Skeptical Inquiry

1. What is Skeptical Inquiry?

Skeptical inquiry is a method of investigation which guides the evaluation of claims of fact. Four words neatly summarize the skeptical credo: Prove what you claim!

Skepticism's core value judgment holds that empirical evidence must support a falsifiable claim to justify acceptance of that claim. A skeptic strives to identify and clearly articulate assumptions and, when they are questioned, rigorously test those assumptions. Science is the best tool yet-invented for producing evidence that skeptics consider valid.

2. Bases of Evidence

Skeptical inquiry borrows its core bases of evidence, empiricism and falsifiability, from science. A falsifiable claim is stated in a way such that it can be proved false. Examples of falsifiable claims are "It is raining outside" or "The sun will rise tomorrow." On the other hand, "Chocolate is better than vanilla" is not falsifiable.

In this essay, the word empirical is used in senses one and three of Merriam-Webster's definition:

  1. originating in or based on observation or experience <empirical data>
  2. capable of being verified or disproved by observation or experiment <empirical laws>

3. Biology & Medicine

Biomedical science provides rich fodder for skeptical inquiry, from outright nonsense to quackery (e.g., touch therapy), to placebo therapies (homeopathy, acupuncture), to borderline practices (chiropractic). While these examples are not generally considered medically harmful, they are excellent tools for fleecing people unfamiliar with the basic tenets of science and medicine. Hucksters make their money with wild claims of medical benefits for bogus (or at best, untested) therapies. Patients with debilitating or life-threatening conditions are among the most vulnerable members of our society, and we have a moral duty to expose those who would separate them from their money through dishonest practices.

The recent public and regulatory spate over ephedra highlights the need for skeptical inquiry in everyday life. The Dietary Supplement and Health Education Act of 1994 exempted "natural" and substances from the rules that require ordinary pharmaceuticals to be proven safe and effective before they may be marketed. (We should always be skeptical of lawmakers' motives when they are financially interested in companies that will benefit direction from the legislation they sponsor.) For over three years after ephedra-based products were introduced as over-the-counter diet supplements, scientists could not state with certainty whether ephedra was a "dangerous" or a "safe" substance. By the time Orioles pitcher Steve Bechler died from heart-related problems (a long-suspected ephedra side effect) after taking ephedra in February 2003, over 100 deaths were suspected of being linked to the substance. Politicians began tripping over one another, each trying to appear the most concerned about it. Bans were proposed to the Food & Drug Administration (FDA), private organizations (such as sports leagues) barred their members from using it, companies producing it saw their reputations harmed, and the public was simply confused. Patient, scientific investigation of ephedra's properties and its effects on the human body might have prevented much of this confusion.

As 2003 drew to a close, the FDA finally banned ephedra, citing safety concerns. This will remove some of the time pressure to resolve the scientific questions surrounding the substance. People will stop dying, but we still face the lesser concern of economic harm to the producers of ephedra-based products, so the time pressure is not completely alleviated. Still, I will gladly accept these economic harms over people's deaths when the evidence is so mixed.


Medicine is by no means the only field for practical skeptical inquiry. Skeptics address such questions as small as whether coyotes are present in Nashville, Tennessee and as large as whether life exists on other planets. Politically sensitive topics are not immune from skeptical inquiry, although skeptics usually avoid inflammatory investigations unless they have a good reason. The viability of the National Missile Defense system is one example where the reason (billions of wasted dollars) is sufficiently compelling. The more fun and frivolous claims of fact involve the paranormal, from cryptozoology to UFOs to spoon bending. A skeptic's work is never done.

Skeptics generally refrain from inquiring into religious beliefs for two reasons. First, true religious beliefs are ones that rely purely on faith. They are, by definition, stated in a nonfalsifiable manner; so skeptical inquiry could, by definition, never provide satisfying answers to religious questions. Second, religion is one of the most private and sensitive aspects of one's persona — so affected with one's identity that many people confuse it with their identity. Invading that sphere would be disrespectful and crass. However, religious people occasionally make empirical claims of fact about their religions, and these are fair game for investigation. Two recent examples illustrate how claims that arise from religion can morph into empirical claims.

Example #1: In October 2002, archaeologist Andrι Lemaire announced his discovery of an ossuary bearing the inscription, "James, son of Joseph, brother of Jesus." His article in Biblical Archaeology Review fueled a worldwide brouhaha and inspired many Christians to publicly reaffirm their belief in the biblical story of Jesus. Whether Jesus really existed and, if so, whether he was the son of a deity are "facts" which cannot be proved or disproved with tangible evidence and therefore lie outside the realm of skeptical inquiry. The authenticity of the ossuary and its inscription, however, is an example of a classic falsifiable claim. After the bone box's owner permitted other experts to examine it, it was resoundingly declared a fake by most of those who examined it.

