the predictions that don't come true and only remember the unusual occurrences.

Either-Or:
Also known as the fallacy of negation or false dilemma, this is the tendency to dichotomize the world so that when you discredit one possibility, the observer is forced to accept the other. This is a favorite tactic of the creationists, who spend the ma jority of their time trying to discredit the theory of evolution, concluding that since evolution is wrong, creationism must be right. Similarly, some argue that if you cannot disprove a claim, it must be true. For example, if you cannot prove there is not psychic power, then there must be. But it is not enough to point out weaknesses in a theory. If yours is indeed superior, it must explain both the "normal" data and the "anomalous" data not explained by the old theory. It needs evidence in favor of it, not just against the opposition.

Burden of Proof:
The person making the extraordinary claim has the burden of proving to the experts and to the cormmunity that his or her belief has more validity than the one generally accepted. Evolutionists had the burden of proof for half a century after Darwin and now enjoy the reverse role. Similarly, the burden of proof is on the Holocaust deniers to prove the Holocaust did not happen, not on Holocaust historians to prove that it did. The reason is that mountains of evidence prove that both evolution and the Ho locaust are facts of history.

These are just some of the considerations that make me a skeptic. Perhaps the best advice to follow, in the face of an unusual claim, was given by Hume, in An Enquiry Concerning Human Understanding:

When anyone tells me that he saw a dead man restored to life, I immediately consider with myself whether it be more probable, that this person should either deceive or be deceived, or that the fact, which he relates, should really have happene d.... If the falsehood of his testimony would be more miraculous than the event which he relates, then, and not till then, can he pretend to command my belief or opinion.

Michael Shermer, who teaches at Occidental College in Los Angeles, is the director of the Skeptics Society.


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larry-zimmerman@uiowa.edu
University of Iowa Anthropology

08/18/98