By Michael Shermer

When lecturing on science and pseudoscience at colleges and universities, I am inevitably asked, after

challenging common beliefs held by many students, "Why should we believe you?" My answer: "You

shouldn't."

I then explain that we need to check things out for ourselves and, short of that, at least to ask basic

questions that get to the heart of the validity of any claim. This is what I call baloney detection, in

deference to Carl Sagan, who coined the phrase "Baloney Detection Kit." To detect baloney--that is, to

help discriminate between science and pseudoscience--I suggest 10 questions to ask when

encountering any claim.

Pseudoscientists often appear quite reliable, but when examined closely, the facts and figures they cite

are distorted, taken out of context or occasionally even fabricated. Of course, everyone makes some

mistakes. And as historian of science Daniel Kevles showed so effectively in his book The Baltimore

Affair, it can be hard to detect a fraudulent signal within the background noise of sloppiness that is a

normal part of the scientific process. The question is, Do the data and interpretations show signs of

intentional distortion? When an independent committee established to investigate potential fraud

scrutinized a set of research notes in Nobel laureate David Baltimore's laboratory, it revealed a

surprising number of mistakes. Baltimore was exonerated because his lab's mistakes were random and

nondirectional.

Pseudoscientists have a habit of going well beyond the facts. Flood geologists (creationists who believe

that Noah's flood can account for many of the earth's geologic formations) consistently make

outrageous claims that bear no relation to geological science. Of course, some great thinkers do

frequently go beyond the data in their creative speculations. Thomas Gold of Cornell University is

notorious for his radical ideas, but he has been right often enough that other scientists listen to what

he has to say. Gold proposes, for example, that oil is not a fossil fuel at all but the by-product of a

deep, hot biosphere (microorganisms living at unexpected depths within the crust). Hardly any earth

scientists with whom I have spoken think Gold is right, yet they do not consider him a crank. Watch

out for a pattern of fringe thinking that consistently ignores or distorts data.

Typically pseudoscientists make statements that are unverified or verified only by a source within their

own belief circle. We must ask, Who is checking the claims, and even who is checking the checkers?

The biggest problem with the cold fusion debacle, for instance, was not that Stanley Pons and Martin

Fleischman were wrong. It was that they announced their spectacular discovery at a press conference

before other laboratories verified it. Worse, when cold fusion was not replicated, they continued to

cling to their claim. Outside verification is crucial to good science.

An extraordinary claim must be placed into a larger context to see how it fits. When people claim that

the Egyptian pyramids and the Sphinx were built more than 10,000 years ago by an unknown,

advanced race, they are not presenting any context for that earlier civilization. Where are the rest of

the artifacts of those people? Where are their works of art, their weapons, their clothing, their tools,

their trash? Archaeology simply does not operate this way.

This is the confirmation bias, or the tendency to seek confirmatory evidence and to reject or ignore

disconfirmatory evidence. The confirmation bias is powerful, pervasive and almost impossible for any

of us to avoid. It is why the methods of science that emphasize checking and rechecking, verification

and replication, and especially attempts to falsify a claim, are so critical.

The theory of evolution, for example, is proved through a convergence of evidence from a number of

independent lines of inquiry. No one fossil, no one piece of biological or paleontological evidence has

"evolution" written on it; instead tens of thousands of evidentiary bits add up to a story of the

evolution of life. Creationists conveniently ignore this confluence, focusing instead on trivial anomalies

or currently unexplained phenomena in the history of life.

A clear distinction can be made between SETI (Search for Extraterrestrial Intelligence) scientists and

UFOlogists. SETI scientists begin with the null hypothesis that ETIs do not exist and that they must

provide concrete evidence before making the extraordinary claim that we are not alone in the

universe. UFOlogists begin with the positive hypothesis that ETIs exist and have visited us, then

employ questionable research techniques to support that belief, such as hypnotic regression

(revelations of abduction experiences), anecdotal reasoning (countless stories of UFO sightings),

conspiratorial thinking (governmental cover-ups of alien encounters), low-quality visual evidence

(blurry photographs and grainy videos), and anomalistic thinking (atmospheric anomalies and visual

misperceptions by eyewitnesses).

This is a classic debate strategy--criticize your opponent and never affirm what you believe to avoid

criticism. It is next to impossible to get creationists to offer an explanation for life (other than "God did

it"). Intelligent Design (ID) creationists have done no better, picking away at weaknesses in scientific

explanations for difficult problems and offering in their stead "ID did it." This stratagem is

unacceptable in science.

Many HIV/AIDS skeptics argue that lifestyle causes AIDS. Yet their alternative theory does not explain

nearly as much of the data as the HIV theory does. To make their argument, they must ignore the

diverse evidence in support of HIV as the causal vector in AIDS while ignoring the significant

correlation between the rise in AIDS among hemophiliacs shortly after HIV was inadvertently

introduced into the blood supply.

All scientists hold social, political and ideological beliefs that could potentially slant their interpretations

of the data, but how do those biases and beliefs affect their research in practice? Usually during the

peer-review system, such biases and beliefs are rooted out, or the paper or book is rejected.

Clearly, there are no foolproof methods of detecting baloney or drawing the boundary between science

and pseudoscience. Yet there is a solution: science deals in fuzzy fractions of certainties and

uncertainties, where evolution and big bang cosmology may be assigned a 0.9 probability of being

true, and creationism and UFOs a 0.1 probability of being true. In between are borderland claims: we

might assign superstring theory a 0.7 and cryonics a 0.2. In all cases, we remain open-minded and

flexible, willing to reconsider our assessments as new evidence arises. This is, undeniably, what makes

science so fleeting and frustrating to many people; it is, at the same time, what makes science the

most glorious product of the human mind.