Example #2: In October 2003, the Catholic church announced a "clinical" finding that condoms are responsible for the fast spread of AIDS throughout the world. Cardinal Alfonso Lopez Trujillo, president of the Vatican 's Pontifical Council for the Family, explains that condoms are not 100% effective at blocking sperm and that the HIV virus is 450 smaller than sperm. HIV can permeate the condom's barrier more easily than sperm, so condoms are ineffective at blocking HIV. Meanwhile, experts have promoted condoms as effective tools in blocking the spread of AIDS, which inspires a false confidence in the public, which causes people to become sexually-active. When their condoms fail to block HIV transmission, these people become infected.

The church's argument contains many flaws, but I shall confine my analysis to matters of fact. The World Health Organization (WHO), which has studied the epidemiology of HIV/AIDS perhaps more than any other entity, has repeatedly reaffirmed the scientific basis for condoms' usefulness in combating the spread of the disease. WHO has initiated condom distribution programs in many developing countries where HIV infection has already reached epidemic levels precisely because of their clinical effectiveness. Responding to the Catholic Church's allegations, WHO called them "dangerous when we are facing a global pandemic which has already killed more than 20 million people, and currently affects at least 42 million." While condoms do occasionally break and can permit the passage of semen, they reduce "the risk of infection by 90 percent and [are] certainly secure enough to prevent passage of the virus if not torn." (Source) True, this is not 100% effectiveness, but it is far better than zero.

Skeptics would not ordinarily comment on Catholic liturgy or the modern interpretation of it that declares the use of artificial contraception (especially condoms) to be immoral. No skeptic could properly object if the Catholic church had continued to justify its opposition to condoms on religious grounds. However, the church has removed its objections from the realm of religion and asserted a clinical claim. This claim is falsifiable — and is factually wrong and perhaps even socially dangerous, as WHO says. Therefore, skeptics will wade into this debate to aid the process of sorting fact from fiction. (Please excuse my pun.)


One common misunderstanding plagues skeptics, and we face an unfortunate volume of unwarranted derision for the ideas we do not profess. Skepticism's detractors usually agree with skepticism's basic approach to determining factual truth — once they have made an good faith effort to understand what skeptics advocate. Unfortunately, most detractors never make the effort: they assume that investigation constitutes an attack and simply counterattack. For most skeptics, investigations are honest attempts to understand a claim, not an assertion that the claim is inaccurate. To wit, such an assertion would violate the skeptical credo if it is made before the evidence is properly collected and evaluated.

This misunderstanding arises most frequently when skeptics investigate empirical claims made in a religious context. Some of these claims necessarily implicate the existence of a deity (or at least whether a particular phenomenon is a manifestation of a deity's actions). Misinformed zealots see skepticism as antithetical to religion because we seek evidence for what they purport to believe solely on the basis of scripture. Religion is founded upon faith, they argue, and it therefore cannot (1) require evidence as a prerequisite to belief or (2) provide such evidence. No skeptic will ever attack a religious belief for its adherents' failure to produce proof of its accuracy. In fact, most of us see religion as a harmless diversion that produces beneficial outcomes in the world — especially in the form of political action practical charitable activity.

The end result of this discussion is that skeptics do not seek evidence of religious beliefs so long as they are stated as religious beliefs based solely on faith. However, religious adherents occasionally make claims that an aspect of their religion is scientifically and empirically verifiable (or worse, that it has already been scientifically and empirically verified). Such claims leave realm of religious beliefs: they are, by definition, testable claims — which skeptics will test, just like any other falsifiable claims. Claims of "proof" of religious phenomena demand our attention, because their implications are extraordinary. Imagine: proof of the existence of a god! Skeptics take these claims seriously and try to investigate them dispassionately. Unfortunately, the religious adherents who make the claims frequently balk at the level of "proof" that skeptics regard as essential. They label us heathens and antichrists and blame us for everything from AIDS to September 11.

Skeptics take particular interest in claims that a phenomenon cannot be explained in any manner other than recognition of some supernatural or paranormal cause. In the way such claims are usually stated, the identification of any natural cause will disprove the claim. Some skeptics have acquired great skill in designing experiments to test such hypotheses. (See, e.g., James Randi and CSICOP.) When claimants first see the necessary experimental controls, they often accuse skeptics rigging the experiment against them and harboring a prejudicial animosity toward them. In reality, the skeptical demand for proof of the validity of such artifacts as the Shroud of Turin and such phenomena as crying statues, stigmata, psychic media, crop circles, and extra-terrestrial visitations is no higher a bar than skeptics demand of all phenomena, including — especially — those claimed by scientists! Despite the fact that the overwhelming majority of alleged supernatural and paranormal phenomena have been exposed as frauds, hoaxes, or the result of some ordinary physical process, no skeptic would ever claim that all such phenomena fall into these categories. Many are as yet unexplained, and skeptics do not discount the possibility that some or all of them could be the result of paranormal forces or beings. However, it is axiomatic that extraordinary claims require extraordinary evidence.

For a professional skeptic's view on skepticism, see this article by Michael Shermer. A Google search for Mr. Shermer's name reveals his prominence in the skeptical movement.

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